WoodWorks Shearwalls Canada - Change History

 

This document provides descriptions of all new features, bug fixes, and other changes made to the Canadian version of the WoodWorks Shearwalls program since its inception.

 

The most recent major release of Shearwalls is Shearwalls 2020, released on December 22, 2020. The most recent service update is Update 3, released on June 21, 2022.

This file last updated with changes on Aug 30, 2022.

           

Click on the links below to go to the changes for the corresponding release.  

Shearwalls 2020, Update 3

     Shearwalls 10 - WW 10

Shearwalls 2020, Update 2

     Shearwalls 9.3.1 / 9.3.2 – WW9, SR-3a

     Shearwalls 2020, Update 1

     Shearwalls 9.3 – WW9, SR-3

     Shearwalls 2020

     Shearwalls 9.2 – WW9, SR-2

     Shearwalls 10.3 – WW 10, SR-3

     Shearwalls 9.1 – WW9, SR-1b

     Shearwalls 10.2 - WW 10, SR-2

     Shearwalls 9.0.1 – WW9, SR-1a

     Shearwalls 10.1.1 - WW 10, SR-1a

     Shearwalls 9.0 – WW 9

     Shearwalls 10.1 - WW 10, SR-1

     Older Versions

 

 

 

Shearwalls 2020, Update 3 (Version 11.3) – June 21, 2022

 

A:  Engineering Design and Loads Analysis

1. Association between Sheathing Capacity and Nail Spacing for O86-09 Design (Bug 3662)

When O86-09 design code was selected, the program included the 5” nail spacing input choice that had been added for the Version 11, even though O86-09 table 9.5.1A did not include this option. This caused the association between input nail spacing and the sheathing capacities to be broken such that for 5”, 4” and 3” nail spacing, the program used the capacity for the next lowest nail spacing listed in the O08-09. For 2” spacing the program assigns zero capacity and zero loads to a shearline with such walls.

For the O86-14 and O86-19 design codes, there were no such problems because a mechanics-based rather than tabular approach is used for shear wall capacities.

2. Negative Dead Loads (Bug 3718)

Dead loads entered with a negative sign are now considered to be oriented upwards. Previously they were treated the same as positive dead loads.

This change allows you to adjust the distribution of dead forces to the ends of shear wall segments to account for different assumptions than those we use in distributing these forces, such as to account for mechanical uplift from cantilevered floors.

Negative dead loads are shown with the direction of the arrow reversed to point upwards. When combined with wind loads the load combination factor used is the 0.9 counteracting factor at the compression end rather than the tension end, and the 1.25 factor at the tension end.

3. Deflection and Hold-down Analysis for Overlapping Offset Shear Walls (Bug 3665)

The analyses of hold-down forces and of shear wall deflection were not properly handling the case where offset shear walls overlap longitudinally within the same shearline.

The hold-down forces on the overlapping segments were sometimes being assigned to the wrong overlapping wall segment, and these forces were used for the hold-down component of the deflection calculation.

In the Hold-down design output table, the program was outputting the wrong hold-down wall name, location and/or position incorrectly for these hold-downs.

In practical structures, this can occur if you create a large shear wall offset, for example 4 feet, which is generally not recommended. It has been corrected, nonetheless.

4. Minimum Shearline Requirements for Torsional Analysis Message (Change 69)

The message indicating that there are not sufficient shear lines to ensure torsions for rigid diaphragm design has changed from saying that two are required in each direction to two in one direction and one in the orthogonal direction.

B:  Input and Program Operation

1. Keyboard Shortcuts in Load Generation Details (Bug 3401)

In Load Generation Details and Torsional Analysis Details output viewer, the assignment of the  Ctrl+V shortcut key has been changed to allow you to paste content into the document. Previously this shortcut was used to tile the view vertically, which can still be done using a command under the Window menu.  

2. File Save of Ceiling as Diaphragm Checkbox (Bug 3583)

After a project was saved with the Ceiling acts as upper-level diaphragm checkbox in Structure Input view checked, it did not remain checked when the file was reopened. This has been corrected.  

3. Input Nomenclature for Foundation Elevation (Change 126)

In the Levels data group of the Structure Input Foundation elevation has been changed to Base elevation to reflect the fact that some light-frame wood buildings are on top of non-wood above-ground level such a concrete podium rather than a foundation.  

4. Crash upon Change of Multiply Selected Sheathing after Design (Bug 3690)

After design, if the exterior sheathing type for multiply selected walls was changed to a non-wood structural panel (gypsum-based, lumber sheathing, or fiberboard), the program immediately shut down without issuing a warning.

This did not happen for interior sheathing but did happen when Both sides the same is selected. The first selection does not have to be wood structural panel (WSP), it happened when you start with one non-WSP and change to another non-WSP. It has been corrected.  

C:  Output and Graphics

1. Display of Manually Entered Building Masses (Bug 3458)

The display of building masses in Load Generation view now includes manually entered masses. Previously they were not included because they are not automatically generated, but since they are intermediate to generating seismic loads, they should be shown.

Since by default building masses are not shown in Loads and Forces view, it was unclear to many users where these masses were.

2. Output of Hold-down Information Instead of Vertical Elements (Bug 3665)

Occasionally, hold-down forces that came down over a segment that is too narrow to be considered a full-height segment, or over a gap between shear walls, were not associated with a vertical element on the level below as they ordinarily are. No vertical element appeared in Elevation view or in the Location column of the Hold-down Design output table. In the line in this table for the lower level, sometimes a hold-down model from a neighboring wall is shown, along with capacity and design ratio, when it should say Refer to upper level. At other times these lines are blank.

This has been corrected and vertical elements now appear at all such locations.  

3. Hold-down Force Symbols and Shear Force Descriptions in Elevation View (Bug 3690)

The following changes have been made to the Elevation view legend and symbols:

a) Overturning Hold-Down Forces

The symbol S that appears below the hold-down symbol and before the magnitude of the overturning forcehas been changed to T for tension (upwards) forces and C for compression (downwards) forces. Separate lines explaining T and C in the legend replace the single line for S.

The “S” meant “overturning due to shear force”, which was not apparent to many users.

b) Horizontal Shear Force Descriptions

The descriptions under Factored Forces, Horizontal that used to say

 

Vs – Shearline force

Vs / diaphragm length

V / full height sheathing

 

now say

 

Shear line or wall segment force V (lbs)

Diaphragm-to-collector force V/L (plf)    

Shear wall design force v = V/FHS (plf)

 

The descriptions were changed to indicate the significance of each force.

4. Column Headings in Hold-down Displacement Table (Change 116)

The following changes have been made to the headings of the columns in the Hold-down displacement table of the Design Results,

a) Horizontal Hold-down Deflection Column

The final column entitled Hold defl has be changed to Horz defl, because it confused some users into thinking the value corresponds to the vertical hold-down displacement from the hold-down database, whereas it refers to the horizontal deflection given in the fourth term of the deflection equation in O86 Table 11.7.1.2.

b) Vertical Hold-down Displacement Column

The final column entitled Elong/disp has changed to Vert Displacement. Elong is an obsolete term referring to the separate calculation of the hold-down device elongation without including fastener slippage. This method is not included in the current version of the program.

5. Table Notes to Gravity-induced Lateral Demand Irregularity (Feature 266)

The notes and descriptions under the Irregularities table explaining why the program does not consider Irregularity 9, Gravity-induced Lateral Demand, have been revised to better explain why, that is, that predominant yielding mechanism, the sheathing nails, are unaffected by gravity-induced lateral demand as from a cantilevered floor contributing to overturning. Hold-downs are affected, but they do not provide significant ductility so are not the predominant yielding mechanism.

a) Numbered Note

The numbered note referring to this irregularity has been changed from

Not applicable, as Shearwalls does not include gravity-loaded elements that can induce lateral forces.

to

Not applicable to structures using wood shear walls.

b) Description

In the list of descriptions of all the irregularities,

Pertains to elements such as sloped columns that impart gravity loads to the lateral system. Shearwalls does not include such elements, so this irregularity does not apply.

 has been changed to

Any such demands in a typical wood-frame structure, such as from cantilevered floors, affect the overturning force on hold-downs; however these are not the predominant yielding mechanism so this irregularity does not apply.

6. Out of Plane Shear Strength Symbol in Components and Cladding Output (Change 109)

When either O86-14 or 086-19 design codes are selected, in the legend to the Components and Cladding table, the symbol vpb for planar shear in out-of-plane bending has been changed to vpsb, in accordance with the change in nomenclature in O86-14 Tables 9.3A-C.   

7. Default Values in Site Information Output (Bug 3601)

Following a sequence of steps involving running design, closing, reopening, and re-running design, all the information shown in the Site Information table of the Design Results were the default values that come with the program when first installed, rather than the ones that were set before the design was originally run. However, the design results are correctly based on loads generated using the using your inputs and not the default values.

For example, if 0.52 kPa velocity pressure and gust factor of 2.4 were input in the Site Information dialog box, the output table showed 0.45 kPa and 2.0, the default values, instead of the values you input, but 0.52 kPa and 2.4 were used to generate loads. 

This has been corrected and the data used for design are now shown in the output.

 

 

Previous Versions

An asterisk (*) indicates that the change was added to this record after the release of the version in which the change occurred

 

Shearwalls 2020, Update 2 (Version 11.2) – April 19, 2021

1. License Server Connection Error on Startup (Bug 3642)

If the current user was not the one to install WoodWorks and had not already run WoodWorks 2020 prior to update 1, an error message stating "Unable to run WoodWorks because you are not connected to the Internet or unable to contact license server" was incorrectly being displayed on start-up preventing WoodWorks from running.   This happened to a small but significant number of users.

 

Shearwalls 2020, Update 1 (Version 11.1) – March 3, 2021

1. Crash on Design for Structures with Non-Shearwalls (Bug 3609)

Starting with version 11.0, for any structure having a non-shearwall, the program crashed upon running design. This has been corrected.

2. Crash on Accept Design for Shearwalls Combined with Non-Shearwalls (Bug 3635)

For structures that have interior non-shearwalls and shear walls on the same shearline, the program crashed when the Accept Design button was pressed, even prior to version 11.0. This has now been corrected.

Examples of this configuration are a line with exterior shear walls and interior non-shear walls, and any interior line with shear walls and non-shearwalls.

3. Crash on Generating Low-Rise Wind Loads on Variable Height Blocks (Bug 3625)

When low-rise wind loads were generated on buildings in which attached blocks have a difference of two or more in the number of levels, the program crashed. This has been corrected.

4. Plywood and OSB Wall Sheathing Materials (Change 124)

a) Sheathing Thicknesses

Published metric plywood and OSB wall sheathing thicknesses when converted to Imperial and shown in Wall Input view are now rounded in most cases to the nearest 32nd to conform with current publications and marketing. They had been shown to the closest 16th.

i. OSB

12 mm OSB is now shown as 15/32” rather than ½”. This eliminates the duplicate size ½” corresponding to 12 mm and 12.5 mm sheathing. 15 mm is now 19/32” rather than 9/16 and 18 mm is 23/32” rather than 11/16”. 18.5 mm OSB remains ¾” rather then 23/32” to distinguish it from the 18.0 mm size.

ii. Plywood

18.5 mm plywood has been changed to 23/32” from ¾”. 7.5mm plywood is still shown as 5/16”, although it is closer to 9/32”.

b) Design Thickness

When Imperial units were used, the program designed for shear resistance from both panel bending and nail strength from O86 11.6.2.2 with the nominal Imperial thickness rather than the actual metric thickness. When combined with the coarse rounding, this led to errors as much as 6% in the thickness used in these calculations. The program now uses the published metric value for design calculations even when working with Imperial units.

c) OSB Material Name

In the input list of sheathing Materials, the name OSB const has been changed to OSB.

5. Repeated Input of Non-uniform Closed Openings Category (Bug 3634)

In the Openings drop list input of the Load Generation Site Information, the second of three choices, Non-uniform, resistant, closed was repeated in place of the third choice, which should be Large, often open.  When the third choice was selected, the program generated loads for an open structure, the problem was only in the wording, which has been corrected. 

 

 

Shearwalls 2020 (Version 11.0) – December 22, 2020

The links below lead to descriptions of the features added to WoodWorks Shearwalls 2020, and other changes made to the program:

A: Update to CSA O86-19 – General 1

1. CSA O86-19. 1

2. Choice of Design Codes and Standards. 1

3. Update of Clause References. 1

4. Removal of Load Combinations from NBC. 1

5. On-line Help. 1

B: CSA O86-19 Provisions. 1

1. OSB W24 Panels (Table 9.3) 1

2. Embedment Strength for Sheathing Connection Resistance (11.6.2.2) 1

3. Modification Factors Rd and Ro and Building Categorization (11.8.1) 1

4. Nail Diameter Maxima (11.6.1.1 and 11.5.5.2) 1

5. Minimum Side Member Thickness (12.9.2.2) 1

C: Other Engineering Design. 1

1. Non-ductile Critical Design Modes (O86 11.8.1) 1

2. Intermediate Data for Bx used for Torsional Irregularity (Feature 217) 1

3. Hold-down Forces Used to Determine Displacements for Torsional Irregularities (Bug 3351) 1

4. 20% Drag Strut Increase for Low Seismic Zones (Bug 3591) 1

5. 125 mm Nail Edge Spacing (Change 99) 1

6. Minimum Nail Penetration Depth (O86 12.9.2.2) 1

7. Slow Torsional Seismic Design for Structures with Numerous Hold-downs (Bug 3602)* 1

8. Shear Results Legend. 1

9. Units in Detailed Shear Wall Design Output (Change 119) 1

D: Load Generation and Force Distribution. 1

1. Transfer of Torsional Moment Due to Variable Accidental Eccentricity (Bug 3543) 1

2. Drag Strut Display and Output (Feature 177) 1

3. Crash on Generate Loads for Multiply Indented Structures (Bug 3495) 1

4. Multi-block Low-rise Hip End Warning Message (Change 107) 1

5. Design Spectral Response Accelerations in Seismic Load Generation Details (Change 104) 1

6. Default Self-weight Units (Change 97) 1

E: Program Operation. 1

1. CAD Drawing Import Procedure (Change 89) 1

2. Options Settings and Show Menu for Elevation View (Change 57) 1

3. Menu Item for Auto-saved Files (Change 39a) 1

4. Default Size for New Openings (Change 51) 1

5. Repeating Screen Message upon Change of Gypsum Fastener Length (Bug 3529) 1

6. Crash upon Missing Wall Stud Database File (Bug 3550) 1

7. View Style in Design Results Window (Change 25) 1

 

A:  Update to CSA O86-19 – General

1. CSA O86-19

The program now implements the CSA O86-19 Engineering design in wood design standard, including Update 1, March 2020.

Although O86-19 is referenced by NBC 2020, the program continues to implement the NDS 2015 design code for the time being. 

2. Choice of Design Codes and Standards

In the Design Code drop list in the of the Design settings, the choice CSA O86-19 / NBC 2015 has been added to the existing choices.  

This selection is reflected in the Design Settings output, the About Shearwalls box accessed from the Help menu, the Welcome box and the Building Codes box accessed from Welcome box.

3. Update of Clause References

All references to O86 clauses in the program input, output, and messages were changed to refer to the clause numbers in O86-19 if CSA O86-19 is selected. Virtually all references to shear wall design provisions under 11.1-11.6 changed; those in 11.7 relating to deflection and 11.8 relating to seismic design did not. References to the structural panel tables were changed from 9.3A, 9.3B and 9.3C to 9.1, 9.2 and 9.3. and nail design clauses under 12.9.3 were changed to 12.9.4.   

4. Removal of Load Combinations from NBC

The definition of load combinations used in Shearwalls that was in O86 5.2.4.1 has been removed entirely from the design standard, which now refers to the identical load combinations listed in the NBC.  

The only reference to these load combinations, in the Hold-down Design table legend to O86 Table 5.2.4.1, has been changed to NBC Table 4.1.3.2.A.  

5. On-line Help

The On-line Help has not yet been updated where necessary to reflect changes in the O86-19 other than design code clause reference numbers.

B:  CSA O86-19 Provisions

1. OSB W24 Panels (Table 9.3)

The program now includes W24 OSB sheathing panels from O86-19 Table 9.3 (previously O86-14 Table 9.3C), which has values of for shear-through-thickness rigidity Bv for thicknesses 9.5 mm and 11 mm.

a) Input
In the Wall Input view, W24 has now been added to the Panel Mark list. When a list of thicknesses the list of thicknesses 9.5, 11.0, 12.0, and 12.5 should appear. The final two are alternative thicknesses from Table A.9 and use design values for 11.0 mm panels. 

b) Component and Cladding (C&C) Design

Because bending strength mp and planar shear strength in bending vpsb are not published in O86-19, the out-of-plane sheathing capacity for C&C design cannot be calculated.

i. Sheathing Materials by Wall Group Table

A note number “7” appears for W24 wall groups in the Notes column of the Sheathing Materials table, referring to a note saying design for C&C wind loads is not possible.

ii. C & C Results Table
In the C&C Results table, two asterisks instead of a design capacity appears for sheathing bending capacity for walls with W24 sheathing, referring to a note for materials with no sheathing capacity.   

2. Embedment Strength for Sheathing Connection Resistance (11.6.2.2)

In O86-19 11.6.2.2 a) for sheathing-to-framing connection resistance, in the calculation of Nu from 12.9.3.2, the side member embedment strength f1 is now permitted to permitted to be calculated as

f1 = 51 (1 - 0.1dF).

In 12.9.3.2 the formula is

f1 = 104 G (1 - 0.1dF),

where specific gravity G = 0.49 for DFP and 0.42 for CSP and OSB.

Effectively this says that it is permissible to use DFP strength for all plywood and OSB sheathing panels.  

a) Setting

A new Design Setting has been added, 

Use DF specific gravity G for nail embedment strength f1 in O86 12.9.3 (as per 11.6.2.2).

When selected, the program applies the DFP G = 0.49 to the calculation of f1 for Nu

b) Detailed Shear Wall Design Output

In the Detailed Shear Wall Design output,

i. Symbols Section 
The following symbol definitions have been added

f1 - Wood embedment strength                                   

G - Specific gravity of framing material                                        

ii. Equations Section
The equation

f1 = 104 G (1 - 0.1dF),

has been added to the Equations section.

iii. Parameter List

In the list of parameter values shown beneath the symbols, the value of G has been added, followed by (DF plywood) if DFP had been used in place of CSP or OSB.

iv. Calculations
The choice of calculation method shows up in the nu value in the Detailed Shear Wall Design results.

3. Modification Factors Rd and Ro and Building Categorization (11.8.1)

In 11.8.1, Seismic Design Considerations, General, 

a) Nail Failure Mode c)
Nail mode c) has been added to the list of modes from O86 clause
12.9.4.2 which must be critical for shear wall failure ensure ductility. As mode c) is a double-shear mode, this has no effect on the current Shearwalls program. Internally, the change has been made to accommodate a possible future implementation of mid-panel shear walls.

b) Critical Panel Buckling

The proviso for the use of the ductility-related and overstrength modification factors Rd and Ro values from Table 11.5 that failure is governed by sheathing-to-framing connection has been removed from the O86-19. We were informed that the removal was in error; however Shearwalls did not implement this proviso. Refer to C: 1 below for the implementation of this proviso for this version. 

c) Seismic Zone vs. IEFaSa(0.2)

The criterion from the NBC used to determine whether clauses 11.8.2 -11.8.6 are to be implemented has changed. In O86-14, these clauses they are applied if the value of IEFaSa(0.2) is equal to or greater than 0.35. In O86-19, they are applied if the Seismic Category is SC3 or SC4 rather than SC1 or SC2, these categories being determined from IES(0.2) and IES(1.0) in NBC 2020 4.1.8.5.

As the program has yet to implement NBC 2020, it still uses IEFaSa(0.2) >= 0.35 as the criterion.

i. Clauses Affected

For the higher IEFaSa values (O86-14) or SC’s (O86-19), all of 11.8.2-11.8.6 is applied as stated. These pertain to 20% hold-down force increase (11.8.2), overcapacity coefficient/ratio (11.8.3), diaphragm design force (11.8.4), diaphragms with non-wood Shearwalls (11.8.5), and 20% transfer element force increase (11.8.6).

For the lower values or categories, 11.8.7 is used, which specifies that only 11.8.6 fully applies, and that 11.8.4 and 11.8.5 apply but with overcapacity coefficient Ci = 1.0.

4. Nail Diameter Maxima (11.6.1.1 and 11.5.5.2)

The maximum nail diameter for shear wall sheathing from O86-19 11.6.1.1 has been increased from to 3.76 mm from 3.66 mm in O86-14 11.3.1.1, and the limit for walls without hold-downs (Jhd <1) from 3.25 from O86-14 11.4.5.5 to 3.33 in O86-19 11.5.5.2.

This change acknowledges the current widespread use of nails of the ASTM F1667 nail design standard rather than the obsolete B111. WoodWorks earlier received authorization to use the ASTM diameters as limits, so no there was no change to design or program operation, other than to remove a note to that effect that appears under the Sheathing Materials table when these nails are used. 

5. Minimum Side Member Thickness (12.9.2.2)

The minimum plywood or OSB side member thickness for a nailed connection from O86 12.9.2.2 has changed from 3.0 nail diameters to 2.5.

This minimum was not applied to the sheathing-to-framing nail connection in Shearwalls. Refer to C: 7 below for the new implementation.

C:  Other Engineering Design

1. Non-ductile Critical Design Modes (O86 11.8.1)

WoodWorks has clarified with the design standard authorities the meaning of the following provisos in O86 11.8.1. In both O86-19 and O86-14,  

 

The sheathing-to-framing connections shall be designed to yield in mode c), d), e), or g) shown in Clause 12.9.3.2 for nails to ensure ductility in the shearwall and diaphragm.

 

In O86-14,

 

The corresponding ductility-related seismic force modification factor, Rd, and system overstrength related force modification factor, Ro, for shearwalls are given in Table 11.8.1, provided failure is governed by sheathing-to-framing connection.

 

We have been informed that this latter statement was removed from the O86-19 in error, and we regard it as still in force.

We have also been informed that both these statements mean that when Rd and/or Ro are other than 1.0, shear walls that have brittle non-ductile critical design modes are considered to fail. These critical modes are either the nail resistance mode from O86 12.9.3.2 or when panel bending strength from 11.6.2.2.(b) governs over sheathing connection strength from 11.6.2.2.(a).

We have implemented these provisos as follows:

a)  Design Search
In the design search in which parameters defining the wall have been left unknown, the program now passes over those walls for which a non-ductile mode governs. 

b) Detailed Design Output
If a wall has a non-ductile governing mode when all parameters were selected or when the end of the design search was reached, a note appears at the bottom of the section in the Detailed Design results for that wall, saying the wall fails, giving the reason. Priority is given to panel buckling failures if both criteria are non-ductile.

c) Design Results

In the Shear Results table, for walls with governing non-ductile modes governs, a symbol appears next to the design ratio, and a warning is placed below the table saying that the wall failed either because of a critical non-ductile nail mode or because panel buckling governed. The note is followed by a list of failing walls.

d) Design Summary

If any walls have a governing non-ductile mode, a line is output in the Design Summary giving the list of such walls.  

2. Intermediate Data for Bx used for Torsional Irregularity (Feature 217)

At the end of the Torsional Analysis Details file, there is now a table showing the intermediate data used to determine Bx = δmax / δavg , from NBC 4.1.8.11 where δ is the structural displacement on extreme perimeter shear walls on each level induced by forces acting at +- 0.1Dnx from the center of mass on that level. Dnx is the building width on that level. Bx is used to determine torsional irregularity as per 4.1.8.6.

These data are shown for each level of the structure, each of the 4 force directions, and for the cases of positive accidental eccentricity and negative accidental eccentricity added to the torsional moment.

The table shows the shear line forces used to determine perimeter story drift (with Bx = 1.0 and 10% accidental eccentricity), the story drift on the extreme left and right shear lines, the average of the story drifts, and the ratio of maximum drift to average.

The table has notes explaining the meaning of the data and their consequences in the NBC provisions.

3. Hold-down Forces Used to Determine Displacements for Torsional Irregularities (Bug 3351)

In detecting Torsional Irregularities using NBC 4.1.8.11.(10) the program was using hold-down forces derived from the worst case of positive or negative accidental eccentricities to calculate the displacements used for both the positive and negative eccentricities. The effect of this was to increase the lesser of the deflections and reduce the difference in displacements that creates torsional irregularity.

This has been corrected and hold down forces are calculated for the positive and negative eccentricities independently for the purpose of calculating displacements and

4. 20% Drag Strut Increase for Low Seismic Zones (Bug 3591)

The 20% increase in seismic drag strut forces mandated by O86 11.8.6 was applied only for high seismic zones, defined in O86 11.8.1 when IaSaFa(0.2) from the NBC is greater than 0.35, however, it should have also been applied for low seismic zones as per 11.8.7.3;  i.e. the factor should have always been applied.

Furthermore, the Drag Strut Forces table legend referred to O86 11.8.2, which gave the increase for hold-downs, anchorages, etc. but should have shown 11.8.6, which is for drag struts and other lateral force transfer elements.

The Elevation view legend now shows the line Drag strut = 1.2 under Factors for low seismic zones. It correctly referred to the 11.8.6 clause number. 

The user’s file was a single block, single level structure, for which IaSaFa(0.2) = 0.33 is shown in the Irregularities table and the drag strut force could be derived directly from the shear line force, indicating that no increase had been applied. No reference to the increase appeared in Elevation view, but the reference to 11.8.2 appeared in the Drag strut table. 

When the importance factor was changed such that IaSaFa(0.2) = 0.382, then the drag strut force is 20% greater than that derived from the shear line force alone.  References appeared in both Elevation view and the Drag Strut table.

This has been corrected.

5. 125 mm Nail Edge Spacing (Change 99)

5” or 125 mm was added to the edge nail spacing choices in Wall Input view. This spacing is sometimes used in publications and occasionally in practice.

6. Minimum Nail Penetration Depth (O86 12.9.2.2)

The program now implements the minimum nail penetration depth in O86 12.9.2.2 of 5 times fastener diameter d for plywood and OSB.

The program calculates penetration by subtracting the sheathing thickness plus the gypsum underlay thickness from the nail length. If the result is less than 5 nail diameters, the shear wall design is considered to fail.

If the program is searching through unknown parameters for a design, such a wall is passed over.

If the wall has been completely specified, a failure is reported and an existing message about zero capacity walls is shown at the bottom of the Shear Results table.

It is not possible to create this condition without the use of gypsum underlay. Even with gypsum underlay it cannot occur for standard nails, and a combination of a thick, short power-driven nail is needed, for example a 2” x 3.33 mm nail with 18.5 mm sheathing plus 5/8” gypsum underlay. In that case there is 16.25” penetration but 16.65” is required.

7. Minimum Sheathing Thickness for Nail Sizes (O86 12.9.2.2)

The program now implements the minimum side member thickness for nail strength in O86 12.9.2.2 of 2.5 times fastener diameter d for plywood and OSB.

After changing the panel thickness in Wall Input View, only those nails that satisfy the 2.5d minimum thickness are included in the nail selection list, so that large diameter nails are excluded when using thin plywood. This only applies to 5/16” (7.5mm) plywood, because 3/8” (9.5 mm) plywood is more than 2.5 times as thick as the largest allowable nail diameter from O86 11.6.1.1 (3.76 mm).

8. Slow Torsional Seismic Design for Structures with Numerous Hold-downs (Bug 3602)*

For buildings with numerous hold-down locations, an internal error slowed rigid diaphragm seismic design calculations to the point that the program hanged for a long time after the design button was pushed, and eventually showed Not responding in the title bar. The slow-down was directly proportional to the number of hold-downs, so it was significant for a structure with multiple floors, numerous shearlines, and many wall segments.  

An example of a structure experiencing this problem had four levels with 11 shearlines on the first, second and third levels and nine on the fourth, with as many as six segments on a shearline on each level.   

9. Shear Results Legend

The following changes have been made to the Shear Results table legend

-        It is explained that Vhd is Vrs without Jhd, as Vhd is no longer defined in the O86.

-        For the sheathing connection resistance equation:

-        Equation and reference for vd based on fastener strength Nu has been added.

-        The number of shear planes, ns, was removed, as it is always 1.0.

-        Definitions and references have been added for shear wall factor JD, unblocked factor Jus and fastener spacing factor Js

-        For the panel buckling resistance equation:

-        Definitions and references have been added for the load-duration factor KD, service-condition factor KS, and treatment factor KT

-        It is indicated that KD = 1.15 and KT = 1.0

10. Units in Detailed Shear Wall Design Output (Change 119)

In the Detailed Shear Wall Design report, the words Units shown in has been added above the column headers Equation and Table. This is to clarify that one unit shown is for how it appears in the tabulated results, and the other unit is the assumption used in the list of equations.

D:  Load Generation and Force Distribution

1. Transfer of Torsional Moment Due to Variable Accidental Eccentricity (Bug 3543)

The method that was used to transfer the torsional moment for rigid diaphragm analysis downwards between levels by applying the upper-level force at the center of mass of that force to the level below, assumes that the accidental eccentricities (ae) are the same on each level, however ae's can be different due to a different building width on adjacent levels. This could lead to an inaccuracy in the torsional analysis used to distribute the seismic forces to shear lines on the lower level.

This has been corrected by applying an effective accidental eccentricity on the level below equal to (aeu*Fu + ael*Fl) / (Fu + Fl), where aeu and ael are the design code mandated ae's on the upper and lower level, and Fu and Fl are the total forces from loads applied on each level. Refer to the Online Help topics on the vertical distribution of rigid diaphragm shear force for a derivation of this adjustment.

In the Torsional Analysis Details output, when this occurs, a line is added to give the effective accidental eccentricity and the adjustment equation. The line showing the total force F used for torsional analysis on the level now shows the value of Fl, the force from loads only on that level. This appears regardless of whether differing ae's exist, as it is useful information at any time.

This issue affects seismic analysis as this is the only design case with accidental eccentricity.

To gauge the impact of the change:

Case 1 - A penthouse on the upper level, assuming that the mass per unit foot is the same as on the lower level. The maximum difference occurs when the penthouse is 41% of the lower-level width, where the effective ae is 60% of the regular ae.

Case 2 - A 6-story tower where five upper stories are narrow, supported by a podium base that is 3 times the width of the tower. The effective ae is roughly half the regular ae.

Case 3- A building shaped like an inverted pyramid. Such a building would be very non-conservative in that the additional width in two dimensions would not be accounted for on the level below. Such buildings are rare but exist.

2. Drag Strut Display and Output (Feature 177)

The following changes have been made to the display of drag strut forces in Elevation View.

a) Location of Symbol and Force

The symbol with a circle and arrow showing the drag strut force has been moved up to be just below the top of the wall. Previously the forces were shown at the top of openings. The drag strut forces are typically in the top plate of the wall, not the opening headers, and this change avoids conflict with the new force-transfer strap forces.

b) Direction of Arrow

The direction of the force arrow now indicates whether the drag strut is in tension or compression at that point. Previously the arrows always pointed away from the opening or wall end.

An arrow in the direction of the shearline force is in tension, one contrary to the shearline force is in compression. An arrow in the same direction as the shearline force pointing into an opening segment is dragging the force over the opening into the full height segment. An arrow in the opposite direction pointing into an opening segment shows the full height segment resisting force being pushed into it from over the opening.

The following change has been made to the output of drag strut forces in the Collector Forces table of the Design Results (formerly Drag Strut Forces)

c) Negative Compression forces.

The magnitude of the drag strut a force in compression is shown with a negative sign. The legend explains that positive numbers are in tension, negative ones in compression.

3. Crash on Generate Loads for Multiply Indented Structures (Bug 3495)

For a specific single block multi-level long structure with numerous small indentations, the program crashed upon generating seismic loads. This has been corrected.

4. Multi-block Low-rise Hip End Warning Message (Change 107)

In the screen message that appears when low-rise wind loads are generated with multiple blocks, the program would warn of both hip ends being treated as side panels and of unequal hip end slopes even if only one of these was true. This has been corrected. 

5. Design Spectral Response Accelerations in Seismic Load Generation Details (Change 104)

Based on the Design Setting selection for NBC 2010 and NBC 2015, the values of design spectral response accelerations that were used in the calculation of lateral seismic design force at the base from NBC 4.1.8.11 are now output in the Seismic Load Generation Details. If NBC 2010 is selected S(0.2), S(0.5), and S(5.0) are output and if NBC 2015 is selected S(0.2) and S(2.0) are output.

6. Default Self-weight Units (Change 97)

In the Default Settings, the units for self-weight have been changed from kN/m2 to kPa. These units are equivalent, but kPa is used more often in publications. 

E:  Program Operation

1. CAD Drawing Import Procedure (Change 89)

The CAD Import Wizard has been improved to make it easier and more intuitive to add drawings for multiple levels. Previously, it was unclear to some users that you had to press Start positioning to scale the CAD drawing, and the sequence between scaling and adding new levels could be confusing. The Wizard now guides you through a sequence of steps for each level.

2. Options Settings and Show Menu for Elevation View (Change 57)

The following changes have been made to the Display items in the Options Settings, and/or the corresponding items in the Show menu, which control program elements to display or output.

a) Center of Loads and Center of Rigidity

Checkboxes for Center of loads and Center of rigidity have been added under Elevation view in the Options Settings. Previously, they had only been in the Show menu. 

b) Aspect Ratio

Aspect ratio has been moved to appear below Segment numbers.

c) Nailing Information and Legend

The Nailing information used to mistakenly hide and show the legend. It has now been renamed Legend. Nailing information now is shown and hidden via the Sheathing information item.

d) Shear Force and Capacity
An item has been added to show or hide the design shear force and combined capacity information, which previously were always shown. This allows the entire material specification \to be removed if all Show menu items are turned off.

3.  Menu Item for Auto-saved Files (Change 39a)

A new menu item Open Autosaved File menu has been added under File menu to provide direct access to auto-saved backup files BackupPre.wsw and BackupPost.wsw. Refer to the On-line Help for the use of these files. Explanatory status bar messages are displayed if you hover over the menu items.

4. Default Size for New Openings (Change 51)

Now, the default size for new openings is 3 feet with an offset of 2.5 feet from bottom of the wall, approximating the size for a window. Previously the default size for a new opening was 6.75 ft approximating the size for a door.

5. Repeating Screen Message upon Change of Gypsum Fastener Length (Bug 3529)

In the Wall Input form, when fasteners less than 1-3/4” was selected for the GWB Type X material, and then you make any other action, a message pertaining to nail sizes intended for wood structural panels appeared. It kept re-appearing, making it impossible to proceed to the design stage unless you selected a larger fastener.  This has been corrected.

6. Crash upon Missing Wall Stud Database File (Bug 3550)

If a wall stud database file used in a Shearwalls project was no longer in your installation or no longer referenced by the database.ini file, the program would show a blank Framing Material in wall input view, and eventually crash upon design if an available material was not selected in its place. The program now outputs a warning and selects an available material if it detects this condition.

7. View Style in Design Results Window (Change 25)

After running design, thee Design Results are now shown in the last selected view style, Wide View or Preview.  Previously it returned to Preview each time. The program still defaults to Preview on the first design run.

8. View Change of Spelling in User Interface (Change 111)*

All references in the user interface to “shearwalls” and “shearlines” have changed to “shear walls” and “shear lines”, as this is the correct spelling and the one used by CSA O86.

 


Shearwalls 10.3 – Design Office 10, Service Release 3 – June 11, 2020

1. Vertical Distribution of Rigid Diaphragm Forces (Bug 2733)

a) Compounding of Accidental Eccentricity

Starting with version 10.2, the vertical distribution of rigid-diaphragm shear force amplified the effect of accidental eccentricities on lower levels, such that the total force applied to the shearlines was increasingly larger than the applied shear force F as you moved down the structure. The total shear line force should equal the applied shear force F on that level and all levels above, plus the effect of taking the worst-case of positive and negative accidental eccentricities on each level. This effect is usually small, creating shearline forces typically 10% greater than the applied shear force F, but the amplification of eccentricities created shear forces much larger than F, and an overly conservative design.

This amplification occurred because the shearline forces created using the effect of accidental eccentricity were applied to the level below and used to determine torsions on that level, so that effectively the center of mass from the upper level was shifted by the accidental eccentricity n-1 times at the base of an n-level structure, when it should only be shifted once.

This has been corrected.

b) Vertical Transfer of Rigid Diaphragm Wind Forces for Cantilevered Diaphragms (Bug 3526)

For wind loads, the program applied the shear line forces from flexible diaphragm analysis on the level above to rigid diaphragm torsional analysis on the level below. This was intended as a convenient way to apply the total loading on the level above at its center of loading to the level, but can be inaccurate in the case of cantilevered diaphragms such as occur at roof overhangs and where perimeter walls are non-shear walls.

The program now applies the total vertically accumulated load from the levels above at the centroid of these loads to the level below, for wind loads as well as seismic loads.

2. User-Defined Shearline Forces for Rigid Diaphragms (Bug 3528)

User-defined forces entered in load input view were being added to shearline forces already derived from rigid diaphragm torsional analysis of applied loads, however such forces used to model the effect of forces from adjoining structures should be included in torsional analysis. As a message that appears when load input view is invoked, giving this as a reason to add these forces, they are now treated as if they were loads on the level on which they are entered and applied to the torsional analysis.

An exception is made when there are no applied or generated loads on the level, only user-applied shear line forces. In this case we can assume that you do not want to perform rigid load distribution and wish to analyze individual shear lines with forces calculated manually.

Furthermore, for wind loads, the force was transferred to the level below only if it was defined for flexible diaphragm analysis as well as rigid. For seismic loads, it was not transferred below at all. This inconsistency has been corrected by this change, and if both loads and shearline forces are applied on a level, the effect of the forces is transferred to the level below as if they were loads. If only user-applied shear line forces are added, there is no vertical transfer. Note that flexible diaphragm user-applied forces are still transferred below in all circumstances.

3. Fundamental Period Ta for Single-Storey Buildings

When calculating the fundamental period Ta using the formula in NBC 4.1.8.11 (4) (a) for single-storey structures, Ta = 0.05 hn3/4 + .004L, the value of L, the shortest distance between shear resisting elements, was mistakenly divided by about 16.4, rendering this contribution negligible, so that the period was effectively the same as that used for multi-storey structures from 4.1.8.11 (3) (c). hn is the building height.

As the same spectral acceleration value S(Ta) is used in the generate loads for all values of Ta less than 0.2, from 4.1.8.4.(9),  this will not have an effect except for very long structures. The value of Ta for single-story structures is too low to impact other design code provisions based on Ta.

For example, for a one-storey, flat-roofed 24’ x 40’ building, the program calculated periods of 0.0994 s in the east west direction and 0.0987 s in the north-south direction, but these should be 0.127 and 0.146, respectively. These values appear as the default Ta in the Site information dialog and, rounded to 0.099, in the Seismic Load Generation details.

This problem has been corrected.

4. Storey Weight with Manually Added Building Area Masses (Bug 3537)

When manual area building masses were added to lines or walls in both the E-W and N-S directions, the story weight Wx used to generate seismic loads as per NBC 4.1.8.11 (7) was inaccurate in an unpredictable way depending on load length and the tributary width, and could be several times higher or lower than the weight of the input masses. The incorrect weights appeared in the base shear distribution table of the Seismic Load Generation Details and the Seismic Information table of the Design Results. This has been corrected.

This did not occur when manual masses were entered in just one direction.

In a typical example of a single block of 40 x 40 feet with a gable roof with 25 psf roof self- weight and 3 manually applied 30 psf area building masses with a tributary width of 5 feet on lines A, B and 1, Wx was 130,350 lbs when it should have been 62,100 lbs.

Masses are used to generate loads in both directions, so it was possible to model all building masses by adding them to shear lines in just one direction to avoid this problem, which has been corrected.

5. Flexible Distribution of Manually Applied Low-rise Shearline Forces in Windward Direction (Bug 3549)

The program was adding manually entered shear line forces in one direction only to forces created by the flexible distribution of low-rise wind loads from southeast and northwest windward corners, even though “Both” was selected as the direction when inputting these forces. The incorrect forces appeared in Plan view and the Shear Results and Deflection tables of the Design Results.

In an example project, a N->S shear line force was shown as 4153 lbs when it should be 4653 lbs. In the S->N direction, it was correctly shown as 4653 lbs.

6. Crash upon Adding Uplift or Dead Loads with Vertical Shearline Offsets (Bug 3518)

The program crashed upon adding dead or wind uplift load to shearlines that had vertical offsets between levels. However, these loads could be added to shearlines that lined up and had no vertical offsets. This has been corrected.

 

Shearwalls 10.2 – Design Office 10, Service Release 2 – July 30, 2019

1. Use of CSA O86-14 with NBC 2010 (Design Office Feature 24)

The program now allows you to select the CSA O86-14 wood design standard with the 2010 NBC building code. Although the O86-14 is referenced by NBC 2015, it is permissible to use it with the NBC 2010, which references CSA O86-14, and some jurisdictions have not yet adopted NBC 2015.

If there is a conflict between CSA O86-14 and NBC 2010 provisions, the NBC 2010 provision is used to ensure compliance.

a) Input

In the Design Settings, the choice CSA O86-14 / NBC 2010 has been added to the Building code dropdown box.

b) Design

For those jurisdictions still complying with NDS 2010, this option allows for shear wall design based on nail strength and panel buckling introduced with O86-14, rather than the more conservative tabular approach used in previous editions. This and other differences with using O86-14 as opposed to O86-09 are described in Shearwalls 9.3 - CSA O86-14 Design Standard, below.

c) Program Information

The design codes and standard chosen are reflected in the Welcome box, the Help/ About Sizer box, and the Building Codes box, and in the Design Settings output.

2. Vertical Distribution of Rigid Diaphragm Shearline Forces (Bug 2733)

We have changed the way the program incorporates forces from shearlines on upper levels in the rigid diaphragm analysis on the level below.

a) Previous Procedure

In versions before Shearwalls 10.2:

i. Wind

For wind design Shearwalls included the unfactored shearline forces derived from flexible diaphragm analysis on the level immediately above and added them to the applied loads on the level for which rigid analysis was being performed. The shearline force was then factored by 1.4 for wind design.    

ii. Seismic 

For seismic design Shearwalls included the applied loads from all levels above and added them to the applied loads on the level for which rigid analysis was being performed.

b) New Procedure

For both wind and seismic design, the shearline forces arising from rigid diaphragm analysis from the level immediately above are applied to the rigid diaphragm analysis on the floor below. For each shearline, the worst case of forces from positive and negative accidental eccentricity on the level above are those which are transferred.  

c) Background and History

i. Rationale for Previous Procedure

When the rigid diaphragm procedure was implemented along with multi-story analysis in version 2002 of the program, there was concern that the torsional effect of the accidental eccentricities applied on the level above should not be carried through to the level below for two reasons:

1. Probability of Simultaneous Occurrence

It was thought that accidental eccentricity is entirely to account for inaccuracies in the distribution of mass in a structure, and that it was unlikely that these inaccuracies or variabilities would occur on each level and in the same direction.

2. Compounding of Accidental Eccentricity

There was concern that the eccentricity would unnecessarily compound, that is, the effect of eccentricity on the level above creates amplified forces that would be further amplified by the eccentricity on the level below.

ii. Implementation of Previous Procedure

1. Use of Flexible Diaphragm Forces

We received guidance at that time that it would be acceptable to apply loads derived from flexible forces on the floor above to rigid analysis on the level below. This was applied to both wind and seismic design, even though there is no requirement for accidental eccentricity for wind design.

An accidental eccentricity of 10% of building width is required for seismic design as per NBC 4.1.8.11.(11). 

2. Use of Applied Loads for Flexible Diaphragm Seismic Design

The seismic requirement for flexible diaphragms of 5% accidental eccentricity, from NBC Structural Commentary 174, was added to the program for version 8, in 2011. To avoid compounding this eccentricity, applied loads on the levels above were used in lieu of shearline forces. This was an internal change only, there is no effect on the resulting torsional moments.

d) Reason for Change

i. Probability of Simultaneous Occurrence

The USA ASCE 7 C12.8.4.2 says that it is “typically conservative to assume that the center of mass offsets of all floors and roof occur simultaneously and in the same direction.” That is, as we cannot know for certain which levels and directions the accidental eccentricities occur in, it is best practice to assume they occur on all levels.

ii. Effect of Compounding vs Flexible Diaphragm Inaccuracy

Typically, accidental eccentricity adds approximately 10% force to the shearline experiencing the greatest effect. Compounding this effect on the floor below by adding 10% of 10% = 1% is not a significant increase and is much less than the inaccuracy that arises from using the flexible diaphragm forces from the shearlines above. Flexible diaphragm analysis can result in a markedly different distribution of force than the rigid diaphragm force, and by using flexible forces, the program was not transferring the inherent torsion from the floor above to the one below.

iii. Natural Component of Accidental Eccentricity

According to NBC Structural Commentary 175, about ½ of the 10% accidental eccentricity is due to natural torsional effects such as dynamic amplification, so that component should always be transferred to the level below.

iv. Wind Loads

As there is no accidental eccentricity requirement for wind, the rationale for the previous procedure does not apply to wind design, which should use the forces that arise from rigid diaphragm analysis.

e) Consequences of New Procedure

i. Distribution of Non-torsional Direct Forces

The new procedure uses the direct forces due to shear wall stiffness on the level above, rather than those arising from flexible analysis. As we are assuming rigid diaphragms on all levels, this is a significant improvement in the accuracy of the procedure.

ii. Distribution of Inherent Torsional Forces

The new procedure transmits inherent torsional forces due to physical offset between the center of mass and center of rigidity, and these forces contribute to torsion on the level below. This is the correct procedure, as an object when subject to torque twists throughout its whole length. The old procedure did not transmit torsion between levels. 

iii. Distribution of Accidental Torsional Forces

On each line, the program transmits the maximum force from positive and negative accidental eccentricity. As such, the new procedure will transmit the increase in force due to accidental torsion but will not transmit the torsional effect of that force, as the worst case of the positive and negative accidental torsions on opposite extremities of the structure tend to cancel.

We believe this is an acceptable compromise between the conservative procedure described in ASCE 7 C12.8.4.2, and the non-conservative procedure of not including accidental eccentricities from the floor above on the floor below at all.

3. Vertical Transfer of User-applied Seismic Shearline Forces (Bug 3467)

When a seismic shearline force was added directly to a shearline using the Add as a factored force directly… input in the Add Load input form, for rigid diaphragm analysis the force affected only the level it was added on and was not being transferred below for inclusion in the torsional analysis on the level below.

This has been corrected in the course of implementing the changes in Bug 2733, above, Vertical Distribution of Rigid Diaphragm Shearline Forces.

4. Multiple Wall Selection in Load Input View (Feature 252)*

It is now possible to select multiple walls on which to apply loads in the Add Load dialog. Once walls are selected using the Control Key or Select All command, upon entering the Add Load dialog,

-        Point loads cannot be selected,

-        Apply to is disabled and shows Selected Walls,

-        The From and To locations are blank and disabled,

-        The Add as a factored force directly to the shearline is not available.

Loads are then added on all selected walls, with the Magnitude From and To being the load magnitude at the start and end of each wall. 

5. Wind Load Generation on Multiple Blocks

The following problems pertaining to the generation of wind loads on adjoining blocks have been corrected.

a) Low-Rise End Zone in Interior of a Building Face (Bug 3472)

When the wind load method for low buildings from NBC Figure 4.1.7.6.-A. is used for multiple blocks, end zones were created at the end of each block, for both walls and roofs. This would create unnecessary end zones in the interior of the structure where one block joins another.

For walls, these end zones were created on interior corners, and where the end of one block is collinear with the side of another block. For roofs, they are created when a hip roof joins a block with a side panel of the same angle, so end zone is created in the middle of a continuous compound roof panel.

End zones are no longer created in these areas, which are considered part of the building faces 1-4.

b) Low-rise End Zone for Shadowed Blocks (Bug 3464)

When a block was adjoined to another block such that there were no walls on one of the faces of the block, the end zone on both walls and roof panels on the opposite face of the block would extend the entire width of the block, rather than the end zone width specified in NBC Figure 4.1.7.6.-A. This would create larger wind loads than expected on the face.

c) Shadowed Blocks with Roof Overhangs (Bug 3465)

When a block with roof overhangs was adjoined to another block, the program would create loads on the roof the block was adjoined to in the portion shadowed by the block, even if the Exclude roof portion covered by other block checkbox in the Load Generation input was checked. This happened when using the load generation procedures for low buildings and for all other buildings.

6. Low-rise Wind Load Generation for Flat Roofed Buildings (Bug 3474)

In the case of buildings with flat roofs, the generation and distribution of low-rise loads using NBC Fig 4.1.7.6 were incorrect in several ways. In such buildings, the longest direction of the building is considered to be the direction parallel to the ridge line for buildings with roofs. The following problems were identified:

-        Case A (transverse to long direction) loads were being generated on end walls; however such walls are not loaded in the NBC model.

-        Some Case A loads were being created with the magnitude intended for Case B loads, and vice versa.

-        For torsional analysis of load Case B (wind force parallel to long direction), no force was being included parallel to the long direction.

These problems occurred on all levels of the structure and have been corrected.

7. Design Spectral Acceleration Values in Seismic Load Generation Details Output (Change 104)

The design spectral acceleration values S(T) at period T = 0.2, 0.5, and 5.0 from NBC 4.1.8.4.(9) are now output in the Seismic Load Generation Details file under the Total Design Base Shear table. These values are used to calculation the maximum base shear Vmax from 4.1.8.11.(2)(c), and the overturning reduction coefficient J and higher mode factor Mv from 4.1.8.11.(6). Their inclusion should some of the other calculations shown more transparent, such as the equivalence of Vmax and Vcalc for certain site classes and locations, because S(0.5) = S(0.2) = S(Ta) for Ta <= 0.5 for cases. Refer to NBC Commentary J-140 which shows this situation for Site Classes D and E in Vancouver.  

8.  “Getting Started” Steps (Change 103)

The instructional steps that appear when the program is run or “Getting started” is invoked from the toolbar have been revised, clarified and updated. Some of the more significant changes are:

a) Default Values

A “Step 0” has been added suggesting setting defaults for building elements, and the subsequent steps indicate how those defaults are used to create the structure.

b) Edit Walls

Explanations of the ability to change the location and size of walls via the wall input form, the selection of Standard Walls, designing for unknowns, and designing as a group have been added.

c) Edit Hold-downs

A Step 7 has been created for editing hold-down device information, by moving instructions from other steps.

d) Generate Loads

An instruction to set the Wind Load Generation Procedure has been added, and the procedure of creating seismic loads in stages with self-weights on each level explained more clearly.

e) Add or Edit Loads

The need to add dead loads to counteract overturning, and wind uplift loads, has been emphasized. An explanation of changing building masses and returning to regenerate loads has been added, as has the case of not generating loads and adding loads to check a single shearline. The unusual case of modifying generated loads has been removed.

f) Design

Several design settings have been added to the recommendation to set the Rigidity and Deflection options before designing. The mention of design processing time has been removed, as it is no longer a major issue.

g) Accept or Adjust Design

A Step 15 has been added for the Accept Design feature.

h) Detailed Results Output

The step formerly called “Log File Output” has changed to Detailed Design Results and lists the separate buttons and associated files for wind load generation, seismic load generation, and torsional analysis, that used to be in one file.

9. Force on Shearline with No Full Height Segments (Bug 3461)

Due to numerical rounding, some shearlines with numerous non-full-height sheathing segments and no full-height sheathing segments were assigned a shearline force when they shouldn’t have been. These shearlines were included in the Shear Results output table and a failure reported for them.

This problem happened infrequently and has been corrected.   

10. Drawing of Vertical Element for Offset Openings in Elevation View (Bug 3463)

When the end of an opening on an upper storey is over the interior of an opening on the floor below, the drawing in Elevation view of the vertical element extending from the bottom of the upper floor joist to the top of the opening was no longer visible because it was obscured by the gray shading over non-full-height sheathing segments that was introduced with version 10.

This has been corrected.

11. Default Imperial Snap Increment (Change 94)

The default snap increment when Shearwalls is shipped is 100 mm, so when you changed your default unit system without adjusting the snap increment and opened a new project, the snap increment would be 3.94”, which is awkward to work with. The program now uses a default of 3” in this circumstance.

If you reset to the original setting while in Imperial units, it is reset to 3” rather than 3.94”. 

12. Wind Uplift Loads on Selected Walls (Change 95)

For wind uplift loads, in the Application input of the Add a New Load dialog box, you can now add the loads to selected walls. Previously only the full wall line was available.

13. Display Control for Hold-down Design and Drag Strut Force Tables (Bug 3228)

The inclusion of the Hold-down Design and Drag Strut Forces tables in the Design Results output is now controlled by separate items in the Show menu and in the Options settings. Previously they were both controlled by a single item in the Loads and Forces settings.  

14. Colour of Selected Shearlines (Change 96)

When a wall is selected in Plan view and turns orange, the other walls on the shearline turn a darker colour of orange (or brown). Previously they were purple.

15. Order of Framing Materials in Wall Input (Change 100)

The dropdown list of in the Materials input in the Framing section of Wall Input View was mistakenly ordered alphabetically, so that proprietary SCL materials rarely used as wall studs were given first. This has been corrected and common lumber materials appear first.

 

Shearwalls 10.1.1 – Design Office 10, Service Release 1a – May 7, 2019

1. Deflection Convergence for Close to Zero Force on Segment (Change 45g)

The convergence routine for equalizing deflections along the shear wall as required by SDPWS 4.3.3.4.1 sometimes left a small residual force on a segment that should not attract any force, causing the program to report that it could not equalize deflections. The program now zeroes out the force if it is less than 0.05 plf, that is, what appears as 0.00 in the output. Note that it adds this small force back into the pot to be redistributed to other shearlines, so it isn’t leaking forces if several segments are zeroed out.

2. Missing Framing Material Crash Upon File Open (Bug 3439)

When a project file was opened opens that contained a framing material that was not amongst the materials listed in the Framing Materials drop down, starting with Version 10.1 the program crashed instead of showing you a message about the missing database file.

The message has been restored and the program now longer crashes in this situation.

Note that problem can be rectified by activating the material database file with Database Editor.

3. Standard Wall Nail Diameter Persistence (Bug 3427)

Values of power-driven nail diameters entered into Standard Walls were not being saved, so that when standard walls created with a nail diameter, are used when the program is reopened, the nail diameter used was the default diameter based on the common nail of the closest length to the power-driven nail.

This has been corrected and standard wall nail diameters now persist when a file is reopened.

 

Shearwalls 10.1 – Design Office 10, Service Release 1 – March 27, 2019

The links below lead to descriptions of the changes made for version 10.1 of WoodWorks Shearwalls.

 

A: Building Model and Shear Wall Design. 1

1. Power-Driven Nail Design Using CSA O86-09 (Bug 3406) 1

2. Design Assumptions for Weight Irregularity 2. 1

3. Constant Detection of Torsional Irregularity 7 for Seismic-only Design (Bug 3350) 1

4. Data Related to Hold-downs in Standard Wall Groups (Bug 3409) 1

5. Update of Roof Joining (Bug 3377) 1

6. Outsize Openings after Change of Wall Height (Bug 3347) 1

7. Gypsum Underlay in Sheathing Materials Table Legend (Change 43) 1

8. Deflection Settings Output when Deflection Analysis not Performed (Change 83) 1

B: Load Generation and Distribution. 1

1. Separate Wind and Seismic Details File (Change 1) 1

2. Generate Loads Dialog Update (Change 8) 1

3. Update of F(T) in Site Information. 1

4. Nonsensical Seismic Forces (Bug 3362) 1

5. Torsional Analysis Report for Flexible Diaphragm Wind Design (Change 55) 1

6. Seismic Load Generation Details Formatting. 1

7. Wind and Seismic Procedure in Site Information Table (Change 17) 1

C: Input and Program Operation. 1

1. Re-appearance of Plan View Input Forms (Change 37) 1

2. Crash on Corrupted or Empty Hold-Down Database (Bug 3375) 1

3. Log File Menu Item (Change 2) 1

4. Link to Video Tutorials in Help Menu (Change 29) 1

5. Wall and Shearline Input Form.. 1

6. Disabled Worst-Case Rigid vs Flexible Diaphragm Setting (Change 54) 1

7. Dropdown Box Style for Wall and Opening Hold-down Input (Change 82) 1

8. Tool Bar Menu Item Spelling. 1

9. Warning and Informational Messages. 1

 

A:  Building Model and Shear Wall Design

1. Power-Driven Nail Design Using CSA O86-09 (Bug 3406)

The following problems when using the CSA O86-09 design code is set, pertaining to the design of shear walls using power driven nails according to Note 5 of Table 9.5.1A, which refers to the procedure in A9.5.1, were corrected. 

a) Shear Capacity Adjustment Factor

The program was using the capacity corresponding to the standard nail in Table 9.5.1A smaller than the power-driven nail, then increasing the capacity listed in table by the square of the ratio of the power nail to the standard nail. However, A.9.5.1 says to use the standard nail size larger than the power nail size and decrease the capacity by the square of the ratio.

This created small errors in capacity for nails greater than 2.84 mm in diameter, the smallest standard nail diameter in table 9.5.1, and for known sheathing thickness, power-driven nails less than 2.84 mm diameter had zero capacity when they should have had a factored capacity.

b) 80% Diameter Rule

The program was allowing nail sizes less than 80% of the smallest size listed in Table 9.5.1 (2.84 mm) and calculating nail size adjustment factors from A9.5.1 based on that, even though A9.5.1.1 limits the allowable nails to those within 80% of the sizes listed in 9.5.1.  These factors were only applied for unknown sheathing thickness due to item a), above.     

Note that the smallest standard nail size in Shearwalls is 2.87 mm, corresponding to the ASTM F1667 wire gauge size corresponding to 2.84 in the obsolete CSA O86 B111 nail standard. The program however limits nails to at least 80% of 2.84, or 2.272 mm.

2. Design Assumptions for Weight Irregularity 2

The following changes were made to the detection of Structural Irregularity 2 - Weight (mass) in NBC Table 4.1.8.6.

a) Definition of a Storey (Bug 3423)

The program was using the definition of a “storey”, italicized in Table 4.1.8.6 to indicate that is from the definitions in Division A, 1.4.1.2, as the distance from the top of one floor to the top of the floor above it. The roof was considered a separate storey because of the line in 4.1.8.6 saying “A roof that is lighter than the floor below need not be considered. “, implying a heavier roof need be considered as a separate storey.

However, we have received advice that the same definition of building levels used for vertical seismic force distribution should be used, that is, from the middle of the wall on one level to the middle of the walls on the level above. In this model, a roof is considered part of the upper level.

The reason for this re-evaluation is that the purpose of the weight irregularity is to make sure the structure behaves as assumed in the Equivalent Static Procedure, which is based on the first (near-linear) mode of the “lumped mass” dynamic response model that is used for vertical seismic load distribution. The linear mode assumption requires a relatively uniform mass distribution amongst the storeys. 

Furthermore, an identical irregularity provision in the USA ASCE 7 Table 12.3-2, Irregularity 2, uses the term “effective mass”, rather than the weight of a storey.

The interpretation of a storey as per the literal NBC definition caused problems with the following situations, that are eliminated by using the vertical seismic force distribution definition:

-        at the definition of a storey from a floor to a ceiling was not being applied for the case of roofs on top of cathedral ceilings

-        if buildings have trusses and you enter the mass of the whole truss system, including the ceiling, as the roof load, when the ceiling should have been part of the upper storey.  

-        when partition wall masses were incorporated into the mass of the floor load, they would be placed on a storey below where they should be

b) Inclusion of 25% of Snow Load (Bug 3422)

The storey weight for the roof did not include 25% of the snow load that is used in seismic load generation, but it should have been included, as the irregularity description in Table 4.1.8.6 includes the symbol Wi, which is defined in NBC 4.1.8.2 as a portion of W, and in the definition of W, it includes 25% of the snow load.

Therefore, the snow load is now included in the weight of the uppermost level as defined in item (a) above.  

3. Constant Detection of Torsional Irregularity 7 for Seismic-only Design (Bug 3350)

The program reported a torsional irregularity for all or most structures when only seismic loads were applied to the structure, regardless of whether this torsional irregularity existed. As a result, the Design Summary indicated that due to an irregularity, seismic design was not valid, and the Irregularities table in the Design Summary showed the irregularity 7 failing in one direction, and a red note at the top saying the Equivalent Static method is not available for that reason. This has been corrected.

4. Data Related to Hold-downs in Standard Wall Groups (Bug 3409)

Wall parameters related to hold-downs were being included in the definition of standard walls, although they are not part of the material specification intended to be part of a Standard wall: As a result, the following would occur if these were changed for a wall:

-        If Design in Group was not selected, the wall would no longer be designated as being one the Standard walls. Extra design groups would be created for all the walls affected.

-        If Design in Group was selected, the change would be propagated to all other walls that were part of the Standard wall group.

a) Hold-down Data

The following data were not available for selection in Standard Wall mode, but were being treated as Standard Wall parameters:

-       hold-down model,

-       number of brackets,

-       whether to apply the same hold-down to the openings.

b) No. of End Studs

The number of end studs, which is used only for hold-down design, has been removed from the standard wall definition for the purpose of design grouping but is retained in the Standard Wall mode of Wall Input View for the purpose of creating default walls.

Hold-down related information is no longer included in the Standard Wall definition because hold-downs are designed separately from walls, and it is desirable to group walls according to wall materials only.

5. Update of Roof Joining (Bug 3377)

For multiple blocks, the program occasionally failed to update the roofs according to the input in the data group Construction in Roof Input View in the following ways:

a) Disabled Joined Selection

If there is another block that a roof could join to, the Joined selection was sometimes disabled so the operation was impossible.  

b) Gable and Hip Selections

When roofs are joined in the N-S direction, the Gable and Hip selections sometimes had no effect and the roof remained joined when selected.

These have been corrected.

6. Outsize Openings after Change of Wall Height (Bug 3347)

When the wall height is changed in Structure input, the program now adjusts the top of any openings to ensure that they remain within the confines of the wall and removes the openings that would have no height if this is done. 

7. Gypsum Underlay in Sheathing Materials Table Legend (Change 43)

The legend entry GU - Gypsum underlay thickness is now displayed in Sheathing Materials table in the Design Results when CSA O86-14/NBC 2015 is selected. Previously it displayed only when CSA O86-09/NBC 2010 was selected.

8. Deflection Settings Output when Deflection Analysis not Performed (Change 83)

In the line saying Linearized deflection equation in the Design Settings output, if Include deflection analysis is unchecked in Design Setting, No deflection analysis is shown rather than Never or Always. The deflection equation is irrelevant if there is no deflection analysis, and the Include deflection analysis setting was not previously reported in the output.

B:  Load Generation and Distribution

1. Separate Wind and Seismic Details File (Change 1)

The program now outputs two separate files for wind and seismic load generation, rather than both in one file as before. The file extensions are .sws and .sww instead of .log. The files are accessed by two icons in the toolbar.

2. Generate Loads Dialog Update (Change 8)

In Generate Loads dialog, the following values reverted to their original values after being edited and you clicked anywhere outside the box before generating loads:

Seismic loads:

-       all self-weight text fields

-       horizontal projection check box

-       use wall self-weights…for Jhd calculations check box (Canada only)

Wind loads:

-       line/area load radio buttons

-       C&C wall loads check box

The program now retains all the inputs.

3. Update of F(T) in Site Information

The following problems regarding the update of site coefficients F(T) in the Site Information Dialog when the NBC 2015 design code setting is selected have been corrected. These values are editable when Site Class F is selected, as site specific analysis is required according to NBC 4.8.1.4.(6). Otherwise they are disabled and the values from Tables 4.1.8.4.-B-F appear.

a) Site Classes A to E (Change 16)

The program now updates the non-editable values of F(T) when Site Class A-E is selected when the peak ground elevation PGA value is changed, or the value of Sa(0.2) changes such that it switches between from being greater than or less than 0.8 PGA, as per NBC 4.1.8.4.(4). Previously the values only updated when the Site Information box was closed and reopened.

b) Upon Change of PGA for Site Class F (Change 10)

With Site Class F selected so the F(T) values are editable, after changing F(T) then the peak ground elevation value PGA, the F(T)’s reverted to their previous values.

c) Upon Return to Site Class F (Change 11)

When Site Class F is selected and F(T) values are edited, then changing to another Site class so that other non-editable values appear, and back again, the program now puts back the F(T) values that were previously entered rather than zeroes.

d) Verification upon Exit (Change 26)

If Site Class F is selected, and the F(T) values not changed from the default value of 0, the program now issues a warning message asking you to enter non-zero values. If OK is selected, you return to the input dialog; If Cancel is selected, the changes are reverted. Previously the program allowed you to save these values and generated seismic loads based on the zero F(T)’s, generating zero seismic load of all were zero.

The same functionality has been implemented for when the NBC 2010 design code setting is selected and Fa or Fv is zero when exiting the box. Previously these values defaulted to the those from the last site class selected; now zeroes appear when selecting Fa or Fv.

4. Nonsensical Seismic Forces (Bug 3362)

On rare occasions one or more shearline forces would be calculated with nonsensically high values. These values appeared in the Shear Results table and were reflected in the storey shear and diaphragm design forces in the Seismic Information table. This rarely occurring bug due to unusual values of torsional rigidity for flexible diaphragm design encountered in intermediate iterations and has been corrected.

5. Torsional Analysis Report for Flexible Diaphragm Wind Design (Change 55)

If a project is run such that torsional analysis is required, then the inputs are changed such that it is not and run again, the program retains the Torsional Analysis Details from the previous run. Torsional analysis is not required if the Rigid Analysis option is not selected in Structure Input view, and there are only wind loads on the structure, as seismic loads require flexible diaphragm torsional analysis.

6. Seismic Load Generation Details Formatting

The following minor formatting changes have been made to the Seismic Load Generation Details file. 

a) Decimal Places for Sa (5.0) (Change 15)

Four decimal places were output for the value of Sa (5.0), the 5% damped spectral response acceleration in the Seismic Load Generation Details. Now it is output with two decimal places.

b) Extra Line (Change 18)

An extra line appearing between the line reading Equations (units = N,m) and the Equations in the Seismic Load Generation Details file has been removed.  

c) Change in Subscripts for Distribution of Base Shear to Levels (Change 19)

The column headers hi, Wi and hi * Wi are now output as hx, Wx, hx * Wx in the Distribution of Base Shear to Levels table appearing in the Seismic Load Generation Details file. The change in subscript from i to x is because the subscript i is stated to be used for the level in summations in the Legend section, whereas x is for a particular level.

7. Wind and Seismic Procedure in Site Information Table (Change 17)

In the Site Information table of the Design Results, the words from and for appearing beside the NBC wind and seismic load generation procedure reference have been removed.

C:  Input and Program Operation

1. Re-appearance of Plan View Input Forms (Change 37)

When in Plan view and you close the input form, e.g. Opening Input, either by the exit button on the form window or by the Input Form icon in the toolbar, then go to another Plan view action, e.g. Roof Input, and return, the input form for the original action now re-appears. Previously it remained invisible and some users had difficulty making it reappear. 

2. Crash on Corrupted or Empty Hold-Down Database (Bug 3375)

If the hold-down database was empty or corrupted, a crash occurred on program start-up. The program now re-installs the original database if it encounters a corrupt or empty one.

It was possible to avoid the crash by deleting the corrupted hold-down database file.

3. Log File Menu Item (Change 2)

The File menu item Log File has been removed as what was previously the log file is now split into four text output files, none of which are referred to as “log files”.

The following files are now accessed from menu items in the View menu.

 

Wind Load Generation Details

Seismic Load Generation Details

Torsional Analysis Details

Detailed Shearwall Design

 

Note that they also have icons in the toolbar.    

In the View menu the word View has also been removed from Design Results View, for consistency with these menu items.

4. Link to Video Tutorials in Help Menu (Change 29)

An item Video Tutorials has been added to the Help menu for the link http://cwc.ca/woodworks-software/support-and-training/canadian-tutorials/  which goes to the WoodWorks video tutorials on the CWC website, where you will find numerous Shearwalls tutorials.

5. Wall and Shearline Input Form

The following changes were made to the operation of the Wall and Shearline Input form

a) Standard Wall Input Box Overlap (Change 5)

While in the Standard Wall mode, the dropdown box with the list of Standard Walls overlapped with the input box to the right showing the name of the Standard Wall being edited, and when dropped down it obscured part of the name of the Standard wall. There is no longer any overlap.

b) Shearline Selection in Wall Input View (Change 24)

The Shearline input is now disabled if there is no choice other than Auto. This input allows you to select the shearline a wall belongs to if the walls are within the allowable shearline offset of walls defining two or more shearlines. As the default offset in the Design Settings is only 0.15m, this rarely occurs, and the use of this input was unclear to some users.

6. Disabled Worst-Case Rigid vs Flexible Diaphragm Setting (Change 54)

In the Design Settings, the check box for Worst-Case rigid vs flexible diaphragms was disabled and showing as selected if only one of Rigid or Flexible Analysis was selected in the Structure input. Now it is shown as not selected (empty) in this case.  

7. Dropdown Box Style for Wall and Opening Hold-down Input (Change 82)

The hold-down model input in both wall and opening view has been changed from an editable drop-list to a noneditable list, as a hold-down typed into this input would not necessarily match with an existing one in the database.

8. Tool Bar Menu Item Spelling

The following spelling corrections were made in the items in toolbar dropdown menus

a) Drag Strut in Show Menu (Change 57f)

In the Show menu, under Forces, Dragstruts has been changed to Drag Struts.

b) Irregularities in Go To Table Menu (Change 87)

In the Go To Table menu under Design Results, Seismic Irregularities had the misspelling Irregulairites.

c) Storey in Go To Table Menu (Change 21)

In the Go To Table menu under Structural Data, Story Information is corrected to Storey Information.

9. Warning and Informational Messages

The following changes were made to the text in messages:

a) Warning Message for Rounded Opening Input Values (Change 48)

The warning message about opening input being rounded to the nearest snap increment, identified the input by long phrase that did not make sense in the context of the warning. It has now been abbreviated to briefly identify the input, e.g. Offset from edge. Square brackets around the input value have also been removed.

b) Loads and Forces Warning Message Misalignment (Change 4)

The warning message when Loads and Forces view for the first time had misaligned bullet points. This has been corrected.

c) Irrelevant Messages in Status Bar (Change 9)

Irrelevant messages from other part of the program operation were displayed in the status bar at the bottom of the program window upon hovering the toolbar items Go To Table, Zoom Out, Zoom in, Undo, Redo and getting Started.  These have been removed and nothing appears in the bar at this stage.

 

Shearwalls 10 –– Design Office 10 – January 31, 2018

The following major features are implemented for this version,

 

NBC 2015 – Wind Load Generation

NBC 2015 – Seismic Load Generation

5-and 6-Storey Design

Multiple Block Low-rise Loads

Improved Irregularity Detection and Design

Linearized Deflection Equation

Elevation View Improvements

 

The following is an index of links to descriptions of all the changes.

 

A: NBC 2015 and CSA O86-14 Updates - General 10

1. Choice of Design Codes and Standards. 11

2. CSA O86-14 Updates. 11

3. Synchronization of NBC and O86 Editions. 11

4. Design Code Clause References. 11

5. 5-and 6-Storey Design. 11

6. On-line Help. 12

B: NBC 2015 – Wind Load Generation. 12

1. Wind Load Generation Procedures and Methods. 12

2. Reference Height h. 13

3. Topographic Factor 14

4. Pressure Coefficients Cp for Buildings of Any Height 15

5. Pressure Coefficients CpCg for Low Buildings. 15

6. Internal Pressure Coefficient Cpi 16

C: Other Wind Load Generation. 17

1. Low-rise Wind Loads for Multiple Blocks and Eccentric Ridge Lines (Feature 26) 17

2. Low-rise Torsional Loads. 19

3. Case A Side, Case B End. 19

4. Show Menus (Bug 3240) 20

5. Partial Wind Loading Note. 20

6. Load Generation Details Output 20

7. Bug Fixes and Small Changes. 21

D: NBC 2015 – Seismic Load Generation. 22

1. Design for Low Seismic Loads. 22

2. Seismic Data. 23

3. Site Coefficients F(T) and Design Accelerations S(T) 23

4. Disallowed Irregularities for 5-6 Storey Wood Frame Construction. 24

5. Gravity-Induced Lateral Demand Irregularity Type 9. 25

6. Maximum Base Shear V. 25

7. Period Ta for Single-storey Wood Structures. 25

8. Higher Mode Effects Mv 26

9. Overturning Reduction Factors J and Jx 27

10. Base Shear Increase for User-input Ta for 5- and 6-Storey Buildings. 28

11. One-storey Buildings with Large Diaphragm Deflection. 28

E: Other Seismic Load Generation. 28

1. Period Restriction on Irregular Structures. 29

2. Vertical Stiffness Irregularity Type 1. 29

3. Weight (mass) Irregularity Type 2. 30

4. Re-evaluation of Discontinuity Irregularities Types 3, 4, and 5. 31

5. Deflection Analysis for Detection of In-Plane (stiffness) Irregularity Type 4. 32

6. Irregularity Table Changes. 33

7. Disallowed Irregularities for 5- and 6- Storey Structures. 34

8. Load Generation Details Output 34

9. Bug Fixes and Small Improvements. 35

F: Load and Force Distribution. 36

1. Sign Convention for Torsional Analysis. 36

2. Torsional Analysis Details Output 36

3. Bug Fixes and Small Improvements. 37

G: Deflection Analysis and Shearwall Design. 37

1. 3-term vs. 4-term Deflection Equation (Feature 211) 37

2. Design Results Output 39

3. Bug Fixes and Small Improvements. 41

H: Elevation View. 42

1. Zoom and View Settings (Feature 216) 42

2. Multi-storey Selected Walls (Feature 230) 42

3. Shading of Non-shear-resisting Segments (Feature 56) 43

4. Dimension Lines (Feature 79) 43

5. Display of Roof Line and Gable End (Feature 228) 44

6. Segment Numbers (Feature 77) 44

7. Bug Fixes and Small Improvements. 45

I: Plan View. 45

1. Mouse Zoom (Feature 219) 46

2. Wall Depiction in Plan View (Feature 56) 46

3. Design Case in Plan View (Feature 83) 46

4. Bug Fixes and Small Improvements. 46

J: Program Operation. 47

1. Separate Torsional Analysis and Load Generation Output 47

2. Settings. 47

3. Bug Fixes and Small Improvements. 48

 

A:  NBC 2015 and CSA O86-14 Updates 1 and 2 - General

The program now implements the 2015 National Building Code (NBC), but still retains the implementation of design with the NBC 2010 as a user option.

1. Choice of Design Codes and Standards

In the Design Code drop list the Design procedures data group of the Design settings, the choice CSA O86-14/ NBC 2010 has changed to CSA O86-14/ NBC 2015. The CSA O86-09/ NBC 2010 choice remains unchanged.

This change is also reflected in the output of the design settings, the About Sizer box accessed from the Help menu and in the Building Codes box accessed from Welcome box, and the Welcome box.

2. CSA O86-14 Updates

The program now indicates in the About Sizer box and the Building Codes box that the CSA O86-14 implementation now includes Update No. 1 from May 2016 and Update No. 2 from June 2017. The latter update caused some design code clause reference numbers to change.

3. Synchronization of NBC and O86 Editions

The program now does not allow you to generate loads with 2010 NBC and design with 2014 O86, or generate with NBC and design with CSA O86-09.

If you try to do so, when Design button is pressed, the program offers a choice of cancelling design or regenerating loads.

4. Design Code Clause References

The references to the NBC design code clause numbers in the input forms and screen messages, and in warnings, design notes and other program output, have been updated to show the 2015 edition clause numbers when CSA O86-14/ NBC 2015 is chosen as the design setting. It continues to show 2010 edition numbers when CSA O86-09/ NBC 2010 is chosen.

5. 5-and 6-Storey Design

In determining which NBC provisions should be included in the program and how existing ones were to be interpreted and implemented, consideration was given to the changes in NBC which allow 5- and 6-storey design for most wood structures, instead of the previous limitation to 4 storeys.

The changed provisions relate to permissible structures of combustible construction for fire safety – 3.2.2.50 for residential use (Group C) and 3.2.2.58 for business and personal service use 9 (Group D).

Note that neither the building area limitations nor the height limits for these provisions are checked by Shearwalls and it is your responsibility to ensure that your building is within these limits.  

6. On-line Help

The on-line Help in the old Windows format containing references to the CSA O86-09 design code provisions has been removed from the program. The newer Web Help showing CSA O86-14 references is retained. It currently refers to the NBC 2010 design code and has not yet been updated for Version 10 features and changes. This will be done over time and updates posted to the web site. 

7. Building Codes Box

The reference to NBC now indicates that it is Division B, Part 4 that is used. The full name of the Structural Commentaries is now given.

Under Mid-rise Wood Construction:

-       Design code provision reference numbers to NBC and CSA O86 are now given for all the line items about what is and isn’t included in Shearwalls. 

-       The line regarding increase in base shear due to manual T value has been moved from the section about what has not been implemented.

-       The line regarding special requirements for certain shapes has been removed.

-       A line about higher mode factor Mv and overturning reduction factor J has been added.

A section about Wind Load Generation has been added indicating that partial load cases from 4.1.7.9 and intermediate exposure factors Ce for change in terrain from 4.1.7.3.(5)(c) are not in the program.

 

B:  NBC 2015 – Wind Load Generation

The changes described in this section occur when NBC 2015 is selected as the design code edition in the Design Settings, unless otherwise indicated.

1. Wind Load Generation Procedures and Methods

a) Design Setting

The Design setting for Wind load generation procedure has changed to Wind load generation method to avoid confusion with the static vs dynamic procedures, which are now so named officially.

The choices referring to Commentary Figures 1-7/8 and I-15 have changed to

NBC 4.1.7.5 – Other buildings

NBC 4.1.7.6 – Low buildings

b) Load Generation Details

i. Header

In the header to the Load Generation Details file (previously part of the Log file), now states that the Static procedure from NBC 4.1.7.3 is used (4.1.7.3) then refers to the 4.1.7.5 or NBC 4.1.7.6 method selection.

For both 2010 and 2015 NBC selections, the program now gives the C&C procedure used, as one of

2010 all-heights: NBC Commentary Figure I-15 using Cp*

2010 low rise: NBC Commentary Figure I-8

2015 all-heights: Figure A-4.1.7.5.(4)

2015 low rise: Figure 4.1.7.6.-B

ii. Code References

Throughout the report, all design code references now refer to 2015 provisions when the 2015 NBC option is selected.

c) Site Dialog

In the header section of the Site dialog, the program now refers to the Static procedure from 4.1.7.3, and that the external pressure coefficients (Cp or CpCg) and the reference height h come from 4.1.7.5 or 4.1.7.6 according to the method selected.

d) Torsional Analysis Details

In the Torsional Analysis Details file (previously part of the Log file), NBC 4.1.7.5 and NBC 4.1.7.6 are now referred to instead of I-15 and I-7.

Where it previously said   Low-rise Case A, it now says Case A (NBC Figure 4.1.7.6.-A) 

e) Wind Shear Results Table

References to NBC 4.1.7.5 and NBC 4.1.7.6 have been added to the legend to the Shear results table.

f) Dynamic vs Static Procedure

NDS 4.1.7.1 and 4.1.7.2 clarify and solidify the conditions under which the Dynamic Procedure, which is not supported by Shearwalls, must be used. However, these Articles still do not state what height is to be used in the 4:1 height to width ratio used to classify a building as dynamically sensitive: the eave height, mean roof height, or ridge height.

i. Input

This design setting giving the choice of eave, mean roof, or ridge height has been renamed to indicate that it applies only to the classification of buildings in 4.1.7.2.  All other heights have been clarified by NBC 2015.

ii. Warning

The warning message when this ratio has been exceeded has been modified to include references to 4.1.7.2.(2)(c) and 4.1.7.1.(3).

2. Reference Height h

The definition reference height h, used for the calculation of exposure factors Ce and Cei has been moved from 2010 Commentary I 7 and I 8 to 4.1.7.3.(6) and 4.1.7.3.(7), respectively. Previously it was derived using an ill-defined building height H, but this height has now been precisely given in most cases as the mid-height of the roof.

The changes listed below apply to both the NDS 2010 and NDS 2015 design code selections.

a) Criterion for Choosing Method

A literal reading of 4.1.7.3.(6)(a) could lead to using exposure factors for buildings less than 20 meters and least plan dimension, even if Low buildings is not selected as the wind generation method. However, 2010 Commentary I-7 bases the choice of reference height on the definition in I-26 of low-rise buildings, and we do not believe it was the intention of NBC to change this.

Therefore, the use of 4.1.7.3.(6)(a) is dependent on the user selection of the 4.1.7.6 – Low buildings method, and 4.1.7.3.(6)(b) on 4.1.7.5 – Other buildings, not on the actual dimensions of the building.

b) MWFRS Method – Buildings of Any Height (4.1.7.5)

i. Leeward Surfaces

Previously, the program was using ½ the eave height for all leeward surfaces (walls, roofs, and gable ends); now it uses ½ the building height, which is ½ the ridge height.  

ii. Windward Roof Surfaces and Gable Ends

NBC 4.1.7.6.(3)(a) refers only to windward walls and no guidance is given for roofs. As the adjacent clauses refer to “surfaces”, and NBC 2010 I-7 referred to windward “faces”, we have assumed that the intention was that windward roof surfaces be treated the same way as walls.

Previously, the program was using the ridge height for windward roofs and gable ends. It now evaluates the pressures at increments of height, and computes a weighted average of the pressure which takes into account the diminishing width of hip panels, gable ends, and side panels on hip roofs. The height z reported is the centroid of the force distribution, i.e., the z at which the pressure is the same as the averaged pressure. 

c) MWFRS Loads – Low Buildings (4.1.7.6)

No changes were made to the calculation of reference value h for low-rise buildings’; it is still the greater of ½ the

d) C&C Loads

i. External Pressures

There has been no change to the reference height for external pressures for C&C loads, it is still taken as the height at the top of the building level.

ii. Internal Pressures

Previously, the program was using the same reference height for internal pressures Cei as for external pressures Ce. Now it uses the greater of 6 meters or ½ the ridge height, as per 4.1.7.3.(7),

e) Load Generation Details

In the Load Generation Details output, the reference height for internal pressures is now shown above the C&C loads table, where the mean roof height was previously shown. Mean roof height has been removed as it is not relevant to C&C loads.

The definition of the reference height in the Legend has been changed to reflect the new design code reference.

3. Topographic Factor

The equations for wind pressures in NBC 2015 4.1.7.3.(1) and (3) include a new topographic factor, Ct, defined in 4.1.7.4, which is algebraically identical the procedure in 2010 NBC which uses modified exposure factor Ce* and gust effect factor Cg* in place of Ce Cg, where Ce* is defined in Commentary I-14 and Cg* in Commentary I-21.

a) Ct Calculation

The program was modified to calculate Ct independently rather than modify Cg and Ce in order to display these values in the program output when NBC 2015 design is selected.  

b) Reference Height

The NBC 2015 has made it more evident that the height used for the Ct factor is always the height above the ground, z, whereas the Ce factor may have different heights depending on the building surface and the wind load method employed. In calculating Ce* for NBC 2010, the program had been using the same reference height as used in the Ce calculation.

The program now uses the height z above the ground for both the Ct factor for NBC 2015 and Ce* in 2010.  This is the weighted average height over the surface for MWFRS loads, and the height a building element at the top of a level for C&C loads. 

c) Low-rise Loads

The procedure for determining a modified gust effect factor for low-rise combined CpCg from 2010 Commentary I-21 has been removed for 2015, as it is no longer necessary.    

d) Averaging

NBC 4.1.7.3.(2) says that pressures are to be averaged over the building surface. Previously the program had been integrating C e* /Ce over the surface then multiplying with the average Ce. then calculating the gust effect factor Cg* using average Ce* and Ce.

Now the program integrates the value Ce (z) Ct(z) over the whole surface. The difference in these two approaches can be expected to be quite small.

e) Output

In the Load Generation Details file (previously part of the Log file)

-       A definition of Ct has been added to the legend, with 4.1.7.4. reference. 

-       A definition of z for topographic factor height has been added to the legend.

-       Definitions of Lh, Hh, and x have been added to the legend.

-       The equation for the topographic factor Ct is shown in the Equations section.

-       The values of Ct for each load are shown in a column in the load table.

-       The height z corresponding to the average Ct is shown in the load table for each load.

-       The asterisks in Ce* and Cg* when there is a topographic effect have been removed from the load table headers.

f) Other Changes

For both the NBC 2010 and NBC 2015 design selections, the symbols Hh, Lh, and x have been added to the Height, Length and From crest inputs. The units (ft. or m) now appear only once in the data group title.

For the NBC 2015 selection only, 2-D Ridge will be renamed 2-D Hill, to reflect the change in the design code nomenclature.

4. Pressure Coefficients Cp for Buildings of Any Height

In NBC 2010, pressure coefficients Cp for buildings of any height were found in Commentary I-29 and Figure I-15; in NBC 2015 they are in a new section, 4.1.7.5, and shown in Figure A-4.1.7.5.(2) and (3)  for MWFRS loads and Figure A-4.1.7.5.(4) for C&C. 

Previously, the building surfaces were referred to as “walls”, not they are called “faces”, implying the projected surfaces of roofs are treated as walls.

a) H / D Ratio

Previously, the program was using the ridge height for roof loads and the eave height for walls and gable ends when determining the height-to-depth (H/D) ratio. It now uses the same building height for walls, roof panels, and gable ends on the same face of the structure.  The height used is the ridge height for faces perpendicular to the ridge, and the mean roof height for faces parallel to the ridge. For flat roofs, it is the eave height.

This change is made for both NDS 2010 and NDS 2015 design setting selections.

5. Pressure Coefficients CpCg for Low Buildings

In 2010, pressure coefficients CpCg for low-rise buildings were found in Commentary I-27 and Figure I-7 for MWFRS loads and in Commentary I-28 and Figure I-8 for C&C loads; in NBC 2015 they are in a new section, 4.1.7.6, and shown in Figure 4.1.7.6.-A, for MWFRS loads and Figure 4.1.7.6.-B for C&C loads.

There is no substantive difference in the generation of wind loads using these provisions, but the limitations on low-rise buildings given in Commentary I-26 vs 4.1.7.6.(1). NBC 2010 said that said that the coefficients are most appropriate for buildings with height/width (H/W) ratios less than 0.5, and must be used for H/W less than 1.0. NBC 4.1.7.6.(1) includes only the 1.0 H/W limitation,

a) Height used to Define Low Buildings

The extensive use of “mid-roof height” in NDS 2015 leads us to believe that is what is intended as H in the H/W ratio. Therefore, the program no longer uses the height you select in the Design Settings to determine this, and always uses the mid-roof height.

This change is made for both NDS 2010 and NDS 2015 design setting selections.

b) Width used to Define Low Buildings

For buildings with varying widths on each level, the program previously determined the width of the structure by taking the largest extent in each direction of any of the levels on the structure, then using lowest value of the NS and EW dimensions so determined. Thus, a structure with a large podium base and a narrow tower would use the base as the width of the structure.

To avoid this situation, the program now uses the average dimension of all levels on the structure in each direction, then the lesser of the two directions.

This change is made for both NDS 2010 and NDS 2015 design setting selections.

c) Warning Messages

Warning messages shown when using the low buildings for H/W ratios between 0.5 and 1.0 have been removed. Those for 1.0 and greater have been modified to show NDS 2015 references.

6. Internal Pressure Coefficient Cpi

In NBC 2010, pressure coefficients Cpi were found in Commentaries I-30 and I-31; in NBC 2015 they are in NBC 2015 4.1.7.7. The three categories for were previously called Category 1, Category 2, and Category 3, but now Table 4.1.7.7. has a column called Building Openings, with the associated Cpi values. The word “category” is no longer used.

a) Input

The Site Dialog input in the Internal Pressure data group is renamed to Openings from Category.

The choices that were previously

 

1. Exceptionally sealed

2. Ord. closed openings

3. Large open openings

 

are now

 

Uniform, small, < 0.1% area

Non-uniform, resistant, closed

Large, often open

 

This change is also reflected in the Site Info echo in the output report.

b) Load Generation Details

In the Load Generation Details report, longer descriptions are given, as follows:

 

Uniformly distributed, small, less than 0.1% of total surface area

Non-uniformly distributed; if significant, wind-resistant and closed

Large, likely to be open during storms

 

C:  Other Wind Load Generation

1. Low-rise Wind Loads for Multiple Blocks and Eccentric Ridge Lines (Feature 26) *edited extensively after first written for 10.2

The method of determining external pressure coefficients CpCg for low-rise structures from NBC 2015 4.1.7.6 and Figure 4.1.7.6.-A (or NBC 2010 Commentary Figure I-7) assumes symmetric, rectangular structures.  They are based on boundary layer wind tunnel studies of buildings of that shape, verified against full scale measurements (NBC Commentary I-20).

As relatively few low-rise structures have such a regular shape, Shearwalls now extends this method to buildings with multiple blocks and/or eccentric ridge lines.

a) Intersecting Blocks

When two blocks intersect such that the slope of a portion of a roof can be formed either by either the side panel of one block or the end panel of the other, such as one roof framing into another to form an L-shape, the manner in which the building is modelled does not affect the wind loads generated because end hip panels are treated as side panels using the other load case.

i. Walls

The area of exterior walls beneath a sloped roof are considered to “have” the slope of the roof for the purpose of Case A (transverse) load generation, which depends on roof angle. If there is a hip end in the Case B (longitudinal) direction Case A coefficients are used on the wall beneath the hip end, the same as the rest of the building face formed by the side of the other block.  

ii. Roofs

A hip end panel in the same plane as a side panel on another block has the co-efficient from the same load case as the side panel, so it is equivalent to the situation where the side panel from one block forms the roof on the entire face and the other block joins that block without forming a hip end.

b) Differing End Panels

Previously the program disallowed structures for which the hip ends on opposing ends of a block had different slopes, or there was a hip on one end and a gable on the other. Now these structures are allowed, and the coefficients used on the roof panels and the walls below the panels are based on the angle of each roof panel.

c) Eccentric Ridge Lines

Previously the program disallowed the case of an eccentric ridge line with different slopes on either side of the ridge. Now this case is allowed, and the coefficients used on the side roof panels and the walls below the panels are based on the angle of each roof panel. This applies to each roof on a structure with multiple blocks.

d) End zones

End zones are created at the ends of each roof block.  This conservatively creates higher end zones loads in areas of the building, such as interior corners and the portion of a building face where one block meets another, that should not experience higher wind loads due to end effects. These loads can be manually edited to have the same value as the non-end-zone loads on that face. It is left as a future improvement to the program to eliminate these extra end zones.

e) Height-to-Width Ratio for Building Limitations

The calculation to determine the width for the height-to-width limitations for this method in NBC 4.1.7.6.(1) considers the maximum extent of all walls on the structure rather than the extent of a single block.

f) Screen Warnings

The error messages that appeared after Generate Loads was invoked saying that load generation was not possible due to unequal hips, eccentric ridge lines, or multiple blocks, have been modified to provide warnings and suggestions for these reasons, but to indicate load generation will proceed.

g)  Load Generation Details

In the Load Generation Details output:

i. Header Note

A note in the header section of the Load Generation Details output indicates that the building does not conform to strictly to NBC 2015 Figure 4.1.7.6.-A or NBC 2010 Figure I-7 for the following reasons, included if applicable to the structure – multiple blocks, eccentric ridge lines, hip roof construction, or unequal hip or gable ends.

ii. Load Table

There are now load tables for each block for multiple block structures, where previously only one table was possible.

h) Torsional Analysis Details

If there are multiple blocks of which any two have orthogonal ridge lines, then both Case A and Case B loads can exist in the same direction on different blocks.  In this case, in the Torsional Analysis Details output where it otherwise says Low-rise Case A or Low-rise Case B, it says Low-rise Case: and then Wind Generally North-South or Wind Generally East-West.

For orthogonal ridge lines, where the section for Case A previously had results for only one load direction, there are now results for both directions.

2. Low-rise Torsional Loads

Previously, Shearwalls analyzed low-rise wind loads from NBC 2010 Commentary Figure I-7 (NBC 2015 Figure 4.1.7.6-A) by considering pressures in the E-W and N-S directions independently and ignored the torsional forces in the orthogonal direction.

However, Note (1) to these Figures says that the building must be designed for “all wind directions”, and that Load Case A and Load Case B are the separate cases for which loads “including torsions” must be generated.

Shearwalls now includes loads due to pressures in both directions in the torsional analysis routine simultaneously, so that torsional forces from E-W loads are considered when determining N-S forces, and vice-versa.

Note that it is only Case B that has simultaneous pressures in both directions.

a) Calculations

In the torsional analysis routine, the program now calculates the torsion T in the equation

 Fti = T Ki li / (Jx + Jy)

as Tx  + Ty for both directions, when previously it Tx  was used for one direction and Ty for the other.  Refer to the Torsional Analysis Details output for the definitions of these variables.

b) Torsional Analysis Details Output

In the Torsional Analysis Details file, for load Case B

-        A note has been added to the top saying explaining the simultaneous design, referring to Note 1 in the Figures.

-        The Concentrated Load F, Center of load Cl and Eccentricity etx values are shown in a table at the top for both directions, rather than separately for each direction. F and Cl now show subscripts for direction, e.g. Fx and Cly

-        The equation of torsions has been modified to show both directions rather than one.

3. Case A Side, Case B End

The program now allows you to show in Plan View the low-rise loads for Case A in the longitudinal direction and Case B in the transverse direction, as these are the cases that will ordinarily govern for design.

a) Single vs. Multiple Block

This option is available only for single block structures, because for a particular wind direction, multiple block structures can have Case A at the end some blocks and Case B for others, and similarly for the sides.

b) Show Menu

The option Case A Side, Case B End appears after the Case A and Case B under Wind Load Case in the Show Menu.

c) Plan View Arrows

The large hollow arrow angled to show the general wind direction has been replaced by two orthogonal arrows in the N-S and E-W directions for this choice.

d) Torsional Analysis

Note that these loads are not to be considered to have been generated simultaneously, and the set of loads shown is not used to generate any torsional analysis case.

4. Show Menus (Bug 3240)

The following changes have been made to the Show menus when Wind design is selected.

a) Orientation

For wind loads, Orientation has changed to MWFRS Direction.

b) Wind Direction

When the Other buildings – 4.1.7.5 wind method is selected, Load Direction is changed to Wind Direction.

c) Wind Load Case

i. Activation When Not Relevant

When the Other buildings – 4.1.7.5 wind method is selected, the wind load case this option is now disabled. Previously the selections were available but had no effect. This happened even when seismic loads were showing.

ii. Case A and Case B Nomenclature

For single block structures, Case A or Case B appear in brackets beside the wind direction, according to the ridge direction of the structure.  

5. Load Generation Details Output

In addition to changes for new or modified features described elsewhere, numerous small formatting improvements and insertions of key information have been added to the Load Generation Details output. The following give the more important changes when NBC 2010 is selected; and the corresponding improvements made using NBC 2015 provision reference numbers when that option is selected.

a) Header and Footer

-       The title, Wind Load Generation, has been set to all capitals to make it stand out from the Seismic Load Generation section that appears later.

-       Add spaces to better delineate the start of the seismic load generation after wind load generation.

b) Site Information

-       Add internal gust factor Cgi, as it is entered in the Site information dialog.

-       Add units (m or ft.), to the hill height, length, and above crest topographic values (Change 242)

c) Legend

-       Add reference to 4.1.7.1.(4) and App. C for velocity pressure q.

-       Clarify that importance factor is ULS (ultimate limit states).

-       Correct reference for Ce from 4.1.7.1 to 4.1.7.1.(5).

-       Clarify that reference heights h come from Commentary I-7(c) as well as I-7(a) and I- 7(b).

-       Give the reference to Figures I-7 for the values of low-rise zone Zn and Windward corner WC.

-       For NDS 2015 option, there are now 2 lines for Cp, one for MWFRS loads and one for C&C loads, showing different design code references.

d) Equations

-       Clarify that C&C wind pressure is from 4.1.7.1.(1) and (3), not just (3).

-       Add the missing factor 0.7 to the equation for rough terrain exposure factor Ce.

-       Add the words “Exposure factor” before the expression for Ce.

e) Load Table

-       Add MWFRS and C&C to the header line of the tables, and remove the repetitive first columns showing these labels. (Change 233)

-       For C&C loads, the mean roof height no longer appears above the table, as it is not relevant to the calculations; instead the value of the reference height h used for Cei calculations is shown, as that had not been output anywhere previously (QA Item 12e).

-       In the low-rise C&C table, the column for internal exposure coefficients Cei was showing 1.0 regardless of the actual Cei value.  It now shows the correct Cei value (QA Item 12a).

-       In the low-rise C&C table, the CpCg column was showing the difference between external CpCg and internal Cpi * Cgi. It now shows just external CpCg as Cpi and Cgi are shown elsewhere in the table (QA Item 12d).

-       The Tributary Height column has been removed for C&C loads, as it has no meaning for these loads and showed random values. (QA Item 64)

6. Bug Fixes and Small Changes

a) Windward Low-Rise C&C Loads (QA Items 12b and 12c) 

For windward low-rise C&C loads program was using the pressure and gust co-efficient CpCg for leeward direction, and internal pressure coefficient Cpi for positive pressures when it should have been using negative pressures. The incorrect coefficients were listed in the Load Generation Details output.

This has been corrected, and different windward and leeward coefficients are created.

For out-of-plane sheathing design, the program now determines the worst case of internal positive pressure and leeward loads, and internal negative pressure and windward loads. As it is only rare cases that the windward loads govern, this had little effect on sheathing design. Nail withdrawal design is not affected.

b) Windward C&C Load Magnitudes (Change 237)

Windward C&C loads were being generated with the same magnitude as leeward ones, i.e., with differing interior and end zone magnitudes. They are now being generated with the correct magnitudes.

Windward C&C loads affect only sheathing design (not nailing), and this change has little design effect as end zone leeward (suction) loads almost always govern design. 

c) Low-Rise MWFRS Pressure/Gust Factor CpCg for Topographic Effect

For low-Rise MWFRS loads with a topographic effect, the program was not including the Cg* component from as per NBC 2010 Commentary I-21, which says you are to multiply CpCg by Cg* and divide by Cg.

It was doing this correctly for C&C loads.

Since Cg* for topographic effect is diminished relative to Cg, this was a conservative bug, and has been corrected for the NDS 2010 design code option. NDS 2015 no longer includes this calculation. 

d) End Zones Under Low-rise Hip Roofs, Case B (QA Item 90)

For walls under hip roof ends using the low-rise procedure and a longitudinal wind direction (Case B), end zones were not being created. This has been corrected.

e) End Zones Under Low-rise Hip Roofs, Case A (QA Item 90)

For walls under hip roof ends using the low-rise procedure and a parallel-to-ridge wind direction wind direction (Case B), end zones were not being created. This has been corrected.

f) End Zones Under Low-rise Hip Roofs, Case B (QA Item 91)

For walls under hip roof ends using the low-rise procedure and a perpendicular-to-ridge wind direction (Case A), end zones were created with a 1-meter width rather than 6 meters, according to 4.1.7.6.A Note 6. This has been corrected.

g) Note for Walls Under Hip Ends (QA Item 90)

The note indicating that hip ends are treated as side panels in terms of low-rise coefficients has been modified to indicate that the walls under the hip ends are also use the same load case as the roof, that is, the one for side panels. A reference to 2001 AWC Wood Frame Construction Manual, Table 2.5A has been added to explain this.

h) Saving of Height Option for b (Change 238)

The Design Setting which is now called Height for Wind Classification is now saved to the project file, it hadn’t been previously. 

i) Hip Roof Options in Load Generation Input (QA Item 43g)

The disabled options for hip roof load generation pertain to the USA version of the program and have been removed completely for Canada.

j) Topographic Factor Above / Below Crest in Site Info (Change 245)

When Below crest is selected in the Site Information dialog box, the Site Location in the Site Information of the Design Results output says Downwind of the crest.  When it is below the crest, it should be Upwind, according to Figure 4.1.7.4, and when it is above the crest, it should be Downwind. This change has been made.

k) Load Generation Log File Wind Load Header (Bug 3084)

n the Load Generation portion of the log file for the All-heights wind load generation method, the line of “------“s was printed at the tail end of the Wind Load Generation header instead of on a new line. This has been corrected for the new implementation in the Load Generation Details file.

l) Wind Direction in Loads and Forces Settings (Bug 3240)

In the Loads and Forces settings, the check boxes labelled Southwest, Northeast, Southeast, Northwest have been changed to show Wind from Southwest, Wind from Northeast, etc.

m) Partial Wind Loading Note

An explanatory note has been added to the Torsional Analysis Details output suggesting manual approaches to implementing load cases B, C, and D from NBC 2010 4.1.7.3 and NBC 2015 4.1.7.9. These cases are not generated automatically by Shearwalls, and would have an effect only on rigid diaphragm torsional forces.

n) Delay in Generating Wind Loads with Topographic Factor (Bug 3251)*

For calculation of the loads that include a topographic factor from NBC 4.1.7.4, the   program was performing the calculation of the Ce, Ce* and Cg* factors at a thousand times as many heights on the surface of the building as was intended, causing a 1-3 second delay when generating loads. This has been corrected.

D:  NBC 2015 – Seismic Load Generation

The changes described in this section occur when NBC 2015 is selected as the design code edition in the Design Settings, unless otherwise indicated.

1. Design for Low Seismic Loads

NBC 2010 4.1.8.1.(1) said that the seismic analysis using the Equivalent Static Procedure was not needed for sites with S(0.2) less than 0.12. This provision has been removed, and replaced with a method in 4.1.3.1.(3)-(15) to be used when a set of conditions for low seismic loading in 4.1.8.1.(2) is met. This method tends to create larger seismic loads than the Equivalent Static Procedure; its advantage is simplicity. It is not implemented in Shearwalls.

a) Message Box

Upon design, a message box used to appear when S(0.2) was less than 0.12, asking you if you wished to proceed with seismic load generation. This has been replaced by a message that informs you of the simplified procedure, its limitations, and that it produces higher loads. the program proceeds to design with the Equivalent Static Procedure.

2.   Seismic Data

The following pertains to the Table C-2 of Appendix C of NBC 2010 and Tables C-2 and C-3 of NBC 2015 that give climatic and seismic data for all significant Canadian towns and cities, which are selected via the default settings in Shearwalls. 

a) Peak Ground Acceleration

The program now includes the values peak ground acceleration (PGA) in the software data as the NBC 2015 Equivalent Static Force Procedure now requires them.

b) Sa(5.0)

The program now includes the spectral acceleration Sa(5.0) as it is now needed to calculate the ratio S(5.0) / S (0.2) to determine higher order factor Mv and overturning factor J. ).  It otherwise corresponds to buildings much higher than those designed in Shearwalls.

c) Spectral Acceleration Values

The values of Sa(0.2), Sa(0.5), Sa(1.0), Sa(2.0) have been changed to correspond to those in NBC 2015. Virtually every value has changed, many significantly.

3.   Site Coefficients F(T) and Design Accelerations S(T) 

This section pertains to the calculation of design spectral acceleration S(T) in 4.1.8.4 Site Properties, which is then used in the Equivalent Static Force Procedure in 4.1.8.11.(2). It is calculated by:

 

NBC 2010:  S(T) = Sa(T) * Fv (Sa(T=1.0), Site Class)

NBC 2015:  S(T) = Sa(T) * F(T, PGA, Site Class)  

 

 where

-        site coefficients F(T), Fv and F are determined from NBC tables,

-        period T is calculated by the program or entered by the user,

-        Site Class is entered by the user,

-        PGA and Sa (T) are seismic data from Appendix C stored for each city and entered either directly or by selecting a city.  

a) Input

PGA, Sa(5.0) and five values of F(T) have been added to the Site Dialog input. The fields Fa and Fv were removed. Like Fa and Fv, F(T)’s are only active for Site class F.

b) PGA ref

The calculation of PGAref = PGA * 0.8 if Sa(0.2) / PGA < 2.0 from 4.1.8.4.(4) has been added.

c) Fa and Fv

As per NBC 4.1.8.4.(7), the program now sets the value of Fa to F(0.2). Although no longer needed in the calculation of S(T), it appears in the expression IEFaSa(0.2) that is still used in many places to classify the structure for the application of various rules, particularly for irregularities.  

Fv is no longer needed by the program.

d) Calculation of S(T)

The calculation of S(T) from NBC 2015 4.1.8.4.(9) is S(T) = Sa(T) F(T), whereas for 2010 4.1.8.4.(7) it was S(T) = Sa(T) Fv

NBC 2015 Tables 4.1.8.4.-B to -E for F(T) have been entered into the program. For tables of F(T) for periods on either side of the actual period Ta, the program determines F(T) based on site class and PGAref, interpolating on intermediate values of PGAref.

Linear interpolation is then used to determine the value of F(Ta), and it is also used to determine Sa(Ta). S(Ta) is then determined via F(Ta) Sa(Ta).

For T < 0.2 s, the NBC 2015 now takes the maximum of F(0.2)Sa(0.2) and F(0.5)Sa(0.5), whereas it used to just use F(0.5)Sa(0.5). This has been implemented.

e) Load Generation Details

In the Load Generation Details output, when NBC 2015 is selected as the design option,

i. Site Information

In the Site Information section which shows the user-input data,

-       Sa(5.0) has been added

-       A line showing F(0.2), F(0.5), etc. has been added if these have been input by the user because it is Site Class F

-       Peak ground acceleration PGA has been added.

-       Fa and Fv have been removed

ii. Legend

-       The definition of Fv has been removed

-       The definition of Fa has been changed, and it is indicated that it is now used for the IEFaSa(0.2) limit

-       A definition of site coefficient F(T) has been added

-       Definitions of peak ground accelerations PGA and PGAref have been added.

iii. Equations

-       An equation for S(T) has been added, which also shows dependencies for site coefficients F

-       An equation for PGAref from NBC 4.1.8.4.(4) has been added

iv. Total Design Base Shear Table

-       A column showing F(Ta) has been added to the table

-       S(Ta) replaces S(T) in heading

4. Disallowed Irregularities for 5-6 Storey Wood Frame Construction

A new provision 4.1.8.10.(4) has been added to NBC 2015 for 5- and 6-storey wood-frame buildings. If the IEFaSa(0.2) product is equal to or greater than 0.35, then Type 4 In Plane Discontinuity and Type 5 Out-of-plane offsets irregularities are not allowed for these structures.

This was already detected and reported by the software following an identical provision in the BC Building Code, so the note under the Seismic Irregularities table has been changed to refer to NBC rather than BCBC.

5. Gravity-Induced Lateral Demand Irregularity Type 9

A new seismic irregularity, Gravity-Induced Lateral Demand, Type 9, has been added to Table 4.1.8.6, with the associated provisions 4.1.8.10.(5)-(7). Note A-4.1.8.10.(5) explains that this corresponds to such elements as inclined columns and floor cantilevers, and involve yielding mechanisms like plastic hinges. This outside the scope of the Shearwalls program and no attempt is made to detect this irregularity.    

a) Design Results Output

This irregularity has been included in the Seismic Irregularities of the Design Results output, giving the design code references, a note explaining why it is not applicable, and a description below the table.

6.  Maximum Base Shear V

The maximum lateral force V calculated in NBC 4.1.8.11.(2)(c) has is now derived from the maximum of two equations as opposed to just one.

a) Calculation of Base Shear

For NBC 2010, the equation is

 

2/3 S(0.2) IE W / (RdRo)

 

For NBC 2015 it is the larger of this equation and

 

S(0.5) IE W / (RdRo)

 

b) Load Generation Details

In the Load Generation Details report (formerly part of the Log file), this equation has been added to the Equations section.

For both the NDS 2010 and NDS 2015 options, the program no longer shows the notes indicating that the maximum shear has been used for design, and instead includes three base shear columns V in the Total Design Base Shear table – Vcalc, Vmax, and Vdes, giving the calculated base shear, the maximum base shear, and which of these has been chosen as the design base shear.

7. Period Ta for Single-storey Wood Structures

A new provision for single-storey wood structures, NBC 4.1.8.11.(4)(a), allows for an increase in the period Ta calculated by the empirical formula in 4.1.8.11.(3)(c) by an amount equal to .004L to where L is the shortest distance between shear resisting elements.

4.1.8.11(c) says that Ta computed using other methods but can’t be greater than 1.5 times that from using 4.1.8.11.(4)(a). This compares to a factor of 2.0 using 4.1.8.11.(3)(c).

a) Calculation of L

L is calculated as the shortest distance between any two shearlines whose extents overlap by one inch or more. The extent of the shearline is defined as the distance between the ends of the extreme shear walls on the line, disregarding gaps in between.  No attempt is made to determine whether shear resisting element extents overlap on a wall-by wall basis.

b) Calculation of Ta

For one-storey structures, the equation 0.05 hn3/4 + L is used for the approximate period Ta.

c) Restrictions on Manually Entered Period

Since this provision is “permitted” and not mandatory, the program checks whether the value input in the Site Dialog is greater than the greater of the two restrictions, that is 2.0 Ta using 4.1.8.11.(3) or 1.5 Ta using 4.1.8.11.(4).

d) Load Generation Details Output

In the Load Generation Details report, for one storey structures,

-       the equation for Ta in the Equations section includes .004L where applicable

-       The expression for Tmax shows the maximum of the two equations

-       A definition of L is given in the Legend.

8.   Higher Mode Effects Mv

The program now includes a calculation of higher mode effects Mv from NBC 4.1.8.11.(6), which is used in the calculation of base shear in 4.1.8.11.(2).

In previous editions of the NBC, all Mv = 1 for all values of period T equal to 1.0 or less, so that no building in Shearwalls could have a non-unity Mv. Table 4.1.8.11 of NDS 2015 has non-unity Mv values for T= 1.0 and values of S(0.2)/S(5.0) > 20. Because a new column bas been added with values of 1.0 for T = 0.5, due to linear interpolation, non-unity values exist for these ratios whenever the period is greater than 0.5.

Since a period of twice the one calculated by empirical formula 4.1.8.11.(3)(c) is allowed by 4.1.8.11.(3)(d)(iii), any height above that corresponding to T = 0.25 using the formula could have a significant Mv. Since that height is 8.5 meters, well below the highest allowable structure in Shearwalls the calculation of Mv in the program is now required. In practice, values of Mv greater than 1.0- will come into play primarily for 5- and 6-storey structures that are newly permitted by NBC.

Note too that ratios of S(0.2)/S(5.0) > 20 for which Mv > 1 occur in numerous locations in Canada.

a) Determination of Mv

The values of Mv are taken from the section for Walls, Wall Frames SRFS from Table 4.1.8.11. Within the range of structures allowed in Shearwalls, these values are identical to those for Other systems.

A separate Mv is determined for each orthogonal force direction, using period Ta and the ratio S(0.2)/S(5.0) to index Table 4.1.8.11. 

i. Interpolation

According to Notes 1 and 2 of Table 4.1.8.11, interpolation should be done on Sa(0.2)/Sa(5.0) first, then on Ta, and Note 2 says to interpolate on S(Ta) Mv, not just Mv(Ta).  So, if we define Sr as the ratio of Sa(0.2)/Sa(5.0), for a Ta between 0.5 and 1.0, we

-       use interpolation on Sr to find Mv( Sr, 0.5 ) and Mv( Sr,1.0 ).

-       calculate the values S(0.5) Mv( Sr, 0.5 ), and S( 1.0 ) Mv( Sr, 1.0 ).

-       interpolate between them to find [S Mv ] ( Sr, Ta ).

-       interpolate S between 0.5 and 1.0 to find S( T),

-       Mv ( Sr, Ta ) = [ S M] ( Sr, Ta ) / S ( Ta ).

b)  Load Generation Details Output

Mv had always been in the Total Design Base Shear table, showing 1.0. The value is now shown to 3 digits precision.

An expression showing the dependencies of Mv has been added to the Equations section, for both NBC 2010 and NBC 2015

9.   Overturning Reduction Factors J and Jx

Although values of overturning reduction factor Jx less than 1.0 were possible for previous editions of NBC, through interpolating between the value of 1.0 for T=0.5  and the non-unity values for T = 1.0, such structures would largely be 5- and 6-storey buildings not previously permitted by NBC. Furthermore, as per NDS 2015 Commentary J-165, J is intended as a corrective to the overestimation of higher mode effects Mv as regards overturning, and Mv was not in previous versions of Shearwalls.

With the introduction of Mv in this version of the software, the overturning effect factors J and Jx have also been implemented.  

As with Mv, non-unity J values occur only for Ta between 0.5 and 1.0, but unlike Mv, the occur for any value of the ratio S(0.2)/S(5.0).

a) Determination of J for Whole Structure

The values of J are taken from the section for Walls, Wall Frames SRFS from Table 4.1.8.11. Within the range of structures allowed in Shearwalls, these values are identical to those for Other systems.

A separate J is determined for each orthogonal force direction, using period Ta and the ratio S(0.2)/S(5.0) to index the table.   

As per to Notes 1 and 3 below the table, interpolation is done on Sa(0.2)/Sa(5.0)  first, then on Ta.

b) Storey Factor Jx

For each level, and in each direction, a story factor Jx is determined using NBC 4.1.8.11.(8):

 

Jx = 1.0 when hx >= 0.6 hn

                   Jx = J + (1 – J) hx / 0.6 hn when hx < 0.6 hn

hx is the height at the top of level x, and hn is the mean roof height.

c) Hold-down Forces

All hold-down forces on a particular level and direction are multiplied by the factor Jx for that level and direction. This is because hold-down forces in Shearwalls are derived from the formula Mx / L, where Mx is defined as in 4.1.8.11.(8) and L is the wall segment length.  

d) Output

i. Load Generation Details

In the Load Generation Details report:

-       definitions J and Jx have been added to the legend

-       an expression showing the dependencies for J has been added to the Equations section

-       The formula for Jx has been added to the Equations section

-       A column for J has been added to the Total Design Base Shear table

-       Columns for Jx in each direction have been added to the Distribution of Base Shear to Levels

ii. Hold-down Design Table

The value of Jx is shown for each shearline in the Hold-down Design table. A definition appears in the legend beneath the table.

iii. Elevation View

Jx is shown in the Factors section of the legend in Elevation view.

10. Base Shear Increase for User-input Ta for 5- and 6-Storey Buildings

A new provision in NBC, 4.1.8.11.(12), calls for a 20% increase in base shear for 5 and 6 storey structures for periods determined using 4.1.8.11.(3)(d), i.e., “other established methods of mechanics using a structural model”, most commonly Rayleigh analysis.

As an increase in T results in reduced base shear, we assume that whenever you over-ride the period determined using the empirical equation 4.1.8.11.(3)(c) by entering a larger one in the Site Dialog input, 4.1.8.11.(3)(d) is being used and the 20% surcharge is applied.

A decrease in the period is assumed to mean that you are just adjusting the height used in 4.1.8.11.(3)(c), as no advantage is accrued.

a) Calculation

For each orthogonal direction independently, if the period Ta is greater than that calculated by the empirical equation 4.1.8.11.(3)(c), a factor 1.2 is applied to the calculation of base shear V in     

b) Load Generation Details Output

When applied, the equation for V shown in the Equations section of the Load Generation Details Output includes the 1.2 factor. In the unusual case that it is applied in only one orthogonal direction, two equations are shown for V, one for each direction.

11. One-storey Buildings with Large Diaphragm Deflection

A new provision in NBC, 4.1.8.15.(4) for single-storey structures with a wood roof diaphragm and with Rd greater than 1.5, requires magnification of deflections and/or design forces if the diaphragm deflection exceeds ½ the storey drift of the adjoining shear walls. This affects only large structures with a large sufficient distance between shearlines to create large diaphragm deflection.

As Shearwalls does not currently calculate diaphragm deflections, a warning is displayed for structures of a size that is susceptible to this condition.

a) Detection of Condition

The check for this condition is made before loads are generated. For single-storey structures only, if the Rd value is greater than 1.5, the program will determine, in both directions, the shortest distance between shear-resisting elements, using the same algorithm as given above. For imperial units, if the distance is greater than 100 feet, and for metric, 30 metres, the building is considered susceptible. 

b) Warning Message

If the condition is detected, a Yes, No, Cancel message box asks you whether you want to change Rd to 1.5. The actions taken are

Yes – Change Rd to 1.5 and generate seismic loads.

No – Continue to use the existing Rd and generate seismic loads

Cancel – Don’t generate seismic loads  

E:  Other Seismic Load Generation

1. Period Restriction on Irregular Structures

The program previously assumed that there would be no periods greater than 0.5, so the program did not check for the condition Ta > 0.5 or disallow irregularities of Type 1-6 as per 4.1.8.7.(1)(c).

However, a period of twice the one calculated by empirical formula 4.1.8.11.(3)(c) is allowed by 4.1.8.11.(3)(d)(iii), so any height above that corresponding to T = 0.25 using the formula, or 8.5 meters, could have a Ta > 0.5. In practice, 5- and 6-storey structures now supported by Shearwalls often do have periods in this range when calculated using methods such as the Rayleigh quotient.

The following applies if Irregularities Type 1, 2 ,3, 4, 5, or 6 exist and if IEFaSa(0.2) >= 0.35:

a) Irregularity Table Failure Column

if T >= 0.5 in the direction(s) for which the irregularity exists, the shearlines and direction(s)s that have these irregularities appear in the “Fails for” column.

b) Table Warning

If T >= 0.5 in at least one direction for which the irregularity exists, a red warning message appears above the table indicating that design has failed due to the irregularity.  The message saying that the program does not check for T > 0.5 has been removed.

c) Screen Warning

If T >= 0.5 in at least one direction for which the irregularity exists, a screen warning message appears indicating that design results are not valid.

d) Notes

Notes appear below the table indexed to the irregularities saying that seismic design is not allowed using the Equivalent Static Procedure when T > 0.5, and it is if it is less than or equal to 0.5. 

e) Design Summary

If T >= 0.5 in at least one direction for which the irregularity exists, it triggers the note in the Design Summary saying that at least one irregularity violates design code provisions.

2. Vertical Stiffness Irregularity Type 1

The program now detects the Type 1 Irregularity – Vertical Stiffness, which occurs when the lateral stiffness of a storey’s SFRS less than 70% of that of an adjacent storey, or 80% of the average of the three storeys above and below.   

a) Detection

In each direction, for both rigid and flexible diaphragms, the program determines the stiffness of all wall segments on the level using the same procedure by which it determines the stiffness for Irregularity 4 – In Plane Discontinuity. It will then sum all those stiffness values.

If the stiffness on any level is less than 70% of the stiffness on the level above or below, than the irregularity exists.

For those levels with 3 storeys either above or below (levels 1 and 4 in a 4- storey structure; 1, 2, 4, and 5 in a 5-storey structure, and any level in a 6-storey structure), the program determines average of the 3 storeys either above or below the level, and if stiffness on the level under consideration is less than 80% of that value, the irregularity exists.

b) Irregular for..

For the adjacent level stiffness, the Irregular for… column in the Seismic Irregularity Table shows the level with the reduced stiffness followed by the stiffer level e.g. 3,4.

For the average of 3 levels, it shows the reduced stiffness followed by the stiffer levels as e.g.  4,1-3

The Direction shows E-W, N-S, Both, or None

c) Fails for…

If there is a weight irregularity and T>=0.5 for at least one direction, and IaFaSa(0.2) >= 0.35, the storeys appear in the Fails for column

d) Notes

The note saying it is irregularity detection is not required for because it is not a post-disaster building has been removed.

The existing notes about the relevance of IEFaSa(0.2) >=  0.35 or < 0.5 and T < 0.5 are included when irregular. If T >= 0.5 a new note says that Equivalent Static Procedure is not allowed.

e) Design Not Valid Warnings,

If irregular, T >= 0.5 in at least one direction, and IEFaSa(0.2) >=  0.35, a screen warning message appears indicating that design results are not valid, a red warning message appears above the Irregularities table, and the Design Summary says that at least one irregularity violates design code provisions.

f) Description

The description of the irregularity below the table gives the 70% rule and 80% rules and explains the table columns.

3. Weight (mass) Irregularity Type 2

The program now detects the Type 2 Irregularity – Weight (mass), which occurs when a level is 1.5 x more massive than an adjacent non-roof level, or a roof is 1.5 x as massive as its adjacent level.

a) Detection

Table 4.1.8.6 refers to a storey, which is defined in NBC Division A, 1.4.1.2 as the distance from the top of one floor to the top of the floor above it. The roof is considered a separate storey.

On the other hand, the levels that are defined for apportioning seismic load are defined from the middle of the wall on one level to the middle of the walls on the level above. A roof is considered part of the upper level.

For irregularity detection, the program collects all the masses that are tagged as being on level 2, for example, but come from the lower portion of level 3, and includes them as storey 3 loads. It excludes masses from the roof and gable ends, which are on the uppermost level, from the upper storey, and creates a separate storey for these. 

For multi-block structures, for mass from roofs on blocks with fewer levels than the highest block, the roof is added to the mass of the level above the highest storey on the block. For example, if Block 1 has 2 storeys and block 2 has 4 storeys, a roof on block 1 will is part of level 3.

Flat roofs and ceilings are part of the uppermost storey of the block they are on, not the roof level. 

Snow masses are not included among the weights for this purpose.

b) Irregular for…

The Irregular for… column in the Seismic Irregularity table shows the heavier storey followed by the light storey, e.g., 3,4. The direction is always Both. If a heavy roof is one of the storeys, the word “Roof” is used.

c) Fails for…

If there is a weight irregularity and T>=0.5 for at least one direction, and IaFaSa(0.2) >= 0.35, the storeys appear in the Fails for column

d) Notes

The note saying it is irregularity detection is not required for Ta less than 0.5 has been removed. The existing notes about the relevance of IEFaSa(0.2) >=  0.35 or < 0.5 and T < 0.5 are included when irregular. If T >= 0.5 a new note says that Equivalent Static Procedure is not allowed.

e) Design Not Valid Warnings,

If irregular, T >= 0.5 in at least one direction, and IEFaSa(0.2) >=  0.35, a screen warning message appears indicating that design results are not valid, a red warning message appears above the Irregularities table, and the Design Summary says that at least one irregularity violates design code provisions.

f) Description

The description of the irregularity below the table gives the 150% rule, defines a storey, and explains the table columns.

4. Re-evaluation of Discontinuity Irregularities Types 3, 4, and 5

Research into the intention of NBC 2015 4.1.8.15.(5) (NDS 2010 4.1.8.15.(4)) has inspired a re-evaluation of the approach taken by Shearwalls to this provision. This clause states that elements supporting a discontinuous wall are to be designed for forces equal to the lateral capacity of the SFRS components they support rather than calculated forces. The intention is to protect the gravity force resisting system from forces due to lateral loading, for example a lintel above an opening that supports vertical element such as a column carrying a hold-down force at the end of a discontinuous shear wall on the level above the opening. In such a case, the column, lintel, hold-down, and other connections are to be designed using the capacity of the discontinuous wall.

a)  Relevant Irregularities

Shearwalls previously applied this irregularity for Irregularities Type 3 - Vertical geometric, Type 4 - In-Plane Discontinuity (offset), Type 4 - In-Plane Discontinuity (stiffness) and Type 5 - Out-of-plane Offsets,  The rationale for Types 3 and 5 was that a discontinuity must exist somewhere for these irregularities to exist, and for Type 4 - In-Plane discontinuity (stiffness) that the NBC 2010 Commentary J-205 (NBC 2015 J-208) referred to Type 4 irregularities in general.

Shearwalls now applies this provision only for Type 4 - In-Plane Discontinuity (offset) and Type 5 - Out-of-plane Offsets. Shearwalls detects an in-plane offset whenever wall ends do not line up on adjacent floors, which is exactly the type of discontinuity this provision is meant to address. Type 5 discontinuities occur when there is no wall below a wall on the level above, which also creates a discontinuity at wall ends.

Stiffness irregularities are irrelevant to the intent of this item so Type 4 - In-Plane discontinuity (stiffness) is no longer included. And although Type 3 - Vertical geometric implies a discontinuity must exist somewhere, it is a general, statistical check which cannot be used to identify where action must be taken. If Type 3 exists, then a Type 4 or Type 5 must also exist somewhere, so the situation will be handled without the need to include Type 3 in the solution.  

b) Weak Storey

The program previously reported a failure due to these irregularities if the capacity of the entire SRFS on the floor below the one with the discontinuity was less than the capacity of one with the discontinuity. This was based on a misconception and has been removed from the program.

The program no longer includes discontinuous shearlines in the Fails for column of the Seismic Irregularities table for this reason, nor does it issue screen warnings for this failure or place a red failure message above the table. The notes below the table have also been modified. 

c) Strengthening of Hold-downs

When an irregularity was detected, the program automatically used shear wall capacity as the design hold-down force on all shear walls on both the level with the irregularity and the level below. This is an overly conservative approach, and this automatic procedure has been removed from the program until we can develop an algorithm to identify and strengthen only those hold-downs that require it.

d) Strengthening of Drag Struts

When an irregularity was detected, the program automatically used shear wall capacity as the design drag strut force on all shear walls on the level below. Instead, the program should add the additional force due to capacity-based design on the floor above as a surcharge to the diaphragm shear force used to calculate drag struts on the floor below. The automatic strengthening of drag struts has been removed until we can develop such a procedure.

e) Design Iterations

The need to identify irregularities to apply the automatic strengthening of hold-downs and drag struts necessitated an additional iteration of force distribution and design in Shearwalls. This has been removed, which should lead to somewhat faster design results.

f) Warnings and Notes

All screen warnings have been modified to indicate that you must manually strengthen hold-downs and drag struts at specific locations, rather than informing you that the program has done so. The notes below the Irregularities table have been similarly modified. 

g) Design Settings

The asterisk beside the Design Settings Drag strut / Hold-down forces based on … Applied loads has been removed, along with the note saying that shear wall capacity is used for discontinuities as per 4.1.8.15.(4).

5.   Deflection Analysis for Detection of In-Plane (stiffness) Irregularity Type 4

Due to the non-linearity in the nail deformation term of the equation for deflection for shear wall deflection from 11.7.1.2, shear wall stiffness decreases as applied force increases. As a result, Shearwalls previously identified a Type 4 In-Plane Discontinuity (stiffness) in NBC 4.1.8.6 based on a lower-storey shear resisting element having less stiffness than an upper storey one even when walls on the two storeys had identical construction.

As structural analysis for most materials assumes a linear stiffness relation v = K δ, where v are forces, δ deflection, and K a constant stiffness matrix, we do not believe it was the intention of NBC 4.1.8.6 to consider identically constructed storeys as having differing stiffness. The program therefore uses the 3-term linearization of the deflection equation introduced in this version (see G: 1 below), to determine the deflections for Type 1 - Vertical Stiffness and Type 4 – In-plane Discontinuity (stiffness) irregularity detection. It does so even when the non-linear 4-term equation is used for deflection analysis for force distribution and storey drift.

a)  Design Iterations

If you have selected the 4-term deflection equation option in the design settings (the default), an additional design iteration will be inserted before the existing iterations, using the 3-term deflection equation, for the purpose of detecting Type 1 and Type 4 (stiffness) irregularities. Another iteration is then performed for final design of the shear walls using the non-linear 4 term equation, during which all other irregularities are detected.

b) Tolerance

Testing revealed that small, unwanted differences in stiffness still occurred for identical shear walls on adjacent levels. A comparison tolerance of 1% was added which eliminated these occurrences.

c) Description of Irregularity

The description of the Type 4 – In-plane Discontinuity (stiffness) irregularity beneath the Irregularity table has been modified to reflect this procedure.

6. Irregularity Table Changes

a) Irregularity Names

Irregularity names in the Irregularity table have been modified to conform more closely to the nomenclature in Table 4.1.8.6.  In screen messages they have been expanded to show a less abbreviated name, and in the descriptions below the Irregularities table, the full name as it appears in Table 4.1.8.6 is shown.

b) Format of References

The format of references to NBC provisions in the table has been modified to conform to NBC protocol, e.g., 7-1c is now 7(1)(c).  Compound references change from e.g. 10-1,2b to 10(1),(2)(b).

Also changed comma between two Sentence references to a semi-colon, to distinguish from comma between Clauses.

c) Detected by Column

The Detected by column has been removed as all relevant irregularities are now detected by the program. 

d) Type 6 Irregularity Message (QA Item 52)

The screen message indicating an Irregularity 8 was detected referred to an IESaFa(0.2) value of 2.0 when it should have been 0.2. This has been corrected.

e) Weak Storey Irregularity 6 Notes (QA Item 78n)

The notes pertaining to Weak Storey Irregularity Type 6 have been reorganized and improved, giving references to NBC 4.1.8.10.(1) and 4.1.8.10.(2)(b).

f) Post Disaster Note (QA Item 78o)

A reference to NBC 4.1.8.10.(2)(a) has been added to the note about post-disaster buildings.

g) NBC References for IEFaSa (QA Item 78l)

The notes that include IEFaSa(0.2) >= 0.35  or < 0.35 N now include references to NBC 4.1.8.7.(1)(a), 4.1.8.6.(3) and Commentary J-122.

h) Commentary Reference for Type 7 Irregularity (QA Item 78d)

NDS 2010 Commentary J-156 (NBC 2015 J-150) has been added for Type 7 Irregularities. 

i) Commentary Reference for Type 7 Irregularity (QA Item 78e)

NDS 2010 Commentary J-207 was a mistake; it has been changed to J-205.  

j) Commentary Reference for Type 7 Irregularity (QA Item 78h)

NDS 2010 Commentary J-127 was a mistake; it has been changed to J-128. 

k) Commentary Reference for Type 7 Irregularity (QA Item 78i)

NDS 2010 Commentary J-177-9 was a mistake; it has been changed to J-171-3. 

7.   Disallowed Irregularities for 5- and 6- Storey Structures

A new provision 4.1.8.10.(4) has been added to the NBC disallowing Irregularities Type 4 In Plane Discontinuity and Type 5 Out-of-plane offsets for 5- and 6-storey structures when IEFaSa(0.2) >= 0.35.

This had already been implemented in Shearwalls based on an identical provision in the British Columbia Building Code (BCBC). The note at the bottom of the Irregularities table and the screen message that appears for this condition have been updated to refer to the NBC and remove references to British Columbia.

8.   Load Generation Details Output

In addition to the changes to the Load Generation Details output described elsewhere due to new or changed features, numerous small formatting improvements and insertions of key information have been made. The following gives the more important changes:

i. Header

-       The title, Seismic Load Generation, has been set to all capitals to make it stand out from the Wind Load Generation section that appears earlier.

ii. Site Information

-       Removed the words Regular Structure. This was not intended to be in the Canadian version and appeared even when the structure is irregular

-       The spectral accelerations Sa(0.2), Sa(0.50), etc., have been placed on one line for compactness, rather than each one occupying its own line.

-       Similarly, for the NBC 2010 option the Fa and Fv values have been placed on one line, and they are now shown only for site class F (when they are input by the user).

-       The importance factor Ie is now shown only when input by user for hazardous category.

iii. Legend

-       Reorganize table to put long descriptions all on left side so that the table fits within a printed page.

-       The definition for T now says it is in seconds (s).

-       Remove SRFS from the definition for Rd

-       The definition of hn now says that it is the top level, not just “level n”

-       For subscripts x, “level analyzed” is used instead of “level x”

-       For subscripts i, the word “levels in sum” is used instead of “level i”

iv. Equations

-       The units, (N, m) have been added to the title of the Equations section indicating the assumptions used when calculating the equations. These units are always metric regardless of what is used to display the output values. 

-       Removed the unit reference for the height hn used for T, as units have been added to the table heading

-       Design code reference numbers have been added for all the equations

-       An equation for Vmax has been added (NBC 4.1.8.11.(2)(c))

-       For the NBC 2010 option, an expression showing the dependencies of S(Ta) has been added

-       An expression showing the dependencies for RdRo has been added (NBC 4.1.8.9)

-       An expression for Ta max has been added (NBC 4.1.8.11.(3)(d)(iii))

-       The maximum Ft value is now indicated (0.25 V)

v. Total Design Base Shear Table

-       The table has been renamed Total Design Base Shear, from Calculation of the total design base shear:

-       The data are now displayed in a tabular format with headings, rather than as repeated symbols, equal signs, and values.

-       Units have been added to the title of the table showing the system used for the data displayed, which unlike the units for the Equations table can be metric or imperial and show kN rather than N.

-       Fa and Fv values are now shown beneath the table, as they are ordinarily calculated by the program and not user input. Fv appears only for the NBC 2010 option

-       The importance factor Ie is now shown beneath the table, as it contributes to the calculation and is not ordinarily input by the user.

-       Removed information about distribution of loads to the levels from note about manually entered seismic loads and forces.

vi. Distribution of Base Shear to Levels Table

-       Distribution of total design base shear to Levels has been changed to Distribution of Base Shear to Levels

-       In the table heading, the words Height and Weight have been changed to the symbols hi and Wi, which are defined in the legend

-       The information about top level Ft has been moved from a note at the top of the table to be a separate line in the table

-       Numbers are now right-justified so decimal places line up, and trailing zeros are no longer truncated.

-       Added note about distribution of manually entered seismic loads and forces.

9. Bug Fixes and Small Improvements

a) Importance Factor Input for Hazardous Category (Bug 2718)

The Importance factor in the Site Information dialog for Hazardous importance category, which is a value you can override due to Commentary J-110, would revert to the default value of 1.3 when the Site Parameters Dialog was re-opened. This value was then used for design unless it is changed.

This has been corrected and the input of importance factor now persists.

b) Seismic Irregularity Type 6 Failure Criterion (QA Item 65)

The program was basing the failure criterion of Seismic Irregularity Type 6 – Weak Storey on a value of IEFaSa(0.2) > 0.12 when it should have been 0.20 as per 4.1.8.10.(1). 

c) Seismic Irregularity Type 7 for Post-Disaster Buildings (QA Item 69)

Seismic Irregularity Type 7 was not amongst the irregularities that provoked a failure due to NBC 4.1.8.10.(2).(a) for post-disaster structures, but it should be. This has been corrected.

d) Show Menus (Bug 3240)

i. Wind Load Cases

When seismic loads are selected, the Wind Load Case options are now disabled. Previously the selections were available but had no effect.

ii. Force / SFRS Direction

The Force Direction item has been renamed SFRS Direction, for consistency with the change to MWFRS for wind. SFRS stands for Seismic Force Resistance System

iii. Load / Force Direction

The Load Direction input has been renamed Force Direction, as the shearline and hold-down forces are the only things that could potentially change when an opposing direction is selected. Note that it is very rare that seismic forces differ in opposing directions and this set of options usually has no effect.

 

F:  Load and Force Distribution

1. Sign Convention for Torsional Analysis

In the Torsional Analysis Details file, distances such as center of load, center of mass, shearline location and eccentricity have been based on a fixed co-ordinate system with its origin in the southwest corner of the structure. S->N distances are positive, and N->S are negative.

 The forces F, however, are based on the direction of applied force; for N->S applied force, all values in the N->S direction are positive; for S->N applied force, they are negative.

Some users find this confusing and wish to see all values relative to the same fixed co-ordinate system. Other users, however, wish to see positive shearline forces when they are in the direction of the applied force, and this corresponds to the way they are presented in the Plan view drawing. 

Accordingly, we now offer a choice in the Options settings of showing forces based on a fixed co-ordinate system, or relative to the applied force.

2. Torsional Analysis Details Output

In the Torsional Analysis Details output report (previously part of the Log file)

a) Accidental Eccentricity References

In the Torsional Analysis Details, the references to accidental eccentricities have changed:

-       For flexible diaphragm seismic, it was J 178 from a previous design code edition, and is now J-172 for J NBC 2010 and J-178 for NBC 2015.

-       For rigid diaphragm seismic, it mistakenly showed a wind reference, and now shows NBC 4.1.8.11.(11) for 2015 and NBC 4.1.8.11.(10) for 2010.

-       For rigid diaphragm all heights wind, it said just 37 for 2010, now it is I-37. For low rise wind for 2015 it refers to NBC 4.1.7.9.(1)(a) and A-4.1.7.9.(1) Case A      

b) Headers

i. Repeated Header Line (Change 236)

When wind loads only were on the structure, the torsional analysis section of the log file output had a repeated header line. The new Torsional Analysis Details file shows only one header in this case.

ii. Wind Load Subheading Under Flexible Seismic (Change 240)

A sub-heading for wind loads mistakenly appeared under flexible seismic design. It has been removed.

c) Flexible Seismic Explanation (QA Item 3a)

It has been made clear that the explanation of the Fti calculation is an example in one direction only.

d) USA ASD Reference (Change 239)

A note referred to ASD load factors, which is a USA term. This has been corrected.

e) Concentrated Load Terminology (QA Item 45a)

The term Concentrated Load F has been changed to Total Load F, as the load is not concentrated at a location. 

3. Bug Fixes and Small Improvements

a) Nonsensical Hold-down Forces under Monoslope Gable End (Bug 3217)

When a wall was underneath a gable end from a monoslope roof, the hold-down forces calculated were nonsensically large. This has been corrected.

a) Shearwalls have Equal Rigidity Setting

The Design setting under Shearwall rigidity per unit length…  for Shearwalls have equal rigidity has been removed from the program, as it does not correspond to any physical situation. It is a vestige of the original, less sophisticated implementation of torsional force distribution and is no longer needed. 

a) Force Distribution due to Unsorted Openings (Bug 2099) 

Occasionally, after a complex set of user interface operations, wall openings could become unsorted internally and skew the distribution of forces on the shearline, also affecting shearwall design. This has been corrected.

b) Nonsensical Output of Diaphragm Force (Bug 3185)

Occasionally, one of the diaphragm force Fpx values in the Seismic Information table would show a nonsensically high number. This was a rarely occurring bug due to unusual configurations of program memory, and has been corrected.

c) Show Menu Items for Center of Load and Center of Rigidity (Change 251)

The show menu items for center of load and center of rigidity were always disabled in Loads and Forces view, only becoming active in Load Generation view. This has been corrected and they are active in both views.

d) Center of Loads for No-load Cases (Change 251)

When there are no loads in a direction, such as for low-rise wind load Case A, the program showed the Center of Load in the direction without loads at the zero location, making it difficult to notice. In this case, it has now been moved to where the Center of Rigidity is located.

e) Overlapping Center of Load and Rigidity Symbols (Change 251)*

When the center of loads and center of rigidity are in the same place or close to it, the symbols CL and CR now longer overlap.

 

G:  Deflection Analysis and Shear Wall Design

1. 3-term Linearized Deflection Equation (Feature 211)

Shearwalls now offers the choice of using the 4-term deflection equation in CSA O86 11.7.1.2 and a 3-term linearization of this equation. The linearization follows a formulation in the AWC Special Design Provisions for Wind and Seismic, equation 4.2-1, for shear wall deflection analysis in the United States.

a) Background

The 3-term equation is a linearization of the 4-term equation, arrived at by combining the shear and nail slip equations in the 4-term equation using an “apparent” shear stiffness Ga.  The linearization is achieved by setting the non-linear occurrences of shear force v to the shear capacity of the shear wall to render them constant. It is therefore identical to the 4-term equation when the shear wall is at capacity, conservative when below capacity, and non-conservative for shear walls that are overstressed for design anyway.

The 3-term equation can be preferable because the process of equalizing deflections on the shear wall segments by adjusting the forces apportioned to each segment sometimes does not converge due to the non-linearity of the 4-term equation, whereas the 3-term equation always converges to a solution. Furthermore, using the 4-term equation, Irregularity Type 4 – In Plane Discontinuity (stiffness) from NBC 4.1.8.6 is detected for adjacent storeys even if they are constructed of identical materials (see E: 5 above). 

b) Design Setting

A Design Setting called Linearize deflection equation has been added to allow you to choose between these two methods It is recommended to choose Never, but switch to Always if using the deflection-based force distribution method and one or more of the shearlines do not show the same deflections on each loaded shear wall segment in the line.

Note that the choices of Always and Never have been chosen to allow the future implementation of a hybrid design for which we allow the program to automatically change from 4-term to 3-term on individual shearlines if non-convergence is detected, especially using flexible distribution; however, for Version 10, the switch must be made manually and for all shearlines in the structure.

Mixing the two methods in the same design could adversely influence force distribution based on relative stiffness. This is true within a line, and possibly distribution to shearlines if the rigid distribution method is used, so further research is needed before a hybrid approach is attempted.

c) Deflection Calculation

The following terms in the two-term equation

 

  

 

are replaced by

 

i. Ga Calculation

The calculation of Ga for wind design uses the formula

 

 

 

0.75 is the serviceability (SLS) importance factor for wind design, and 1.4 is the load combination factor for wind design, IW is the ultimate limit states (ULS) importance factor for wind design. These factors are needed to adjust for the fact that deflections use SLS forces but shear walls are at capacity for ULS forces. Ls is the shearwall segment length.

For seismic design,

 

       

Conversion between SLS and ULS load factors is unnecessary, as they are all 1.0; only the ULS importance factor IE differs.   

ii. Unblocked Factor

The unblocked factor Jub is applied only to the v value in the main deflection equation. not the vs and vw values in the calculation of Ga. Dividing v by Jub is equivalent to factoring the whole shear stiffness Ga by Cub.

iii. Non-linear Anchorage Equation

CSA O86 has a further non-linearity to those in the main deflection equation in 11.7.1.2, the elongation for anchorages, which is

 

       Analogous to the procedure for calculating Ga, this is

 

 

 

d) Deflection Convergence

Using the linearized setting, the program is always able to equalize deflections for all segments on a wall, except those cases that there is not sufficient loading to allow the same deflection to be achieved in some segments as for other segments in the line that have a relatively high constant deflection due to factors such as gypsum wallboard nail slip. This happens only for lightly loaded shearlines.

e) Stiffness Irregularity Detection

Even when you choose not to linearize the equation for load distribution and storey drift, the linearized equation is used for the detection of Type 4 Vertical Discontinuities (stiffness) irregularities. Refer to E: 5 above for more d Using the linearized setting, the program is always able to equalize deflections for all segments on a wall, except those cases that there is not sufficient loading to allow the same deflection to be achieved in some segments as for other segments in the line that have a relatively high constant deflection due to factors such as gypsum wallboard nail slip. This happens only for lightly loaded shearlines.

f) Output

If the Design Setting option to linearize deflections is chosen, the Deflection table shows only one deflection value called Shear defl, rather than separate shear and nail slip deflection. The Ga value is also shown, and the Vn and en values for nail slip show the values at shear wall capacity vs or vw used to calculate Ga

The legend at the bottom of the table has been modified to reflect these changes.

2. Hold-down Database Update (Feature 202)

The database of hold-down connections has been updated to conform to the Canadian Limit States Design version of the Simpson Strong-Tie Wood Construction Connectors Catalogue, page 83, as of January 17th, 2018. This is found at http://embed.widencdn.net/pdf/plus/ssttoolbox/oknkjgclgk/C-C-CAN2018.pdf.

3. Design Results Output

a) Design Settings Table

i. Relative Rigidity Formatting

For consistency with other cells containing phrases rather than numeric data, Shearwall relative rigidity and Design shearwall force/length are now in sentence case rather than title case.

b) Shearline, Wall, and Opening Dimensions Table

i. Aspect Ratio (Feature 77)

The aspect ratio (shear wall height / length) of each shear wall segment is now shown in a column in the table next to the full height sheathing. It is defined in the table legend.

ii. Wall Order

Occasionally, walls would appear out of order in the table. This has been corrected.

ii. Dash Justification

The dashes that appear for fields that do not contain data are now center justified. (QA Item 24a)

f) Sheathing and Framing Materials Tables

i. Grade/Ply (QA Item 75c)

The table header Grade/Ply has been changed to Mark/Ply, as the OSB Table 9.3C with grades no longer exists. The legend item below has also been changed

ii. Mark/Ply Legend Item

In the Mark/Ply (formerly Grade/Ply) legend item (QA Items 75a and 75b)

-       Removed obsolete reference to table 9.4D

-       Refers to plywood plies and OSB panel mark, not just “mark” and “plies”.

-       “see” note 8 is not “shown in” note 8

iii. Panel Mark in Note (QA Item 75e)

The words panel marking have been changed to panel mark in the note below the table.

iv. Numbered vs. Non-numbered Notes (75d)

The list of notes without numbers has been differentiated from those with numbers, with the former headed by General Notes: and the latter by Material-specific Notes.

c) Design Summary

i. Percentage Gypsum Note for 5- and 6- Storey Structures (QA Item 27)

The note about compliance with O86 11.8.8 which disallows gypsum contribution for 5- and 6-storey structures was mistakenly replaced with one about Rd and Ro values. This has been corrected.

ii. C&C Non-shearwall Nail Withdrawal Failures in Design Summary (QA Item 28)

When C&C nail withdrawal design failed for non-shearwalls, the Design Summary said under capacity walls were found but did not list them. This has been corrected.

d) Seismic Information Table

i. Reference in Seismic Information Warning Message (Change 248)

The words CSA O86 have been added to the reference 11.8.3.2 about overcapacity ratio under the seismic information, as most seismic provisions are from NBC, and there are no nearby references to O86.

e) Shear Design Table

i. Order of Wall Rows (Bug 2116)

Shearwalls were not always listed in order as they occur from west to east or south to north. This has been corrected.

f) Components and Cladding Table

i. Table Legend

The table legend has been improved to

-       add design code clause references,

-       correct typos,

-       clarify when end zone or suction pressures are used,

-       say that 24” spacing with vertical panels uses 2-span sheathing bending analysis.

g) Hold-down Design Table

i. Order of Hold-downs (Bug 2116)

Hold-downs were not always listed in order as they occur from west to east or south to north. This has been corrected.

ii. Wind Direction in Legend

The word wind has been removed from wind direction in the table, as it was appearing for seismic design as well as wind.

h) Drag Strut Table

i. Order of Drag Struts (Bug 2116)

Drag struts were not always listed in order as they occur from west to east or south to north. This has been corrected.

i) Deflection Table

i. Legend O86 Reference  

The word O86 has been placed before the first design code reference from the CSA O86.

j) Hold-down Displacement Table

i. Rounding of Elongation Values (QA Item 29a)

The hold-down elongation values and possibly other values in the table were not always being rounded to the nearest 1/10 of a millimeter, but rounded to the 1/10 value in the other direction. This has been corrected.

4. Bug Fixes and Small Improvements

a) Tolerance in Equalizing Deflections (Change 227)

Occasionally, warnings appeared indicating the program had not equalized deflections on the shear line when the Design Results output showed identical deflections along the line.  This was because the tolerance for equalizing deflections internally was 0.01% of the deflection value, which is unnecessarily stringent. It has been changed to 0.5%, which ensures that when deflections are not equalized to that level, it is apparent in the output table.

b) Nail Withdrawal Force for C&C Design (QA Item 101a)

The C&C load for nail withdrawal design was the highest of all storeys on a shearline rather than the load on the level of the wall being designed. This has been corrected.

c) Selection of Nail Diameter for Interior Wall Surface (Bug 3218)

In wall input view, the program did not allow input of nail diameter for the interior side of a wall. For power driven nails with multiple possible diameters, this meant that the program selected a diameter at random for design. For all other nails, selection of nail length uniquely determines the diameter so there was no problem.

It is now possible to select nail diameters for both sides of the wall.

g) 1.2 Drag Strut Factor (Change 250)

The 1.2 drag strut factor from CSA O86 11.8.6 was being applied regardless of the value of IEFaSa (0.2) when according to 11.8.1 Drag struts = 1.2 (11.8.6) in the Elevation view legend always appeared regardless of whether this factor was applied. It now only appears for high seismic zones when the 1.2 factor also appears for the “S” component of hold-down forces.

h) Shear Stiffness Bv for Unknown Sheathing Thickness (Bug 3269)*

When determining the shear-through-thickness Bv from O86 tables 9.3A – C used in the shear term of the deflection equation in 11.7.2, when the sheathing thickness had been left unknown, the program was using the Bv for the thickest sheathing option, or 23/32”, rather than the thickness for the sheathing being designed. This caused a non-conservative error in the shear term of the deflection equation of about 5%. The shear term is usually a small component of the overall deflection.

d) Dead Load Contribution to Hold-down Forces for Rigid-Only Design (Bug 3153) 

Hold-down forces components due to dead loads were not created when designing for rigid diaphragm forces only, that is, when flexible diaphragm analysis is turned off in the Structure view. These force components did not appear in the Hold-down Design table or in Elevation View, and the deflection analysis and design of hold-downs did not include the counteracting effect of dead loads. This has been corrected.

e) Wall Groups for Unknown Power-Driven Nails (QA Item 88) 

When power driven nails are selected with unknown as the diameter, the program wasn’t determining the worst case of seismic, wind, rigid and flexible design for the nail diameters so that extra wall groups corresponding to the nails designed for each of these criteria were generated, and appeared throughout the design results. This has been corrected.

H:  Elevation View

1. Zoom and View Settings (Feature 216)

You are now able to zoom Elevation View in and out and to establish view settings similarly to Plan View.

a) Elevation View Setting Tab

A tab for Elevation View has been added to the Settings box, with similar inputs to the View tab for Plan view.  The setting previously called View has been changed to Plan View.

i. View Area

You can establish the confines of your viewing area with the View area inputs or change them using the Zoom buttons in the Elevation View data bar. 

ii. Fit Building to Viewing Area and Fit Viewing Area to Window

These settings act similarly to Plan View, allowing you to recapture the full image of the structure after it has been zoomed.

iii. Plan View Snap Increment

Since there is no interactive input in Elevation View, the snap increment entered in the Plan View settings is shown here, and is used as the metric for the Display gridlines input.

iv. Display Gridlines

You can now display gridlines at a different interval from how they are shown in Plan view using this input.

v. Zoom Increment

You can set the percentage by which the image expands or contracts each time the Zoom in and Zoom out buttons in the Elevation View data bar are pressed.

b) Toolbar Buttons.

Zoom in and Zoom out buttons in the Elevation View data bar expand or contract the image by a percentage increment entered in the Elevation View settings.

c) Mouse Wheel

It is also possible to zoom the image via the mouse wheel, owing to the new feature described in I: 1 below.

2. Multi-storey Selected Walls (Feature 230)

You can now choose to view Selected Walls while viewing multiple levels or multiple levels while in Selected Walls mode.  In this case, the program shows only walls that are above and below the selected walls. This allows you to view see the entire vertical load path for a single stack of walls. Previously, it was difficult to do so for long shearlines because the data tended to overlap. 

a) Data Bar Controls

Previously, when Selected Walls was chosen in Elevation view, the levels control was disabled.  Now it is enabled.

b) Drawing

When in Selected Walls mode while more than one level is being viewed, the program uses the walls on the level selected in Plan view to determine what walls are shown on other levels. It shows all walls on other levels that are entirely within the extents of the selected walls.

If contiguous selected walls are selected, the program shows walls on other levels within the total extent of the contiguous walls, even if they do not lie within the extent of any one of the selected walls. However, if there is a gap between selected walls, the program does not show walls on other levels that lie even partially within that gap.

If you find this difficult to envision, just experiment with the program.

3. Shading of Non-shear-resisting Segments (Feature 56)

The following elements are now shaded in light gray to indicate that they are not considered shear resisting elements.

a) Shearwall segments

Within shearwalls, segments which are too narrow to be considered full-height segments, and are this not included in design and do not draw force, are shaded. 

Openings are shaded above and below the opening.

b) Non-shearwalls

Non-shearwalls are shaded except for the openings. 

4. Dimension Lines (Feature 79)

Dimension lines indicating the length of full-height segments or of perforated walls, opening length and height, joist depth and wall height are now shown in Elevation View.

a) Display Settings

In both the Show menu for Elevation View, and in the Display data group of the Options settings there is a checkbox to turn off the display of dimensions for walls and for openings independently. Joist thickness is also turned off when walls are turned off.

b) Location of Dimension Lines

i. Full Height Segments and Perforated Walls. 

Full height segments in all shear walls and entire non-shearwalls are dimensioned in the bottom area of the wall.

ii. Openings

The horizontal dimension of openings is shown on top of the opening if there is room, otherwise within the opening.

The vertical dimension of openings is shown inside the opening on the right-hand side.

iii. Wall Height and Joist Thickness

The wall height is dimensioned to the left of the entire shearline, and the joist thickness to the right. 

c) Format

Dimensions are in feet or meters, and you can control whether feet-inch or fractional feet, and whether fractional inches are shown, using the Imperial Format setting for Distance

5. Display of Roof Line and Gable End (Feature 228)

a) Display Settings

In the Show menu while in Elevation view and the Display data group of the Options Settings in the Elevation view column, items have been added for the display Gable end and for Roof.

When Roof is checked, the gable end is always shown, and its checkbox is disabled and checked.

i. Gable End

This setting controls the display of the triangular gable end of the wall. If the setting Ceiling acts as upper level diaphragm is checked in Structure view, this portion of the wall is not considered part of the shear wall, and turning off the setting economises on space without compromising the depiction of forces on the line.

ii. Roof

This setting controls the display of side panels and hip ends, which do not affect the distribution of forces within the shearline, so this setting can be turned off to economize on space if only the forces within shear walls are of interest.

b) Gable Ends

Gable ends are part of the end wall, and it was previously unclear whether they were considered part of the shear wall, as they are if Ceiling acts as upper level diaphragm is unchecked in Structure view.

i.   Wall drawing

If selected for display, gable ends are drawn in the same green colour as the wall.  

ii. Force arrows

When Ceiling acts as upper level diaphragm is unchecked in Structure view the program draws the arrows for the diaphragm shear force and the segment shear forces along the slope of the gable end rather than at the level of the top of the upper storey.

These force locations are used in the calculation of the moment arm for hold-down force calculations, however previously that was not apparent. 

If you choose not to draw gable ends, then the forces are drawn along the top of the upper-level wall at eave height, even though they act at the height of the sloping roof.

c) Hip Roof and Side Panels

Hip roof panels and side panels are drawn in a mid-gray colour, and the entire outline of the panel is drawn, including the line at eave height. 

The panels are drawn only if the roof block edge is collinear with the wall, in other words, if the roof is made of rafters, the wall supports the rafters.

Roof panels are drawn only for those blocks whose highest level corresponds to one of the levels selected in Elevation view.

6. Segment Numbers (Feature 77)

a) Display Setting

In the Show menu and in the Display data group of the Options settings, you can now turn on and off the display of segment numbers. By default, they are off.

b) Segment Number

In the upper portion of shear wall segment, centered horizontally, the program shows the segment number after the wall number, e.g. A-1,1; A-1, 2; etc.

c) Critical Segment

Within the design results text below the drawing, the program now gives the critical segment, e.g. A-4,2, in which 4 is the wall number and 2 is the segment number. Previously it just indicated the segment was within wall A-4.

7. Bug Fixes and Small Improvements

a) Placement of Segment Shear Force Values (Feature 79)

For multi-storey structures, the numeric value of the shear force on each segment has been raised above the arrows for the design shear force on the storey above, if they would otherwise be obscured by them or by the diaphragm itself. 

b) Crash for Offset walls with Dead Loads (Bug 3138)

For shear walls offset from the shearline location, and if dead loads were on the wall, the program was crashing when Elevation View was viewed. This has been corrected.

i) Selected Walls from Multiple Shearlines (Bug 3167)

When individual walls from different shearlines were selected in Plan view, Elevation view in the Selected Wall mode showed all these walls, even if they overlap. Now the program shows only the walls from the first shearline selected, as it does when multiple entire shearlines are selected when in Entire Shearline mode.

j) Disabled Level Input in Elevation View (Bug 3172)

After re-entering the Structure action or Roof action in Plan View are selected, then going to Elevation View, the Level input was disabled, and you were unable to change the levels being viewed. This has been corrected.

k) Drawing of Offset Walls (Bug 3175)

When walls on a shearline are offset in plan from neighbouring walls, in Elevation view the offset walls were drawn slightly than normal, causing a small gap between walls. This occurred consistently when viewing one level and occasionally when viewing multiple levels, and has been corrected.

l) Rescaling after Disabling Material Information (Bug 3177)

After disabling the framing, nailing, or sheathing information under the shear walls in Elevation view, it did not rescale to accommodate the change in information. This resulted in you being unable to see the information when it was re-enabled, or the view having a large amount of blank space along the bottom when the information was disabled. These problems have been corrected.

m) Vertical Elements (Change 223)

It is now possible to turn on and off vertical elements via the Show menu in Elevation view. 

I:  Plan View

1. Mouse Zoom (Feature 219)

The program now zooms the drawings of the structure via the mouse wheel. Previously this could only be done via toolbar buttons.

In Plan View and for the new zoom feature for Elevation view, when the Control key is depressed, each click on the mouse wheel expands or contracts the image by percentage increment given in the View settings, like one push on the zoom button.

2. Wall Depiction in Plan View (Feature 56)

a) Non-full-height Segments

All shearlines with aspect ratios that are too narrow for design given the selected Design Settings are now shown with a white interior and coloured border the same as a non-shearwall, as they are effectively non-shearwall segments.

b) Legend

A legend below at the bottom of the screen shows the markings for Shearwalls and Non-shearwalls.  

3. Design Case in Plan View (Feature 83)

The program now indicates explicitly Plan View whether you are viewing seismic or wind loads, which wind load method, and the force distribution method (rigid or flexible diaphragm). Previously you had to infer this information from the arrow style, existence of large low-rise arrows, and other clues.

a) Loads and Forces View

In the line in the legend previously starting with Loads shown W or Loads Shown E it now shows,

 

Loads: Low building Wind (W); Forces 1.4W + 0.9D; Flexible distribution

Loads: Any building Wind (W); Forces 1.4W + 0.9D; Flexible distribution

Loads: Seismic (E); Forces 1.0E + 1.0D; Flexible distribution

 

b) Loads Generate View

Where it previously said Unfactored generated shear load, the program now says, for NBC 2015

 

Unfactored generated wind load using NBC 4.1.7.6 for low buildings (plf)

Unfactored generated wind load using NBC 4.1.7.5 for any building (plf)

Unfactored generated seismic load (plf)

 

For NBC 2010 it is

 

Unfactored generated wind load using NBC Fig. I-15 for any building (plf)

Unfactored generated wind load using NBC Fig. I-7 for low buildings (plf)

 

4. Bug Fixes and Small Improvements

a) Gap in Building Footprint for Openings Extending to Wall End (Bug 3142)

Following a specific sequence of wall input steps, it was possible to create a gap in the exterior footprint, rendering the project file unusable.

This occurred when an opening was than extends to the very end of a wall, meeting a perpendicular wall. If the location of the wall with the opening is then moved, followed by moving the wall it meets, the gap is created.

This problem has been corrected.

b) Zoom Buttons in Fit Building to View Area Mode (Bug 3170)

In Plan View, when Fit Building to Viewing Area is active, the zoom buttons on the toolbar were disabled, because the building no longer fits the viewing area when zoomed.

However, this view option is the default, so it was often unclear why the zoom buttons were disabled. For this reason, the zoom buttons now remain enabled, and their use deactivates the Fit Building to Viewing Area setting.

This behaviour is also adopted for the new feature of zooming and Fit Building… for Elevation view. 

J:  Program Operation

1. Separate Torsional Analysis and Load Generation Output

The output report showing intermediate calculations for load generation and for torsional analysis has been split into two separate files, one for load generation and the other for torsional analysis.  

a) Toolbar buttons

The toolbar button that previously showed the word log and is called Load Generation and Torsional Analysis Details has been replaced by two buttons, one which shows three arrows and is called Load Generation Details, and another which shows a semi-circular arrow and is called Torsional Analysis Details. These buttons are adjacent to the existing button for Detailed Shearwall Design.  

The button for the primary design results has been changed to convey the tabular nature of that output.

b) Operation

Previously, the combined file was output when loads were generated, then appended to after Design button was pressed when the torsional analysis is performed. If loads were then regenerated, the torsional analysis results were lost. Other synchronization problems occasionally occurred.

Now, the Load Generation Details file is output when loads are generated and Torsional Analysis Details when the design is performed, eliminating any interference between the two.

c) Headers

The titles and headers to the load generation and torsional analysis results have been redesigned to achieve a consistent format across all three intermediate output files, torsional analysis, load generation, and shear wall design.

d) Getting Started Steps

The 14th and final step in the introductory Getting Started window has been modified to refer the Torsional Analysis Details, Load Generation Details, and Detailed Shearwall Design output reports rather than the log file.

2. Settings

a) Hold-down Setting Input Field Sizes (Change 244)

Sime of the inputs in Wood Properties and Construction Details section of the Hold-down settings were too small to show typical data without scrolling, and have been enlarged.

b) Activation of Imperial Formatting on Change of Unit System (Change 246)

In the format Settings when changing from Metric to Imperial units, the Imperial Formatting input remained disabled. It is now active immediately upon changing to Imperial.

n) Format Settings Typo (Change 221)

In the list of Imperial format choices in the Format settings, the examples were prefaced by "e.g." rather than "e.g.", the correct spelling. This has been corrected.

c) Display Settings Names (Change 231)

The word “table” has been removed from several Options Settings in the Display design results group, as it had been inconsistently applied to some design results tables and not others. The setting that previously said Materials table now says Sheathing/framing materials; in all other cases the word “table” has just been excised.

d) Reset Original Settings for Cities in Default Settings (QA Item 84a)

After clicking the Reset original settings button in the Default Values settings page, the default province was correctly set to British Columbia, but the list of cities showed those in Ontario instead of British Columbia, with the default being Kincardine rather than Vancouver (City Hall).  If you then then select a city from the list the wrong velocity pressures were selected.

These problems have been corrected.

e) View Setting Nomenclature

The following changes have been made to the data field labels in the View settings, which area now shown in separate Plan View and Elevation View boxes:

i. Mouse Click Interval (Change 225)

The word intervals has been changed to snap increments for consistency with the nomenclature in Display Gridlines, which uses the term snap increment.  For Display gridlines, Snap has been changed to snap.

ii. Save to Project File (Change 226)

An asterisk (*) has been placed beside those inputs that are not saved to the project file, with an explanatory note at the bottom of the box. These inputs are the zoom increment and the Fit Building… and Fit Window… settings.

3. Bug Fixes and Small Improvements

a) Crash on Input of Standard Walls (Bug 3202)

After restoring all Standard Walls to the ones that originally came with the program using the Default Values setting, the program crashed if there were any standard walls that you had made being used in the project.

Shearwalls now only allows the standard walls to be reset if there are no open documents.  If you attempt to reset them with a document open, the program now prompts you to close the open document.

b) Levels Indicator for One-storey Structure (Change 249)

For a one-storey structure, the Levels indicator is shown in the Extend to field. Now it is shown in the Current level and the Extend to field is invisible in this case.

c) Error Message for Ceiling Depth (QA Item 14)

Upon inputting the ceiling depth above level 6 in Structure input view, a Windows “improper argument” message appeared. This has been corrected.

d) Spelling of C&C (Change 222)

Changed all instances of C & C to C&C in the Show menus, Load Input view, drawings, and output.  Also changed End Zone to End zone and Load to load.

e) Show Menu Groups (Change 224)

Added a separator to the Elevation View Show menu separating the options dealing with graphical elements such as wall names with those dealing with design results text. 

f) Wall Segment Nomenclature (Change 243)

The title of the section of wall input view giving the hold-down configuration, location, now says e.g., Wall A-1 rather than Wall segment A-1. The inputs are for an entire wall, including openings and possibly several segments, not for an individual shear wall segment. 

 

Shearwalls 9.3.2 – December 8, 2015 – Design Office 9, Service Release 3a

Note that this service release also includes the change listed for version 9.3.1, which was a hot-fix version distributed only to the user who reported the problem.

1. Boundary Element Stud Sizes (Bug 3111)

The following problems with the boundary element stud sizes occurred when imperial units were selected, appeared in the Framing Materials table of the design summary output and affected the calculation of A in the equation for deflection from O86 11.7.1.2.

They also created problems in terms of identifying walls with similar attributes, so that duplicate standard walls and wall design groups were created. These problems have been corrected.

a) Nominal vs. Actual Units for Stud Sizes

If a non-standard (custom) stud width or depth was entered, then a standard width or depth reselected, the program was using the nominal value of the standard width or depth (e.g. 6.0”) when it should have been using the actual width (e.g. 5.5”). 

b) Custom Stud Sizes

After saving a project with non-standard (custom) stud widths or depths, upon reloading the file the size of the width or depth was the value of the width or depth in mm. rather than inches.

2. Hold-down Force Increase for High Seismic Force (Bug 3116)

The program was implementing O86 11.8.2, the increase in hold-down design force by 20% for high seismic zones, only if Shearwall capacity is selected for Hold-down force based on...  in the Design settings. It is now implemented regardless of whether this setting is selected.

3. Perpendicular Direction Load Distribution from Manual Area Building Masses (Bug 3099)

Starting with version 8.1, manually input area building masses were creating a point seismic load in the direction defined by the start and end of the building mass, as well as the line seismic load in the perpendicular direction representing the distributed area mass in that direction.

The point load does not correspond to the actual distribution of mass and has been removed. In its place, there is a line load representing an area mass originating at the location of the building mass, and extending the tributary width that was input for the building mass. The tributary width used to create this load is the length of the input mass.

4. Absence of Failing Walls in the Design Summary (Bug 3112)

If at any point in designing a shear wall, the program rejected a possible wall because it did not meet the ductility criterion, then if the wall finally selected failed because of insufficient shear wall capacity, it did not appear in the Design Summary page listing all failed shear walls.

The ductility criterion, from O86 11.8.1, is that in order to ensure ductility, the critical failure mode for the wall is mode d, e, or g from O86 12.9.4.2.

 

Shearwalls 9.3.1 – December 2, 2015 – Hot Fix

1. Seismic Mass from Interior Non-Shearwall Shearlines (Bug 3094)

The building masses created from interior shearlines composed entirely of non-shearwalls were not used to create seismic loads, nor was the mass included in the calculation of total mass of the structure for base shear calculations. This has been corrected.

 

Shearwalls 9.3 – September 11, 2015 – Design Office 9, Service Release 3

This service release provides design for CSA O86-14 standard, as well as allowing continued use of CSA O86-09.  The following is an index of links to changes described in more detail below.

 

A: CSA O86-14 Design Standard. 2

1. Choice of Design Standards. 2

2. Design Code Clause References. 2

3. On-line Design Code. 2

4. Program Information. 2

5. Design Code References. 2

6. Vrs Calculation. 2

7. Nail Types and Sizes. 2

8. Gypsum Underlay. 2

9. Nail Slip for Deflection en 2

10. Gypsum Wallboard (GWB) Design. 2

11. Service Condition Factor KSF. 2

B: Other Engineering Design. 2

1. Unit Nail Resistance Nu for Anchorage Deflections. 2

2. Shearwall Capacity Hold-down Method in the Calculation of Deflections (Bug 2999) 2

3. Non-standard Nail Diameters (Bug 2664) 2

4. Wind Load Storey Drift Table (Bug 3032) 2

5. Standard Walls and Design Groups. 2

6. Special Seismic Checks in Design Summary (Change 220) 2

7. Message Box for Gypsum Wallboard Rd Factor 2

8. Percent Resisted by Gypsum Table. 2

9. "Improper Argument" error for OSB Sheathing (Bug 3012) 2

10. Elevation View Failure Message for Passing Walls (Bug 3007) 2

11. Both Direction Output in Storey Drift Table (Bug 3018) 2

12. Moisture Conditions Label (Change 217) 2

13. Moisture Conditions Description in Input and Output (Change 218) 2

14. Extra Null Lines in C&C Design Table (Bug 3035) 2

15. Plan View Legend Wording for Failed Walls (Change 177) 2

C: Loads and Forces. 2

1. Duplicate and Missing Low Rise Wind Loads (Bug 3002) 2

2. Centre of Mass and Center of Rigidity in Plan View (Feature 218) 2

3. C&C Wind Loads in Both Directions (Change 176) 2

4. Crash Upon Input of C&C Load (Bug 176) 2

5. Update of Add Load Dialog Input (Bugs 3005, 3077) 2

6. Missing Elevation View Forces in for No Deflection Analysis (Bug 3003) 2

7. Missing Snow Load Note in Load Generation Dialog (Bug 2988) 2

8. Nonsensical Torsional Forces in Log file for Low Rise Wind Design (Bug 3006) 2

9. Multi-block Low Rise Height to Width Setting (Change 183) 2

10. Site Information Output 2

11. Load Generation Details Results in Log File. 2

D: Materials. 2

1. OSB and GWB in Wet Service Conditions (Bug 3000) 2

2. Plywood Sheathing Plies (Bug 2994) 2

3. Custom Plywood Thickness (Bug 2994) 2

4. Nail Penetration Imperial Unit Format (Change 180) 2

5. Nail Diameter Format (Change 219) 2

6. MSR Grade Design Note (Change 215) 2

7. OSB Panel Marking Design Note (Change 216) 2

E: Program Operation. 2

1. Extend Upwards Operation (Bug 3073) 2

2. Settings Dialog for Medium and Large Display Size (Bug 3068) 2

3. “Getting Started” Steps Display (Change 181) 2

4. Main Toolbar (Change 197) 2

5. WoodWorks Sales and Technical Support Contact Information (DO Change 6) 2

6. Parentheses in the Help About box (DO Change 7) 2

7. Apply Button in Settings Dialog (Change 185) 2

8. Update of Roof Overhang Input (Change 186) 2

9. Image File Wording in Message (Change 182) 2

10. Typo in Out-of-date Design Message Box (Change 178) 2

 

A:  CSA O86-14 Design Standard

1. Choice of Design Standards

The program now implements the new CSA O86-14 Engineering Design in Wood Standard. As the National Building Code referencing CSA O86-14 is not yet released, and provincial building codes have not yet mandated the use of O86-14, the program also allows you to continue using CSA O86-09.

Input

a) Design Code Selector

A drop list box called Design Code has been added to the Design settings in the Design procedures data group, with the choices

 CSA O86-09/ NBC 2010

 CSA O86-14/ NBC 2010

b) Output

The Design Settings output has been changed from showing only the National Building Code edition to showing CSA O86-09 / NBC 2010 or CSA O86-14 / NBC 2010.

c) Program Information

It shows the edition of the O86 currently being used, and the fact that it is the May 2014 printing of the CSA O86-14, in the About Sizer box accessed from the Help menu and in the Building Codes box accessed from Welcome Box. In the main body of the Welcome box, it indicates that either of these codes can be used.

2. Design Code Clause References

a) Update to 2014

The references to the CSA 086 design code clause numbers in the input forms and screen messages, and in warnings, design notes and other program output, have been updated to show the 2014 edition clause numbers when CSA O86-14/ NBC 2010 is chosen as the design setting. It continues to show 2009 edition numbers when CSA O86-09/ NBC 2010 is chosen.

b) On-line Help

The on-line Help has been updated to refer to the CSA O86-14 design code clauses. The unrevised online Help is also included in the installation to allow you to use Help that references O86-09.

3. On-line Design Code

The Design Office installation the on-line 2014 edition of CSA O86 in .pdf form has been made available. program now allows you to view either the CSA O86-14 or CSA O86-09 design code, and both documents are included in the Design Office installation.

4. Program Information

The Welcome box now indicates that both design codes are available. The Help About Shearwalls box and the Building Codes box show information about the currently selected design code.

a) 5- and 6 Storey Provisions

The Building Codes box and the message that appears when you enter more than 4 storeys have been updated to refer to the 5- and 6- storey provisions in the NBC 2015 rather than the BC Building code. Information about continuous hold-down systems and rotational deflection required for taller structures has been added to the Building Codes box

b) Wood Shrinkage and Irregularities

Information about wood shrinkage and irregularities not considered has been removed from the Building Codes box. 

5. Design Code References

In all messages, notes, warnings, and output tables, the program shows design code clause numbers for either O86-14 or O86-09, according to which is selected.

 

The rest of the changes described in this section occur when CSA O86-14 is selected as the design code edition in the Design Settings, unless otherwise indicated.

 

6.  Vrs Calculation

For wood-based structural panels, the program now calculates Vrs via the expressions in O86 11.5.1:

φ vd JD ns Jus Js Jhd Ls (lateral nail resistance)

φ vpb KDKSKT Ls (panel buckling)

The worst case of these two equations is determined for each side of the sheathing, and then the two sides are summed. 

Previously only the expression

             Φ vd KDKSF Jub Jsp Jhd Lw

was used.

The following subsections apply to wood-based panels only; the procedure for gypsum wall board has not changed.

a) Vhd calculation

The calculation of Vhd, which is just Vrs without the Jhd factor, for use in determining the Jhd factor, considers both the lateral nail resistance and the panel buckling equations, despite the fact that Jhd appears only in the nail resistance equation. (This was decided upon after consultation with the design standard authorities.)  The procedure for combining sides is thus:

-        determine worst case Vhd (nailing) vs. Vrs (panel buckling) on each side

-        combine the sides to calculate Jhd

-        take Vrs nailing = Vhd * Jhd on each side

-        take worst case Vrs (nailing) vs. Vrs (panel buckling) on each side

-        combine the sides again

b) Resistance Factor φ

The resistance factor φ has increased from 0.7 to 0.8, the value that has always been used for nail resistance, for both panel buckling and nailing equations.

c) Vrs due to Nailing Strength

Vrs from O86 11.5.1(b) is calculated as follows:

i. Vd calculation

Unit lateral Vd is now calculated via the equation Nu/s, where Nu is the factored unit lateral nail strength in N from O86 12.9.4.1 and s is the edge nail spacing, rather than tabulated values based on sheathing thickness and nail sizes.

The notes to O86 09 9.4.4 representing strength adjustments for special cases are no longer applied.  

ii. Impact on Nail Selection

Nu varies continuously according to nail length, diameter, and penetration depth, whereas Table 9.4.4 provided only a very limited number of choices, conservatively specifying a minimum nail diameter for which the tabulated values were valid, and a required penetration depth.

This means that the choice of nail size has a much bigger impact than before; the program has added more nail sizes and types to the program as described in J: 8 below.

iii. Nu Factors

Nu from 12.9.4.1 is given by nu KSF KD KT, with the K factors implemented as follows.

1. Service Factor KSF

The service condition factor KSF comes from O8612.2.1.5 for connections. The same service factor is applied to all walls in the structure based on the in-service and fabrication conditions input in the Design Settings. Green fabrication or wet service conditions correspond to moisture greater than 19%.

For changes in the service factor input, terminology and calculations, refer to J: 13 below.

2. Duration Factor KD

This is set to 1.15 for both wind and seismic. It does not represent a change from the previous version.

3. Treatment Factor KT

As the factor for studs is one unless they are incised there is no program input of treatment factor and KT = 1, always.

iv. nu calculation

nu is calculated by the yield mode equations in 12.9.4.2. The following inputs correspond to a single shear plane plywood-to-stud connection:

1. Side member thickness t1

This is the sheathing thickness in mm.

2. Nail diameter d

As input in Wall Input view.  

3. Stud embedment strengths f2, f3

Determined from density of stud and nail diameter.

4. Penetration length t2

Nail length minus the sheathing thickness.  The ability to include gypsum wallboard underlay in the sheathing thickness has been added because of its effect on nail penetration – see J: 9 below for details.

5. Nail yield strength fy

Determined from nail diameter.

6. Structural panel embedment strength 

Determined from density of sheathing material (CSP, DFP, or OSB), and nail diameter.

v. Ductility check

According to 11.8.1, to ensure ductility, the wall should fail in modes d, e, or g from 12.9.4.2.

For each wall design or candidate design for unknown parameters, the program will record whether the lowest value of the nail failure modes for either side of the shear wall is not d, e or g.

If a completely specified wall, or for a failed wall arrived at when all unknown possibilities are exhausted, fails because of the ductility check, the symbol # appears beside the wall capacity in the shear results table and a note below the table indicates a design failure and the reason.

The program passes over candidate designs for which the ductility check fails. If the program cannot find a design, and at least one wall that had sufficient capacity was rejected because of nail ductility, the symbol @ appears by the wall capacity and a message below the table informs you what happened.

vi. JD Factor for Diaphragm and Shear Wall Construction

This factor is always set to 1.3.

vii. Number of Shear Planes nS

As mid-panel shear walls are not to be included in this version, the value of ns is always 1.

viii. Unblocked Factor Jus

The nomenclature for this factor has changed, but in terms of engineering design there have been no changes to program.

ix. Spacing Factor Js

This factor is implemented according to O86 11.4.1, a formula based on panel edge spacing.  It is less than one for spacing less than 150 mm, and equal to one for larger spacing.  

d) Vrs due to Panel Buckling Strength

Vrs from O86 11.5.1(c) is calculated as follows:

i. vpb Calculation

The following parameters are used in the equation for specified panel buckling strength vpb:

1. Axial Stiffness Ba,90, Ba,0

The axial stiffness values Ba,90, Ba,0 from tables 9.3A ,9.3B and 9.3C for each plywood or OSB thickness, and no. of plies for plywood and panel marking for OSB, have been added to the program. The value Bv was already in the program for use in deflection analysis.

For both Ba and Bv, if you enter a larger sheathing thickness value than is in the dropdown list, but one in table 9.3A-C , the correct value for that size from 9.3A-C is used. Previously, for Bv the program used the value from the largest thickness in the dropdown list.  If you type in a larger thickness than is in the table, the input is rejected with a warning. 

2. Panel Sizes a,b

As the buckling resistance gets larger as the smallest dimension of the sheet used gets smaller (because of the “b” in the denominator of the vpb equation the critical panel), the critical panel within a segment is the largest one. Therefore, full 4 x 8 sheets are used for those segments that are larger than 4 feet wide for vertical sheathing and 8 feet for horizontal orientation. For smaller segments, the size of the largest component panel is determined, for example a 6-foot segment uses 4’ x 6’ for horizontal sheathing and 4’ x 8’ for vertical. A segment 3 feet wide uses 3 x 8 for vertical and 3 x 4 for horizontal.

ii. Service Condition Factor KS

For wet service conditions as input in the design settings, the program uses KS from Table 9.4.2 and applies factor of 0.80.  Wet fabrication conditions to not apply to plywood.

Note that wet service conditions are no longer allowed for OSB or gypsum wallboard, see M: 1 below.

iii. Treatment Factor KT

Due to the rarity of use of treatment factors for plywood and OSB, the program does not include an input for treatment and this factor is always 1.0.

iv. Duration Factor KD

This is set to 1.15 for both wind and seismic.

e) Design Results Output Tables

i. Shear Design Table

In the Shear Design table, the total force on the wall or segment Fv and the corresponding capacity Vr have been removed from the table to make room, and because they are not particularly useful to the designer.

Where the table previously had one unit capacity Vhd/L, it now shows unit capacities for nail resistance and panel buckling separately, headed by Vhd (vd) / L and Vrs (vpb) / L, respectively. The table shows values for interior and exterior sheathing sides for each.  The combined Vrs/L is still shown.

Corresponding changes have been made to the explanatory legend below.

ii. Framing Materials Table

The Jsp column and legend entry have been removed from the Framing Materials table, as it no longer applies for O86-14.

iii. Sheathing Materials Table

In the Sheathing Materials table, the Jub heading and legend description have changed to Jus.

f) Design Notes

Design notes appear below the Sheathing Materials table that indicate sheathing and nailing requirements, and adjustments to strength for particular configurations. The following changes have been made to these notes:

i. Blocking Requirements

Added design code references 11.4.4 and 9.4.4 for 086-14 and O86-09, respectively.  Added sentence saying unblocked panels must be staggered.

ii. Nailing Requirements

Added design code references 11.5.3.4and 9.5.3.4 for 086-14 and O86-09, respectively.  Cleaned up character spacing issues. 

iii. Framing and Panel Requirements

Added design code references 11.5.3.2 and 9.5.3.2 for 086-14 and O86-09, respectively.  Changed “wide” to “thick” to make stud dimension clearer. Show metric or imperial thicknesses according to units selected.  Cleaned up character spacing issues.

iv. Shear Strength Upgrade for Stud Spacing 400 mm or Less

This is Note 1 or Note 2 in Shearwalls, and is from the asterisk (*) under O86-09 Table 9.5.1A.  This note has been removed for the O86-14.  Minor formatting improvements for 09.

v. Double Studs at Panel Edges for 50 mm Edge Nailing

In Shearwalls, this is Note 3 for O86-09 and Note 1 for O86-14, and is from the symbol Ɨ  under O86-09  Table 9.5.1A.  Show metric or imperial thicknesses and nail spacing according to units selected. For imperial, say “minimum 3-by or double 2-by”.  Add 11.5.3.5 a reference for O86-14.   Minor formatting improvements.

vi. Double Studs at Panel Edges for 75 mm Edge Nailing and 3.66 mm Nails

In Shearwalls, this is Note 4 for O86-09 and Note 2 for O86-14, and is from the symbol ǂ  under O86-09  Table 9.5.1A.  Shows metric or imperial thicknesses and nail spacing according to units selected. For imperial, say “minimum 3-by or double 2-by”.  Added 11.5.3.5 b reference for O86-14.   Minor formatting improvements.

vii. Staggered Panel Edges on Opposite Sides

In Shearwalls, this is Note 5 for O86-09 and Note 3 for O86-14 is Note (3) under O86-09 Table 9.5.1A.  Add 11.5.3.5 reference for O86-14.   Minor formatting improvements were also made.

viii. Jn Factor for Non-Standard Nails

In Shearwalls, this is Note 6 for O86-09, and has been eliminated for O86-14, as there is no Jn factor. 

ix. MSR Grade

In Shearwalls, this is Note 7 for O86-09, and has been eliminated for both design codes. Refer to M: 6 below for more details.  

x. OSB Panel Marking

In Shearwalls, this is Note 8 for O86-09 and Note 4 for O86-14. Add design code references 11.5.3.3 and Table 9.5.1A Note 6 for 086-14 and O86-09, respectively. Fixed problem with panel marking output, refer to M: 7 below, (Change 216).

g) Detailed Design Results

Upon design, the program outputs a new file containing intermediate design data, called [projectname].swd. A menu item and toolbar button each called Detailed Shearwall Design access this file and show it in a reader similar to the one showing the Load Generation and Torsional Analysis log file.

i. Symbols

The output starts with a table showing all the symbols used in the equations governing shearwall design and shown in the headers for the tables in this file.  Each line shows the symbol, definition, two columns for units employed, and the reference to the O86-14 clause where the symbol is defined or used. 

The first unit is for those that appear in the equations as published in the O86, and the second one is for the units that are shown in the tables below. For imperial units, the first set will be metric and the second set imperial. For metric units, the columns usually show the same units, except for cases that the table shows for example kN rather than N for formatting convenience.

ii. Equations

The symbols are followed by a section showing the equations employed, along with the design code clause reference for each one.

iii. Constant Data

There are two lines of data that are the same for all shear walls. The first line shows data that can’t be changed by the user, the second shows ones that can, or may be in future versions of the software. These lines contain the safety factor φ, diaphragm factor JD, duration factor KD, service factors KS, treatment factors KTp and KTn , and number of shear planes ns.

iv. Data for Entire Shear Wall.

For each shear wall, there is a line for data that are independent of the wall segment or sheathing side, showing wall height and total shear force Vr in each direction on the wall.

v. Panel Buckling Vrs

For each shearwall, there is a table showing the data needed for panel buckling Vrs calculations from O86 11.5.1(c). There is a separate line for each shearwall segment between openings and for the interior and exterior sheathing sides. The data shown are segment length, sheathing thickness, shear force per unit length, unit panel buckling strength vpb, panel buckling factor Kpb, critical panel dimensions a and b, panel axial strengths Ba0 and Ba90, shear through thickness rigidity Bv, and parameters η (eta) and α (alpha).

vi. Nailing Vrs

For each shearwall, there is a table showing the data needed for nailing Vrs calculations from 11.5.1(b). There is a separate line for interior and exterior surface. The data shown are nail diameter, panel thickness, nail penetration length, shear strength Vhd per unit length, unit shear strength vd, fastener spacing factor JS, unblocked factor JUs, nail spacing, factored nail strength Nu, yield modes a,b, d, e, f and g  for unfactored nail strength nu. marking the critical mode with an asterisk (*) and indicating whether it is ductile or non-ductile.

vii. Jhd and Vrs

For each shearwall, there is a table showing the data needed for hold-down factor Jhd and the determination of final shear strength Vrs. For each wall segment, the program shows the Vhd on each surface derived from the critical panel buckling or nailing Vrs; the combined Vhd, then for each force direction it shows the uplift force Pij used for Jhd, hold-down factor, Jhd, and the resulting combined worst-case Vrs on each surface of the wall.

7. Nail Types and Sizes

As the calculation of shear strength Vrs now depends on the exact nail diameter and nail penetration length, and given the prevalence of power-driven nails, the program has greatly expanded the selection of nails available in Shearwalls.  Unless otherwise indicated, these changes apply regardless of whether O86-09 or O86-14 is selected as the design code.

a) Fastener Types

Previously the nail types available for structural sheathing were Common wire nails and Non-standard nails. The program now allows the following choices

 

Common wire nails

Spiral nails

Ring nails

Power-driven nails

 

Power-driven nails correspond to the previous Non-standard nails, with changes to functionality described below.

b) Manually driven Nails

i. Lengths and Diameters

The following table shows the correspondence between diameter and length for each fastener type now available in Shearwalls:

 

Length (in)

Length (mm)

Common wire nails

Spiral nails

Ring nails

 

 

in

mm

in

mm

Nom in

Nom mm

1-3/4

44

  -

 

  -

 

0.109

2.769

2

51

0.113

2.87

0.120

3.048

0.120

3.048

2

51

 -

-

-

-

0.134

3.404

2-1/4

57

0.113

2.87

 -

 -

 -

 -

2-1/2

64

0.131

3.33

0.120

3.061

0.134

3.404

3

76

0,148

3.76

0.135

3.429

0.148

3.76

3-1/4

83

0,148

3.76

0.135

3.429

 -

 

 

ii. Dependence on Sheathing Size

For CSA O86-14 design, the program no longer limits the fasteners used based on sheathing size. All nail sizes are allowed for all sheathing thicknesses. For CSA O86-14, only nails that meet the min. penetration in Table 9.5.1A are allowed.

iii. Ring Nail Design Diameter

For ring nails, the value shown for diameter is the size of the wire the nails are made from.  The nominal values are shown in the user interface, but for design, the program subtracts 2 mm = .0075” to arrive at the root diameter to be used for the design equations.

iv. 2” Ring Nail Diameters

In previous versions of the program there is a one-to-one correspondence between nail length and diameter. Now there are now two diameters for 2” ring nails. In this case, if you select ring nails, the program selects by default the first of the diameters, 3.048mm, which you can then change. This diameter is be used for design for unknown nail length when the cycle reaches 2”.

c) Power-driven Nails

i. Lengths and Diameters

The following table shows the correspondence between diameter and length for power-driven nails available in Shearwalls:

 

Length

Diameter

in

mm

in

mm

1-7/8

44

0.131

3.33

2

51

0.113

2.87

2

51

0.131

3.33

2

51

0.120

3.048

2-1/8

54

0.48

3.76

2-1/4

57

0.92

2.33

2-1/4

57

0.99

2.50

2-1/4

57

0.105

2.68

2-1/4

57

0.113

2.87

2-3/8

60

0.113

2.87

2-1/2

64

0.120

3.048

2-1/2

64

0.131

3.33

2-5/8

67

0.148

3.76

2-3/4

70

0.148

3.76

3

76

0.120

3.048

3

76

0.131

3.33

3

76

0,148

3.76

3-1/4

83

0.148

3.76

 

Previously the lengths and diameters available for non-standard nails were the same as those for common wire nails, the difference being that you could enter your own value for non-standard nails.

ii. Unknown Nail Sizes

The program now allows you to specify unknown length for power-driven nails, and the program cycles through the possible lengths to achieve design.

If a known nail length is selected, the program lists the diameters for that known nail length only and select the first by default, as the program does not cycle through nail diameters.

If unknown is entered as the nail length, then all possible nail diameters are listed. If you select one of these nail diameters the program will continue to show unknown for nail length, and when the design loop runs, it will only design for nails that have that diameter.

If the diameter is unknown and you in a nail length, the program selects the diameter corresponding to the closest nail in the list to the nail length that was typed in.

iii. Minimum Nail Length

As per NBC Table 9.23.3.5.A, you cannot enter a nail length less than 1.75” – the program will revert to the previous value and issue an explanatory message. Previously there was no lower limit on nail length in Shearwalls.  

If a nail is entered between 1.75” and 2” in length, a message appears saying that the nail should be ring-threaded, as per Table 9.23.3.5.A.

iv. Maximum Nail Length

As per the intent of O86 14 (see J: 8.d) below), you cannot enter a nail diameter greater than 3.76 mm – the program reverts to the previous value and issues an explanatory message.  Although before O86-14 there was no upper limit, this limit is imposed regardless of whether O86-09 or CSA O86-14 is selected in the Design Settings. 

v. Design Routine

When the length and diameter are left as “Unknown”, if when cycling through lengths the program arrives at one that has more than one diameter, it chooses the one corresponding to the common wire nail of that length.

vi. Output

Previously, in the Sheathing Materials table, the size of a non-standard nail was rounded off and converted to the closest fractional size, one which is often the same as a standard nail. Now, power driven nails are output in decimal format to distinguish them from standard nails that are in fractional format.

d) Limiting Nail Diameters

The program is was using nail diameters listed in the CSA O86, from the CSA B111 standard, however it has been determined that these diameters do not correspond to the wire gauges currently used to manufacture nails, which are from the ASTM F1667 standard.  Several limitations are based on the nail diameters, such as O86-14 11.4.5.5 that limits nail diameters when anchorages are used to 3.25 mm, and 11.3.1.1, which says that shearwalls must use nails 3.66 mm or less.

We have changed those limitations 3.33 mm and 3.76 mm, respectively, to correspond to the nail diameters we use in the program for nails of the corresponding lengths.

The messages that appear when these limitations are imposed have been modified to explain this decision.  In addition, if a nail between 3.66 and 3.76 is used in design, or a nail between 3.25 and 3.33 when Jhd < 1, a new note appears below the sheathing materials table saying that the nail conforms to the intent of 11.3.1.1 or 11.4.5.5.  

8. Gypsum Underlay

The program now includes the ability to gypsum underlay because it affects nail penetration and therefore shear strength for O86-14. This feature is also available if O86-09 is selected, and in this case affects whether a nail length achieves minimum penetration for shear resistances in Table 9.5.1

a) Input

Choices of no gypsum underlay, ½”, and 5/8” underlay have been included in the Sheathing data group of the Wall Input form.  The default is None.

b) Design

For O86-14, the penetration depth used to determine the nail strength described in J: 7.c)iv.4 above is reduced by the thickness of the underlay.

For O86-09 the set of nail lengths listed in the input control and used to cycle through for unknown design does not include nails that do not meet min. penetration depths in table 9.5.1A.

c) Output

A column “GU” has been added to the Sheathing Materials by Wall Group table showing the gypsum underlay thickness, with an explanatory legend entry.

9. Nail Slip for Deflection en

The following changes apply to the calculation of nail slip deflection en, which is one of the components of shear wall deflection:

a) Wood Structural Panels

For CSA O86-14, instead of the table from O86-09 A.9.7 the program implements the equation from O86 09 A11.7., which depends on the same inputs – spacing s, diameter d, and shear force v.

For green fabrication conditions, the program multiplies the values from the equation by 2.0.

Note that there is no longer an upper limit on the load for which en values are tabulated, so that the program no longer issues warnings in the Design Results that the load per fastener is too high, and has removed this from the list of things that the Design Summary page does not handle.

b) Gypsum Wallboard

Previously, the program used a constant deflection of 0.03 inches = .0762 mm. The O86- 14 design code says to use 0.76 mm. This slight adjustment has been made. 

Refer to M: 1 below for changes to restrict the use of GWB to dry service and fabrication conditions.

10. Restricting Materials based on Anchorage Selection

The Design Setting Materials Restrictions for Anchorages has been removed from the program, and user interface no longer contains a restricted set of sheathing thicknesses, nail sizes, or nail spacings based on these settings. Given the new shear wall design equations based on nail size and penetration, it is no longer practical to predict ahead of time what materials cannot be included due to the restrictions in 11.4.5.5 regarding the applicability of Jhd < 1.

The program now behaves as if the setting Over-ride hold down selection to achieve design is always selected. In other words, unless you have specified in the Wall Input view that hold-downs are to be used, the program applies hold-downs only where needed to achieve design, otherwise anchorages are used.

Upon reading project files from previous versions, the program will reset the materials restrictions setting to Over-ride hold down selection to achieve design, so that the behaviour of these projects will change.

11. Gypsum Wallboard (GWB) Design

The following changes apply to when gypsum wallboard is used as a shear-resisting material.

a)  Maximum Percentage GWB for Wind

O86-09 Table 9.5.4 for Maximum Percentage Gypsum Wallboard, which previously applied to both wind and seismic design, has been moved to O86-14 11.8.8, a section that is for seismic design only. Accordingly, for wind design the program no longer calculates the gypsum wallboard percentages, the Maximum Percentage Gypsum table is no longer output, and design failure warning messages no longer shown on the screen or in the results output.

This change has been implemented regardless of whether O86-09 or O86-14 is chosen as the design code, as WoodWorks has been informed that it was always the intention that these restrictions applied to seismic loading.

b) GWB Percentages for Rd and Ro =1

A sentence has been added to O86 11.8.8 saying that the Rd and Ro values can each be reduced to 1.0 if the GWB percentages are exceeded. Previously it was an absolute requirement that the GWB percentages not be exceeded. The program therefore no longer displays a Maximum Percentage Gypsum Wallboard table for seismic design if Rd and Ro are both less than or equal to 1.0, outputting an explanatory note instead.

The operation of various screen warning messages and output warning notes that appear when gypsum wallboard limitations have been modified to take the possibility that Rd and Ro both equal 1.0 into account.

c) Storey Drift Limitation for Gypsum Wallboard

A sentence has been added to O86 11.8.8 saying that gypsum wallboard does not contribute to seismic resistance if the interstorey drift ratio is greater than 1.0%, that is, if the drift of one storey relative to another is greater than 1% of storey height, as opposed to the 1%, 2% or 2.5% allowed now by NBC 4.1.8.13.(3) according to building type.

To implement this, the program now records the largest drift of any shearline with GWB that is active for design on each storey and force direction. In the storey drift table, if some shearlines on the level/direction indicated have GWB and some do not, for that level/direction the worst case GWB deflection and shearline with the maximum deflection are both output, unless they are the same shearline.

If a shearline fails because it has active GWB and its storey drift is between 1% allowed for gypsum and the percentage allowed for the building type as per NBC 4.1.8.13 (3), then double asterisks (**) appear at the design ratio and a modified failure warning appears.

d) GWB Shear-through-thickness for Deflection Bv

For gypsum wallboard, the shear-through-thickness value Bv has changed from 7005 N/mm to 7000 N/mm, as per CSA O86 11.7.1.2. Previously O86 did not provide guidance for this value, and Shearwalls was using 40,000 lbs/in converted to N/mm. The program still displays 40,000 lbs when imperial units are chosen.

This change is in effect regardless of whether O86-09 or O86-14 is chosen as the design code.

12. Service Condition Factor KSF

The fabrication moisture content for which any value greater is considered to be green in O86-14 Table 12.2.1.5 and a non-unity factor is applied, has changed from 15% to 19%. This change has been implemented to the service condition factor applied to nail withdrawal and shear strength calculations. In addition, the default for new files has changed from 15% to 19%.

Refer also to K: 14 below Moisture Conditions Description in Design Settings Input and Output

B:  Other Engineering Design

1. Unit Nail Resistance Nu for Anchorage Deflections

The following problems in determining the value of Nu used in O86-09 9.7.1.1 for the anchorage component of shear wall deflection, when calculating embedment strength f1 of the sheathing in 10.9.4.2, were corrected:

a) Yield Mode Equations for Anchorage Deflections (Bug 2986)

The program erroneously used the value of the dead load component of the hold-down force in N in place of the nail diameter in mm.

If there are no dead loads at the hold-down location, or dead loads less than or just a little more than 10 N, then the program would calculate the wrong f1 value in the yield mode equations, and non-conservatively so. If there are dead loads significantly greater than 10N (which is very small), then the program would not include the yield mode terms that include f1 when determining the hold-down values. That is, it would use yield mode b only. This will also be a non-conservative error in most cases.

This bug interacted with bug 2991, below, which results in very large anchorage deflections, so that if there are significant dead loads, this bug counteracted the other bug so that together they create unreliable results.

b) Sheathing Specific Gravity for Anchorage Deflections (Bug 2991)

In determining the value of Nu used in O86-09 9.7.1.1 for the anchorage component of shear wall deflection, when calculating embedment strength f1 of the sheathing in 10.9.4.2, the program used sheathing specific gravity values 1/10 of those listed in O86-09 10.9.4.2. They were G = 0.049 for DFP and 0.042 for CSP and OSB, as opposed to 0.49 and 0.42,  respectively. This caused anchorage deflections to be roughly order of magnitude larger than they should be, however this varied widely from shear wall to shear wall. This error could also cause forces to the individual shearlines to be distributed to the segments incorrectly in an unpredictable way.

This bug interacted with bug 2986, above, which caused the f1 value never to govern if there were significant dead loads, so this bug would have no additional effect in that case. If there are dead loads, this bug counteracted the other bug so that together they create unreliable results.

2. Shear Wall Capacity Hold-down Method in the Calculation of Deflections (Bug 2999)

When shear wall capacity is used as the design force for hold-down design, either via the design settings or because it is required due to seismic irregularities, this value was also used to determine the hold-down component of shear wall deflection. As this is not the intent of the use of shear wall capacity to ensure sufficient hold-down strength, the calculation for deflection now always uses applied force to determine hold-down displacement, regardless of the design setting for hold-down forces or the existence of irregularities.

a) Determination of Irregularities after Redesign (Bug 2998)

After determining the structural irregularities, the program if necessary changes the hold-down method to capacity and then recalculates deflections, redistributes loads based on these deflections, and sometimes redesigns the structure. However, because hold-down deflections were based on shear wall capacity, reconfigured building may not have the same irregularities as before, but the program does not recalculate them. It was therefore possible that irregularities shown in the output and those that actually apply to the structure did not match.

In particular, the deflections used to determine Bx, the torsional sensitivity, were not the same as the ones that are shown in the output for the redesigned building. It could even happen that the program determined the building was torsionally irregular, changed the hold-down setting, and the redesigned building was no longer torsionally irregular.

This situation can no longer occur, because the change in hold-down method to being capacity-based no longer affects deflections.

3. Non-standard Nail Diameters (Bug 2664)

When a non-standard nail diameter was entered, the program ignored it and used the diameter of a standard nail with the input length.  The standard diameter appeared in the Sheathing Materials table, and the shear capacity reduction factor in A9.5.1.2 was not applied. When deselecting the wall then reselecting it, the standard diameter would reappear.

Non standard nails are now called “power-driven” nails, and function as intended.  The program uses the nail length and nail diameter in the new design equations for shear wall shear resistance based on nail strength from O86-14 11.5.1, and the nail diameter in the design procedure from A9.5.1.2 when O86-09 is selected.  

4. Wind Load Storey Drift Table (Bug 3032)

The program now outputs a Storey Drift for wind loads, showing the maximum deflection of any shearline for every storey and direction, and compares it with the limit in NBC 4.1.3.5 3) of 1/500 of storey height. Note that sentence 4) of this 4.1.3.5 exempts industrial buildings and sheds, however Shearwalls does not take this into account and outputs a storey drift table for all structures. Please disregard the table for industrial buildings and sheds.

A failure for wind storey drift is output in the Design Summary as one of the new secondary seismic design checks described in Item 6., below, Special Seismic Checks in Design Summary.

5. Standard Walls and Design Groups

The following problems related to standard walls, design groups, and the interaction between them, were corrected:

a) Saving of Standard Walls Modified in Wall Input View (Bug 3015)

Upon exiting the program, it saved the changes made to Standard Walls that occur when changes are made to walls in the structure while "Design in Group" is checked.  Therefore, changes you might inadvertently make while modifying walls could affect the standard walls used for future sessions.

Now, the program asks you whether you want to save the standard walls when exiting standard wall mode and when exiting the program. When exiting the program this prompt only appears if a wall has ever been modified in this way.

Previously, the program saved standard the standard wall file that is used for future sessions when saving a new standard wall, deleting a standard wall, leaving standard wall mode, or selecting a new standard wall in the drop-down list in standard wall mode.  It now only saves the standard walls when leaving standard wall mode and when exiting the program.

b) Creation of Standard Wall from Wall in Structure (Bug 3025)

The Design in Group feature proved to be difficult to implement for a wall that had been created input of walls in the structure rather than via Standard Wall input, because there is no standard wall associated with the wall and design groups are accomplished through standard walls.  

For this reason, the program now allows you to create standard walls from regular walls as follows: 

When clicking "Edit Standard Walls" while there is a wall selected which does not match any standard wall, the program now asks you if you wish to create a standard wall based on the selected wall. If you create a standard wall in this way, the Design as Group setting is checked for the standard wall and the Design in Group checked for the selected wall.

This feature enhances the program usability in general, similar to the creation of a new font style in a word processor using the font attributes of the selected text. 

c) Persistence of "Design as Group" Checkbox in Standard Wall Mode (Bug 3022)

When you unchecked the Design as Group checkbox in Standard Wall mode, the change is not retained when selecting another standard wall or exiting the box, making it impossible to specify that standard walls are not designed as a group.

d) Standard Wall Name Persistence when not Designing as Group (Bug 3026)

Sometimes, after selecting a standard wall that is not designed as a group, the standard wall name goes blank in the input field rather than showing the selected standard wall. This has been corrected. 

This happened most often when multiple walls were selected and has been corrected.

e) Design as Group for Multiple Identical Wall Groups (Bug 3026)

When design as group is activated for a standard wall that has the same materials as another standard wall group, the program sometimes assigned individual shear walls to the wrong design group, that is, to a design group for a standard wall group other than the one designated for that wall.

6. Nail Deformation en for Deflection from O86 Table A.9.7

The following problems relating the nail deformation en value from CSA O86-09 Table A.9.7 have been corrected for when CSA O96-09 is selected as the design code. They do not affect program behavior when O86-14 is selected.

a) en for Larger Nail Sizes (Bug 2583)

When a nail size other than the smallest one in the table was chosen, the program used an en from the next smallest standard nail size rather than the nail size selected. This resulted in a greater than expected nail slippage component of deflection. This problem did not occur when a non-standard nail intermediate between two standard sizes was entered; in that case the program correctly selected the lower value.

b) Warning Message for Nails Less then Minimum Diameter (Bug 3079)

If you entered a nail diameter less than 2.84, the lowest value in the table, the program issued a warning message under the Deflection table in the Design Results about loads per nail being over the highest allowable, even if the loads were within range. The en value used was for the largest diameter and highest loading.

The program now disallows selection of nails less than 2.84 mm in diameter if deflection analysis is turned on.

c) en when Loads Greater than Maximum (Bug 3079)

If the load per nail was greater than the highest allowable, the program used highest nail slip value for the 3.66 mm diameter nails, or 0.98 mm, not the deflection value for the nail that was selected. As this is the largest diameter, which has the lowest deflection, it creates non-conservative deflections for all other diameters.

Note that a warning message is still issued in this circumstance because even though the en is now for the correct nail size. it corresponds to loading less than what is actually on the nail. 

7. Special Seismic Checks in Design Summary (Change 220)

In the Design Summary, the program previously reported a list of items that were not included among the checks being summarized, even though the program made those checks in the course of seismic design. Now, these checks are reported as having passed or failed. These checks are:

-        Percentage gypsum wallboard from O86-14 11.8.8 or O86-09 9.5.4

-        Storey drift from NBC 4.1.8.13(3) and O86-14 11.8.8.

-        Seismic Irregularities from NBC 4.1.8.6

-        Over-capacity ratio from O86-14 11.8.3.2 or O86-09 9.8.3.2 

8. Message Box for Gypsum Wallboard Rd Factor

The following problems relate to the message box that appears when the Force Modification factor Rd selected in the Site dialog is not the one appropriate for the materials used, and have been corrected:

a) Gypsum Walls with Rd Greater than 2 (Bug 2968)

The message box during load generation indicating that an Rd factor of more than 2 should not be used when there are gypsum materials in the structure was not appearing when all the walls with gypsum sheathing had both sides sheathed with gypsum. This has been corrected.

b) Gypsum Walls with Rd = 2 and Ignore Gypsum Unchecked (Bug 2674)

While generating loads for shear walls with gypsum on one side and the Rd set to 2, the value appropriate to gypsum walls, with the setting for ignoring gypsum unchecked, the program nonetheless issued a message that this setting was active and the offering to either change the Rd value or uncheck the setting.

If you selected "No" to uncheck the setting, the setting remained unchecked program continued to generate loads with the correct Rd value.

9. Percent Resisted by Gypsum Table

The following problems related to the Percentage Storey Shear Resisted by Gypsum Wallboard table used to implement O86-09 Table 9.5.4 have been corrected.

a) Percent Resisted by Gypsum Table when no Gypsum Present (Bug 3013)

The table no longer appears if there is no gypsum wallboard on the structure.

b) Direction Percent Resisted by Gypsum Calculation (Bug 3014)

When calculating gypsum and wood capacity only one force direction case was considered: the east-to-west or north-to-south case. Therefore, when the table indicated was displaying results from the south or west direction, it was actually displaying the results for the opposite direction. The program now calculates the percentage shear force in each direction independently.

10. "Improper Argument" error for OSB Sheathing (Bug 3012)

Upon designing walls with OSB sheathing with unknown panel marking, sheathing thickness and non-standard nails selected, an "Improper Argument" error message appeared and an incorrect Jn factor was calculated, invalidating design.

This has been corrected.

11. Elevation View Failure Message for Passing Walls (Bug 3007)

Elevation view was sometimes showing the FAILED design message for interior walls even though the walls passed design. This could happen when you had selected to allow anchorages rather than hold-downs on the wall, and the design setting was set to allow the program to "over-ride" the use of anchorages if necessary and impose hold-downs. This has been corrected.

12. Both Direction Output in Storey Drift Table (Bug 3018)

In the storey drift table, the program used to output Both to indicate, for example that the results apply to both E->W and W->E. However, this table also includes results from the other orientation, in this case N->S and S->N, so it was unclear what Both referred to. The program now says e.g. E<->W when indicating the results apply to both directions rather than Both.

13. Moisture Conditions Label (Change 217)

The notation (%) has been added to the data group label for the Moisture Conditions settings, to indicate that the numbers shown are percentage moisture content.

14. Moisture Conditions Description in Input and Output (Change 218)

Adjacent to the input of Moisture Content in the Design Settings, the program now indicates whether the value is dry, wet, or green (O86-14), or dry, wet, seasoned, or unseasoned (O86-09).  This is now also indicated in the Design Results echo of the Design Settings.

15. Extra Null Lines in C&C Design Table (Bug 3035)

For some cases in which not all of the wall design groups are standard walls, and when only one of rigid or flexible design is performed, the program prints out an extra line for each C&C result in the output table with 0 load and 0 capacity, additional one wall design groups not related to any actual walls are created with, with 0 load and 0 capacity. These problems have been corrected.

16. Plan View Legend Wording for Failed Walls (Change 177)

The line in the plan view legend explaining the red color for failed walls now indicates that it is a “Capacity” failure, to clarify that other types of failures now reported in the Design Summary are not highlighted.

C:  Loads and Forces

1. Duplicate and Missing Low Rise Wind Loads (Bug 3002)

The program would sometime take portions of low-rise wind loads generated for one corner load case and assign them to another corner load case, creating duplicate loads for one case and gaps in the other case. This was most likely to occur if the structure is heavily indented, and has been corrected.

2. Centre of Mass and Center of Rigidity in Plan View (Feature 218)

The program now shows the location of the center of loads and the center of rigidity of the structure, for both wind and seismic loading. These appear in Load Generation action when Rigid forces are chosen for display. Two small dots with the symbols CL and CR appear.

You can turn on and off the display of these points using the Show menu.

The distance between these points in each direction is the moment arm used for torsional analysis for rigid diaphragm distribution.

3. C&C Wind Loads in Both Directions (Change 176)

When adding a new C&C load, it is now possible to select "Both ways" for wind direction, as the program now distinguishes between suction C&C loads for both nail withdrawal and sheathing strength, and bearing wind loads which impact sheathing strength only. .

4. Crash Upon Input of C&C Load (Bug 176)

Starting with version 9, after entering a C&C wind load in Load Input form, and if there are no generated loads, the program would crash upon exit from the dialog.  This has been corrected.

5. Update of Add Load Dialog Input (Bug 3005)

The following corrections have been made to the Add a New Load dialogue box:

a) Wind C&C Loads

When Wind C&C is selected,

-          The Apply to... input was limited to Building face but the list was filled with wall lines. The Apply to input now shows Wall lines

-         The magnitude labels From and To changed to Interior and End but failed to consistently update back to From and To when a different type was selected.

b) Apply to Selected Walls

When Apply to… Selected Walls was selected, the From and To location did not update properly so that the load would not be applied to just the extent of the selected wall.

c) Dead Loads on Building Face

You can no longer apply dead load and building mass loads to an entire building face. These loads are more appropriate to a wall line.

d) Element for Wall Line Loads

 For wind shear and seismic loads, the Element was always shown to be Face even when applied to a wall line. It now shows the wall line it was added to.

e) Width of Load List (Bug 3077).

The list of input loads has been widened to show the Profile column without scrolling.

6. Missing Elevation View Forces in for No Deflection Analysis (Bug 3003)

When the Design Setting was set to exclude deflection analysis, the shear flow arrows for diaphragm shear and base shear and the segment shear force arrows did not show up in elevation view. This has been corrected.

7. Missing Snow Load Note in Load Generation Dialog (Bug 2988)

Under Seismic Loads in the Generate Loads dialog, the note giving the percentage of snow load used was missing. It has been restored to the program.

8. Nonsensical Torsional Forces in Log file for Low Rise Wind Design (Bug 3006)

Generating low-rise wind loads on a structure with a flat roof would sometimes show nonsensical output in the log file for the rigid distribution torsional forces for low-rise case B wind loads.  As these cases have a net zero wind load in the direction with nonsensical output, this did not affect design. It has been corrected.

9. Multi-block Low Rise Height to Width Setting (Change 183)

The Design Setting which indicated whether the structure height-to-width ratios are based on a single block or multiple blocks has been removed from the program, as it had no effect.  This setting had been put in the program as part of ongoing development to implement multi-block low rise procedures; however this feature has not yet been released.

10. Site Information Output

The following changes have been made to the Design Results output pertaining to wind and seismic load generation site information:

a) Wind and Seismic Load Generation Procedure (Change 196)

For design method, the USA ASCE 7 seismic load generation procedure was showing, and for wind, the "N" was missing from NBC. These problems have been corrected and the program now shows the full NBC procedure for both.

For wind design, the program was showing the choice of low rise (Fig. I-7/8) or all-heights (FigI-15), but that information is also in the Design Settings output. Instead, in the Site Information the program now shows Static Procedure from NBC 4.1.7.

b) Cgi Notation (Change 198)

CGI has changed to Cgi. 

11. Load Generation Details Results in Log File

The following changes have been made to the log file showing detailed wind and seismic load generation information:

a) Log File for New Project (Change 184)

Pressing log file button for a new project displayed the results from the last unsaved session. The log file button is now enabled until loads have been generated.

b) File Header (Changes 187, 179)

The following changes have been made to the log file header block:

-        the date and time now appear at the top of the file instead of each title block of the wind, seismic and torsional analysis information. The unnecessary word “Time:” has been removed.

-        the header now includes the version number of the software,

-        the program name, version, filename and date are separated by a blank line from the design code information below. 

-        The header was not appearing if was seismic only loading and thus no wind load generation section. This has been corrected

c) Page Numbers (Change 188)

Since the log file was placed in a viewer within the Shearwalls program with version 9.0, page numbers no longer appeared. This has been corrected.

d) Table Alignment in Viewer (Change 214)

The log file was designed to be shown in Windows Notepad, which has a tab width of 8. The new internal text viewer uses a tab width of 6, so some output tables were misaligned with their headers. Tab stops have now been replaced by spaces to avoid this problem.

e) References to NBC (Change 191)

The references to NBC design code clauses now follow the format NBC uses when referring internally to other sections of the publication, e.g. 4.1.7.1.(6)(c)  . Previously there had been inconsistent formatting.

f) Fractional Exponents in Equations (Change 192)

The formatting of fractional exponents in equations has been changed from fractional to decimal to conform with NBC formatting, e.g. (h/10)^1/5 is changed to (h/10)^0.2

g) Site Info and Legend Format (Change 189)

Information in the log file site information and definitions legends that was previously separated by semi-colons has been placed on a separate line for readability.

h) Formatting of Subsections (Change 201)

Where a subsection of the report contains more than one simple table, a blank line has been placed after the heading to the subsection to indicate that all the information below it pertains to that heading.

i) Wind Load Legend Nomenclature and Formatting (Change 190)

The following changes have been made to the legend to the wind load section of the log file 

-        Cg – Internal is changed to Cgi - Internal

-        P for Pressure has changed to p; also changed in the equation below and column headers

-        Commentary 31 changed to Commentary I-31

-        LC = Case A or B changed to  LC = Load Case A or B in Figure I-7

-        Added line Dir = direction (WW = windward, LW = Leeward)

j) References to Ce Equations (Change 193)

The reference to the equations for exposure factor Ce from the NBC has been made more exact, changing   4.1.7.1 5) to 4.1.7.1.(5)(a). and 4.1.7.1.(5)(b). for open terrain and rough terrain, respectively.

k) Main Wind Force vs. C&C Loads (Change 194)

Main Wind Force and C&C loads have been split into separate tables for readability. Previously there were two sets of headers for the tables and you had to correlate information for the type of load being read with the correct header line.

l) Cei and Cgi Format for C&C Loads (Change 195)

The internal exposure and gust co-efficients Cei and Cgi are now output to 2 decimal places instead of 1, similar to Ce and Ci.

m) Seismic Method (Change 199)

The design code clause reference has been added to the seismic design method shown in the header to the section on seismic load generation, and the redundant output of 2 lines repeating the NBC design code under the seismic site information have been removed.

n) Seismic Site Information

The following changes have been made to the echo of the user-input Site Information:

i. Seismic Site Information and Legend Titles and Location (Change 200)

The output of Site Information for seismic load generation has been made consistent with wind by removing the words "User Input" and placing it first in the sequence of information reported.

ii. Importance Category (Change 202)

Risk in the seismic Site information section has been renamed Importance category and moved to be adjacent to the Importance Factor Ie.

iii. Fv Formatting (Change 203)

The extra spaces before the output of Fv in the seismic Site Information have been removed.

iv. Ta and Rd,Ro in  Seismic Site Information (Change 205)
The seismic site information now indicates whether the Ta used is from the equation listed below or from the user input over-ride, and indicates that the value is shown in the Base Shear table. It also indicates that Rd and Ro are in the Base Shear table, in order to make it clear that these values are input and not calculated.

o) Seismic Legend (Changes 210-211)

The following changes have been made to the Symbols section for seismic load generation

-        This section has been renamed Legend, consistent with Wind output.

-        The definition of Vx has been removed, as it does not apply to NBC design.

-        For Fx, design seismic force… has changed to "lateral force... so that it matches NBC usage.

-        wi and wx are changed to Wx and Wi for consistency with NBC notation

p) Seismic Equations (Change 204)

The following changes have been made to the Equations section for seismic load generation:

-        The definitions have been removed from in front of V, Ta, Ft and Vx since these are already supplied in the Legend section.

-        Segment Lateral Force: Vp and Top Storey Shear Force: Vn have been removed, as they are from old design code editions and are now obsolete.

-        The words hn in m have been added to the expression for Ta to indicate for imperial output that that expression is valid only when Ta is in metric units. 

-        wi and wx are changed to Wx and Wi for consistency with NBC notation.

q) Calculation of Base Shear Table (Change 212)

The following changes have been made to the Calculation of Design Base Shear section:

-        The value of hn, the height of the top level, is now shown below the Calculation of Design Base Shear

-        The notation T has been changed to Ta, for consistency with NBC and the rest of the report

-        The notation S has been changed to S(T)

r) Distribution of Base Shear to Stories (Changes 206-209, 212)

The Distribution of Base Shear to Stories table often appeared in a puzzling, ragged format because an earlier format with the stories arrayed horizontally was shown along with the current format with the rows arranged vertically. This has been corrected, and the following changes have also been made:

-        When you chose in the Format Settings to show distances in feet and inches, the table would show the storey height that way rather than in decimal format, which is used for all output reports.

-        The final column is now headed by Fx instead of Vx, in keeping with NBC terminology

-        The name of the table has been changed to Distribution of Base Shear to Levels, to avoid the complication of differing spelling of the word storey for USA and Canada.

D:  Materials

1. OSB and GWB in Wet Service Conditions (Bug 3000)

Oriented strand board (OSB) and gypsum wallboard (GWB) are no longer allowed for wet service conditions, as these materials are not permitted for wet service conditions according to O86-14 9.4.2 and Table 11.5.4 Note 2, respectively. When you try to add one of these materials to a structure for which wet service conditions is set, the program disallows the entry. If such materials exist in the structure, the program disallows entry of in-service moisture content greater than 15% (O86-14) or 19% (O86-09). An on-screen explanatory warning is issued when the program rejects a change.

The program also changes the in-service moisture content from existing files, when opened, if GWB or OSB is used anywhere in the structure.

Because CSA O86 A.11.7 for gypsum wallboard nail slip deflection en is for dry fabrication conditions only, changes resulting in these GWB along with green fabrication conditions and deflection-based force distribution cause the setting for ignoring non-wood-panel materials for design to be set.  If the setting for deflection-based force distribution is not set, the program allows green fabrication conditions but issues an on-screen message and a warning under both the Deflection table and the Storey Drift table in the Design Results.  

2. Plywood Sheathing Plies (Bug 2994)

The following problems relating to the selection of plywood sheathing plies in the Wall Input view have been corrected.\:

a) Available Plies

Not all the selections for plywood sheathing plies from tables 7.3A and 7.3B were available for each thickness. In particular, 3-ply 12.5 and 6- ply 15.5 were not included. These had been added for CSA O86-09 but not incorporated in the software until now.

b) Default Plies

When the thickness is changed, the program now defaults to the no. of plies for the most commonly available material as shown by the asterisk in Table 7.3A and 7.3b

3. Custom Plywood Thickness (Bug 2994)

The following problems occurred when custom plywood thicknesses were entered, rather than using a standard value from the list. This is not recommended and rarely done because such thicknesses are not available commercially. They have been corrected, nonetheless.

a)    Ply Selection

After typing in a custom thickness for plywood, the selection of plies remained the same as for the previously entered standard thickness. The program now updates to show plies that are available for the closest standard thickness that is smaller than the entered custom thickness.

b) Zero Bv

When determining the shear-through-rigidity thickness, Bv, for the shear deflection calculation in O86-09 9.7.1.1, the program would sometimes use a value of zero for Bv because the number of plies was invalid for the next smallest thickness. This caused the vHs/Bv term to be undefined in the deflection equation. 

c) Bv for Sizes Greater Than 18.5mm

There exist values in Table 7.3A and 7.3B for shear-through-thickness rigidity Bv for panels thicker than 18.5mm, but if a custom thickness is entered that is larger than 18.5 mm, the program still used Bv values associated with 18.5mm that were as much as 60% smaller than in reality. Note that the use of panels greater than 18.5 mm is exceedingly rare.

d) Upper Limit on Sheathing Thickness

You could type in sheathing values greater than 31.5, the largest for which values exist in Tables 7.3A and B. Since such plywood does not exist in practice, the program now limits input to 31.5 mm.

4. Nail Penetration Imperial Unit Format (Change 180)

The nail penetration shown in the Sheathing Materials table is now formatted as a decimal instead of as a fraction when in imperial units.

5. Nail Diameter Format (Change 219)

For non-standard (now power-driven) nail input in Wall Input view and output in the Sheathing Materials table, the program now shows the millimeter value with 2 digits precision, without truncating trailing zeroes, e.g "3.00" instead of "3'.

6. MSR Grade Design Note (Change 215)

The Note 7 giving the MSR grade under the Sheathing Materials table in the Design Results output has been eliminated, and instead, under Species if the framing material type is MSR or MEL, the word “MSR” or “MEL” appears in front of the species name. The eliminated note had the following problems:

-        It was under the Sheathing Materials table but should have been under the Framing Materials table. 

-        It output the E grade for MSR, but since deflection design was implemented, that value was added to the Framing materials table.

-        It said “MSR” even if it is MEL. There was no way of knowing it was MEL.

-        It repeated itself unnecessarily.

-        It should have said “for framing members”, not “as framing members”.

7. OSB Panel Marking Design Note (Change 216)

The Note 8 giving the OSB panel marking under the Sheathing Materials table in the Design Results output repeated itself for every wall with the marking, which defeated the purpose of creating the note. This has been corrected and it now outputs out each marking M1, M2, or M3 just once. 

E:  Program Operation

1. Extend Upwards Operation (Bug 3073)

In extending upwards in stages, the program created an extra level on the level above the one you selected to extend to and uses the original block outline to create that level instead of the modified footprint. You could then only extend from that level upwards.  For example, extending to level 2 on a 4-storey structure, the program copied the modified footprint to level 2 and added the original footprint to level 3, and placed you on level 3.  If you extend to a level below the top, the extra level was placed on the topmost level and the process was complete.

This extra level is no longer added when extending levels in stages, for example if you extend to level 2, the program merely copies the modified ground floor level to level 2 and places you there to proceed.

2. Settings Dialog for Medium and Large Display Size (Bug 3068)

It was sometimes not possible to view all the Settings input tabs when medium or large Display Size was selected in Windows. In particular, it could happen that you were unable to click the buttons at the bottom that close the boxes.

These boxes have now been reorganized in a shape similar to that of a typical computer screen, so that the entire box fits in the view regardless of the display option selected.

3. “Getting Started” Steps Display (Change 181)

The list of steps helping you to get started using the Shearwalls program has been placed in a scrollable view and formatted with bold titles for each step. The number of steps had become too large to fit on the screen without a scroll bar.

4. Main Toolbar (Change 197)

The following changes have been made to the main toolbar:

-       Results View has been renamed Design Results.

-       Design Results has now been grouped with icons for detailed output for load generation and torsional analysis (formerly Log file) and the new Detailed Shearwall Design output

-       Design Results has now shows rectangles representing tabular data to differentiate it from the detailed text results.

-       Form View has been changed to Input Form

5. WoodWorks Sales and Technical Support Contact Information (DO Change 6)

In both the Key code Registration box and the Help About box, we have

-        removed word Support from "Sales Support”.

-        asked users to provide company name rather than address.

-        removed fax as a means of communication.

-        emphasized email instead of phone as a means of contact.

-        changed the email address to be a link that opens an email message.

6. Parentheses in the Help About box (DO Change 7)

Where parentheses were used in the Help About, the closing parenthesis appeared inverted at the start of the line instead of where it should have been. These occurred around things like the date of publication and the relevant parts of design code publications, and have been replaced with a dash as a means of delineating them.

7. Apply Button in Settings Dialog (Change 185)

The “Apply” button has been removed from the Settings dialog because it had no effect.

8. Update of Roof Overhang Input (Change 186)

In the roof input form, the roof overhang values were being set to zero when switching from a flat roof to a sloped roof and back again. They are now restored to their previous values.

9. Image File Wording in Message (Change 182)

In a message saying that the CAD file had not been imported, the words Windows metafile have been changed to image file, as several types of images are now imported.

10. Typo in Out-of-date Design Message Box (Change 178)

The repeated word “design” has been removed from the message box that appears telling you that your structure has changed, and your previous design is out of date.

 

Shearwalls 9.2.1 Hot Fix – March 16, 2015

This version was sent to individual users to address Bug 3002 - Duplicate and Missing Low Rise Wind Loads, which is listed under Version 9.3, the first version distributed to the general public with this fix.

Shearwalls 9.2 – November 19, 2014 - Design Office 9, Service Release 2

1. Upper Level Failures In Hold-down Design Summary (Bug 2948)

The Hold-down Design table of the Design Summary output was reporting walls as having failed hold-down design for multiple building levels when it only failed hold-down design on the lowest level listed. This has been corrected.

2. Duplicate Wall Wind Shear Loads for Additional Roof Blocks (Bug 2946)

After additional blocks are created for roofs only, with no attached walls, the program was creating a duplicate set of wall wind shear loads for walls on the other blocks. For multi-storey buildings this was happening on all levels except the top level.

If the project file was saved and then re-opened and then loads were re-generated the duplicate loads were no longer being created. This has been corrected.

3. Crash on Accept Design for Exterior Non-Shearwalls (Bug 2934)

When there were non-shearwalls on the exterior of the building with C&C loads, Shearwalls would crash when the Accept Design button was pressed. This has been corrected.

4. Crash After Deleting Additional Roof Block (Bug 2947)

After additional blocks are created for roofs only, with no attached walls, and wind loads were generated on these blocks, then one of these blocks is deleted, the program would sometimes crash the next time you tried to save the file, re-generate loads, or run design. This has been corrected.

5. Plan View Freeze for Exterior Non-Shearwalls showing Design Group Numbers (Bug 2935)

If you elected to show the design group numbers for each wall in Plan View via the Show menu, the drawing would not be updated if there were non-shearwalls on the exterior surface of the building with C&C loads. The Plan View drawing would freeze up until you disabled this option. This has been corrected.

6. C&C Design Results for Non-shearwalls on Exterior Walls (Bug 2937)

The Components and Cladding table in the Design Results was not including results for exterior shearlines which had only non-shearwalls on the line. This has been corrected and results now appear for these walls.

7. Materials Output for Non-shearwalls on Exterior Walls (Bug 2936)

The Sheathing Materials and Framing Materials by Wall Group tabled by in the Design Results were not including results for exterior shearlines which had only non-shearwalls on the line. This has been corrected and results now appear for these walls.

8. Wind Suction Title (Change174)

The title in the program output "Wind Suction Design" has been changed to "Out-of-plane Wind Design". This is because the governing condition can be either suction or bearing of wind.

9. Ctrl-C Operation (Bug 2964)

Previously pressing Ctrl-C caused a file close, when the standard operation that users expect is to copy selected text in an edit control, leading to significant frustration. This has been corrected and Ctrl-C now copies text and there is no shortcut for closing a project file. .

 

Shearwalls 9.1 – October 29, 2014 - Design Office 9, Service Release 1b

1. Accept Design for Existing Files (Bug 2903)

For saved project files, the Accept Design button was defaulting to accept flexible wind design, instead of the currently selected load case and distribution method. If there were no wind loads the Accept Design button had no effect. This has been corrected.

2. Inconsistent Design Results on Consecutive Runs for Capacity-based Distribution (Bug 2904)

The program was producing different rigid load distributions and wall designs on consecutive design runs for the Use shearwall capacity to approximate rigidity rigid distribution setting. None of the design runs could be assumed to be correct due to instability in the updating of segment rigidities.  This has been corrected. 

3. Relative Rigidity in Wall Input View after Accept Design (Bug 2909)

After pressing the Accept Design button the relative rigidity in the Wall Input view was showing 1.0 instead of the rigidity from the accepted design wall.

This is just a display issue and the correct rigidity was used in design. It has been corrected.

4. Gypsum Wallboard Shear Rigidity Bv in Design Results (Bug 2911)

When imperial units are used, the shear rigidity Bv value for gypsum wallboard shown in the sheathing information table of the design results was the correct value divided by 12.  This was a display issue only and did not affect design. It has been corrected.

Note that this value comes from the USA SDPWS in the absence of Canadian guidance.

5. Rigidity Shown in Wall Input for Redundant Wind Directions (Bug 2913)

When the Wind directions S->N, E->W and N->S, W->E are selected in the Show menu, the Rigidity shown in Wall Input view was a nonsensical value. This was a display issue only and the correct rigidity was used in the shear wall design. It has been corrected.

6. Non-shearwall C&C Failure for Rigid-only Design (Bug 2919)

If only rigid diaphragm analysis is selected in the Structure Input view, the program shows failure for non-shearwalls in elevation view, even if the walls are strong enough to resist design. In the Components and Cladding table, the program showed a warning that these walls do not have shear resisting materials, even If they did.

This problem disappeared if you chose to do both rigid and flexible design. It has now been corrected.

7. Zero Magnitude Wind Load Generation for Flat Roofs (Bug 2922)

Occasionally when wind loads with zero magnitude were generated on single faces of buildings with flat roofs. This problem occurred only sporadically and has been corrected.

8. Selection of Standard Walls that Differ Only by End Studs (Bug 2923)

When selecting a standard wall to assign to a physical wall, the number of wall studs was not being accounted for, so that if there were two standard walls that were identical except for the number of wall studs it sometimes would cause the program to assign the wrong standard wall to the selected wall. It was also not possible to select one of the standard walls in the Edit standard wall view.

Whether or not it happened depended on the order of the near-identical standard walls in the list of walls. It has been corrected.

9. Redundant Design Groups with Differing Penetration Depths (Bug 2924)

Sometimes extra, unnecessary design wall groups were being created with a nail penetration depth 1mm larger than another wall group, when the walls should actually be in the same wall group and have the same nail penetration depth. This occurred only sporadically and has been corrected.

10. Unknown Values on Interior Wall Surface (Bug 2925)

In wall input view, if you selected "Both sides the same" and specified unknown values, and then deselected Both sides the same, the unknown values were still recorded in the interior sheathing, even though design for unknowns is not done independently for interior sheathing. If these unknown values were not changed, the program would design using the weakest materials in the list, and would show question marks (?) in the Wall Design Groups output table for the interior sheathing.

Now, when you deselect Both sides the same, the program changes any unknown values on the interior surface to the weakest possible. Unless changed, these materials now show up in the Design Group Output.  

11. Crash for Failed Walls with Non-shearwall Shearlines (Bug 2926)

Starting with version 9, the program would sometimes crash after designing a structure in which some wall lines are entirely non-shearwalls, and some other lines have walls do not have sufficient shear capacity to resist the applied force. This has been corrected.

12. Program Version for Saved Files (Change 173)

The program now records the version of the program used to save a project file and shows it in the About Shearwalls box when the file is opened. This feature is primarily used internally at WoodWorks for diagnostics.

 

Shearwalls 9.0.1 – October 8, 2014 - Design Office 9, Service Release 1a

1. Persistence of Manually Input Wall Rigidities (Bug 2895)

Starting with version 9, when manually input rigidities are selected as the rigidity method in the Design settings, the program re-set all relative rigidities to one when distributing loads.

Since load distribution is done before design, it was no longer possible to set manual rigidities that are then used in design, and the manual option was identical to the “equal rigidities” option. This has been corrected and the program again allows you to manually set the rigidity to be used for each wall in the structure.

2. Relative Rigidity as Parameter for Design as Group (Bug 2897)

If you change the manually input relative rigidity for one wall in a standard wall group, the program no longer applies it to all walls in that group, nor does it present a message box warning you of this. Instead, different walls within different groups can have different relative rigidities.

Note that when the Design Setting All shearwalls on shearline have same materials was set, the program did not apply the relative rigidity to all walls within a line walls in a line. The behaviour for design groups is now consistent with that approach. Rigidity usually depends on the geometry of the wall so it cannot be specified for all walls within a group or line containing walls of differing lengths.

The program still includes relative rigidity amongst those parameters in a Standard wall that can be used to create the initial values for a set of walls. However, it no longer includes rigidity among those parameters that define a standard wall when identifying what standard wall a physical wall pertains to.

 

Shearwalls 9.0 – Oct 1, 2014, Design Office 9, Service Release 1

This release corrected the problem with the Design Office installation that disabled the input of .pdf CAD files (Feature 126).  No changes were actually made to the Shearwalls program itself, hence the same version number as the previous version, 9.0.

Shearwalls 9.0 – Sept 17, 2014 - Design Office 9

This is a major release of the software containing many new features and small improvements.

The following table of contents can be used to navigate to detailed descriptions of the program changes.

 

A: Engineering Design. 2

1. Worst Case Design. 2

2. Wall Design Groups (Feature 17) 2

3. Highlight of Failing Walls (Feature 75) 2

4. Design Summary (Feature 138) 2

5. 500mm Stud Spacing for Unblocked Factor (Feature 173) 2

6. Hold-down Offset Subtraction from Overturning Moment Arm (Bug 2731, Change 165) 2

7. Hold-down Force Accumulation Tolerance ( Change 169) 2

8. Non-convergence of Deflection-based Distribution to Segments (Bug 2770) 2

9. Uplift Loads on Walls with Openings (Bug 2744) 2

10. Verification of Stable Design in Final Design Check Iteration (Bug 2743) 2

11. Design for Distribution of Forces to Shearwall Segments Based on Rigidity. 2

12. Output Warnings for Inadequate Stud Thickness for Hold-downs (Bug 2825) 2

13. Hold-down Stud Width for Capacity and Elongation (Bug  2826) 2

14. Levels and Directions for Out-of-Plane and Weak Storey Seismic Irregularities (Bug  2824) 2

15. NBCC Terminology (Change  164) 2

B: Building Model and Program Operation. 2

1. Design and Load Distribution Processing Time. 2

2. Multiple Extend Upwards (Feature 193) 2

3. Accept Design (Feature 153) 2

4. Log File in Viewer (Feature 153) 2

5. Log File Button (Change 120) 2

6. Getting Started Steps (Change 122) 2

7. Crash after Moving Opening then Entering One (Bug 2856) 2

8. Creation of Perpendicular Non-shearwalls (Bug 2880) 2

9. Location of Standard Walls File for Network Installations (Bug 2776) 2

C: Load Generation. 2

1. List of Cities for Default Seismic and Wind Data (Feature 209) 2

2. C&C Loads. 2

4. Crash on Load Generation for Closely Spaced Walls (Bug 2687) 2

5. Crash when Generating Loads on Merged Walls (Bug 2882) 2

6. Torsional Irregularity for Wall Lines with Zero FHS (Bug 2738) 2

7. Message for Applicability of I-15 Method for Multi-block Structures (Bug 2738) 2

8. No Species Group in Initialization File (Change 2738) 2

D: Drawings and Graphical Input 2

1. Import of Bitmap and PDF Versions of CAD Files (Feature 126) 2

2. Adding Openings over CAD Import (Feature 150) 2

3. Graphical Selection of Openings (Feature 23) 2

4. Display of Wall Group Name (Feature 102)* 2

5. Slowdown in Updating the Drawing of Loads (Bug 2750) 2

6. Appearance of Load Arrows (Bug 1952) 2

7. Color of Text in Load Generation Legend (Bug 2815) 2

8. Plan View Update Quality (Change 161) 2

E: Data Input 2

1. Standard Wall Copy (Feature 178) 2

2. Default Load Type when Adding Loads (Feature 141) 2

3. Creating Standard Walls with Unknowns (Bug 2881) 2

4. Default Thickness for OSB Sheathing. (Bug 2805) 2

5. Unknown OSB Interior Panel Markings (Bug 2881) 2

6. Conversion of Imperial Units for Wall Framing Thickness (Bug 2804) 2

7. Tool Tips for Wind Load Generation Controls (Bug 2675) 2

8. Input of Invalid Wall Location (Bug 2754) 2

9. Editable Ply and Panel Marking Input Box (Bug 2807) 2

10. Enabling of Double-Bracket Boxes in Openings View (Bug 2813) 2

11. Wall Framing and Hold-down Behaviour on Multiple Selection (Bug 2816) 2

12. User Interface Rearrangement 2

13. Design Code Clause Number in Design Settings for Collector Force Method for Irregularities  (Change 151) 2

14. Default Setting for Save as Default (Change 159) 2

15. Location of Wall Dead Load Input (Change 153) 2

16. Project Files With Hold-downs Deleted from Database (Bug  2827) 2

17. Message for No Species Group in Database.ini File (Change  167) 2

F: Text Output 2

1. Shear Results Output for  Shearlines which Extend over Part of Structure (Bug 2822) 2

2. Cumulative Storey Shear in Seismic info Table (Change 137) 2

3. Shearwall Wall and Opening Dimensions Table Legend (Change 162) 2

4. Component and Cladding Tables Design Tables (Nug 2885) 2

5. Output of Bx  for Torsional Irregularity (Change 154) 2

6. Design Code Clause in Irregularities Table (Change 152) 2

7. Code reference for Gust Effect Factors in Log File (Change 166) 2

8. Panel Marking in Sheathing Materials Output (Bug 2808) 2

9. Log File for Torsional Analysis Changes (Changes 138-141) 2

10. Shear Design Table Legend (Change 172) 2

11. Default Design Results View (Change 155) 2

12. Blank Page in Output (Change 157) 2

13. Capitalization of Load Case (Change 142) 2

 

A:  Engineering Design

1. Worst Case Design

Previously, when wall parameters were left as unknown, Shearwalls designed separate walls for wind design, seismic design, rigid distribution, flexible distribution, and both force directions – a possibility of 8 designed walls for each physical wall in the structure. In practice, at most 4 walls would be designed, because forces in opposing directions are similar, and often only two or three walls would result. It was left to the designer to compare these walls manually and choose the one that was strong enough for all load cases. If you wanted to see design results for the selected wall, it was necessary to “accept” the design for that case and to run the design again.

Now, the program automatically determines the worst case of wind and seismic, and for opposing force directions, and designs one wall that is evaluated for all these load cases. Optionally, you can also have the program determine the worst case of rigid and flexible diaphragms.

a) Worst Case Wind vs. Seismic Load Case (Feature 12)

i. Shear Wall Design

Previously, the program determined the wall parameters needed to resist the forces from the applied wind loads, and then did so for seismic loads separately. As a result, the program could create separate wall groups for the same physical wall, one for wind design and one for seismic design.

The program now compares the walls designed for wind and seismic and selects the wall that has the highest capacity. That wall is then used to redistribute forces on the line if deflection is the force distribution criterion, and to redistribute forces to the shearlines for the rigid diaphragm procedure.

ii. Output – Shear Design Table

The wall groups are indicated by numbers in the Shear Design table, which are defined in the Sheathing and Framing Materials by Wall Group tables.  For a particular wall, the same number now appears for seismic and wind design; previously they could be different.

In the Critical Response column of the table for wind design, the program outputs an “S” beside the response ratio if the critical case was seismic and the wall had unknown parameters. Similarly, a W is printed beside the column in the seismic table if the critical case was wind.  This alerts you to the reason that a wall might be designed with materials that are much higher than needed to resist the loads from the design case shown. 

The legend has been modified to explain the meaning of these letters.

b) Worst Case Rigid Diaphragm vs. Flexible Distribution Method (Feature 69)

Many designers prefer to consider diaphragms to be semi-rigid, and in the absence of a complex numerical model of the structure, wish to design for the worst case of rigid and flexible diaphragm distribution, to cover the whole envelope of possible diaphragm rigidities. Shearwalls now allows for that approach.

i. Design Setting

A checkbox has been added to the Design Settings called 

 

Worst-case rigid vs. flexible diaphragms (envelope design).

 

The default for new program installations that this setting is on, but this can be changed.  The setting is disabled if you have not chosen to design for both rigid and flexible diaphragms (the choice is in the Structure input).

ii. Shear Wall Design

If the Worst case rigid vs. flexible setting is not selected, program determines the wall parameters needed to resist flexible diaphragm distribution forces, and then does so for rigid forces separately. As a result, the program can create separate wall groups for the same physical wall, one for rigid diaphragm design and one for flexible design.

If the setting is selected, the program first designs a wall for flexible diaphragm forces. When designing for rigid forces, if they are lower than flexible force, the program simply uses the wall designed with the flexible force. If they are higher than the flexible force, it replaces the wall designed for flexible forces with the one designed for rigid forces. For deflection-based intra-shearline distribution, the wall is then processed again for flexible forces on the next iteration of the design procedure, as the distribution of forces within the shearline may change slightly due to the new wall stiffness.

iii. Output – Shear Design Table

The wall groups are indicated by numbers in the Shear Design table, which are defined in the Sheathing and Framing Materials by Wall Group tables. If you have selected the Worst-case rigid vs. flexible diaphragms design setting, then for a particular wall, the same number appears for rigid and flexible design. If that setting is not selected, they can be different.

Please note that if the Worst case rigid vs. flexible setting is set, a the wall materials appearing in table for rigid diaphragm design may have been designed for a higher force for flexible diaphragm design, and vice-versa. If the program designs walls that appear to be much stronger than needed, this is the most likely reason.

c) Worst Case of Opposing Force Directions

It is possible for the force in one direction to be slightly different than the force in the opposing direction. For wind design, this can occur for a mono-slope roof or eccentric ridge line.  For both wind and seismic design, it can occur when forces are distributed due to deflection and there are asymmetries in the hold-down devices or hold-down forces. An example of this is when openings are do not line up and vertical compression forces from the floor above are added to tension forces from the floor below. 

In rare circumstances, such difference could cause the program to design a different wall for the east->west direction than the west<-east direction, and similarly for north-south walls.

i. Shear Wall Design

The program now determines the largest force on any segment in the shearline, in either direction, and designs the wall materials for that force.

ii. Output – Shear Design Table

When different forces existed, two lines of results instead of one were output in the Shear Design table for each wall in the shearline. If different wall materials were selected by the program for these forces, a different wall design group number could be shown for the two directions.

The program still outputs separate design results for the opposing force directions if they are different, but this is to show the performance of the wall with respect to the different forces. The design group number shown for the opposing directions is now always the same. 

d) Worst Case of Wind Shear vs. Wind C&C Design (Bug 2848)

In determining the worst-case wall on the structure, the program considers wind shear, nail withdrawal, and C&C sheathing design.

The procedure has one slight imperfection in that thicker sheathing, which is optimal for out of plane sheathing strength and for shear design, makes for weaker nail withdrawal strength due to reduced penetration. So when determining the strongest wall, one wall may be stronger for suction and for shear but another may be stronger for nail withdrawal. In such a case, the program uses the wall with thicker sheathing. It is extremely rare for the wall to fail for nail withdrawal as a result. 

e) Design Failures

There exists a small possibility that when distributing loads using the rigid diaphragm method to a stronger wall than was designed using that method, the rigid distribution routine could load the shearline to the extent that the wall fails despite being stronger than the one that previously passed. This can happen when a wall designed for seismic is used to resist wind loads (or vice versa), or when a wall designed for flexible distribution is used for rigid diaphragm forces.

Although unlikely, it has the highest chance of happening when using deflection-based design and the effect of increased stiffness is greater than the increase in wall capacity.

If this occurs, the program alerts you to the situation via a note under the Shear Results table. The wording of the existing note that appears if this occurs for other reasons has been modified to take into account this possibility.
The same thing could conceivably happen for the flexible diaphragm method and distribution within a shearline using deflection-based rigidity, but it is highly unlikely because all segments on the wall have the same shear wall materials.

f) Shearline, Wall and Opening Dimensions Table

Because this table no longer shows a list of design groups for each wall, showing at most two for rigid and flexible design, the heading to this column is “Wall group rather than Wall Group(s). A note below the table has been added when worst case rigid and flexible is not selected, explaining why two group numbers may appear. 

2. Wall Design Groups (Feature 17)

The program now allows you to specify that groups of walls with unknown parameters wind up with the same material specification after design. The program designs the wall for the most heavily loaded wall in the group.

For example, all interior walls on a certain level, or all exterior walls in the structure, can be specified to be the same. Previously such walls would often have slightly different material specifications, which is not usually practical for construction.

a)    Standard Walls

The program uses the existing Standard Wall mechanism for this feature. You can indicate which standard wall groups are to be designed as a group, and within the standard wall group, which walls are to be included in the group design. It may be necessary therefore to make more standard wall groups than were previously used to make default walls.

For example, if you had a Standard Wall called Exterior Shearwalls that was used as a starting point for design of all exterior walls, but want the same set of wall materials to be designed on each story of the structure, but possibly lighter walls on the upper storeys, then you would make 4 new groups called Exterior Shearwalls Lev 1, Exterior Shearwalls Lev 2, etc.

b) Design as/in Group Input

A checkbox has been added to the Standard Wall input called Design as a group and in the regular wall input mode called Design in group. The checkbox in the standard wall mode means that all the walls of that standard wall that also have the checkbox checked will be designed as a group in the sense that they will wind up with identical materials after design. Those individual walls that do not have the checkbox checked are treated as if they were not part of a standard wall group.  Those standard walls that do not have the checkbox checked function as current standard walls, that is, as default walls only.

i. Default Setting

The standard wall checkbox will default to being checked if a new standard wall is made. The standard walls shipped with the program will have the checkbox checked by default.

ii. Updates

If you uncheck the Design as a group check box for a standard wall, then all the checkboxes for walls of that group are unchecked and disabled. If you check a standard wall box that had been unchecked, then all of the standard walls in the program are be checked and enabled.

If you select a Standard Wall for an individual wall when previously it had a different standard wall or no standard wall, then the individual wall’s checkbox will be checked and enabled if the standard wall box is checked. If it is not, it is unchecked and disabled.

If you change a wall so that it becomes identical to a standard wall and then becomes one of those standard walls, the checkbox will be unchecked regardless of whether the standard wall Design as Group checkbox is checked or unchecked, but it will still be enabled. This is because the wall was not made a standard wall deliberately, so you are unlikely to want it to be grouped with those walls for design. 

iii. Default Walls

When walls are made in the program using standard walls, then the individual wall’s checkbox will be checked and enabled if the standard wall box is checked. If it is not, it will be unchecked and disabled.

iv. Standard Wall Deletion

If you delete a standard wall, then the program goes through all the walls that had been that standard wall, and unchecks Design in group.

v. Previous Versions

Walls from existing files from versions before the feature was implemented have their individual wall Design in group checkbox unchecked by default.

c) Wall Attributes

Previously, when attributes such as materials or wall type were changed for individual walls, the wall would no longer be identified as being a standard wall. If standard walls are changed, then all the walls that were created with that wall were not identified with that standard wall. For those standard walls designed as groups, this has changed, and membership in the standard wall group persists through material changes. 

i. Change of Wall Attribute

If you change an attribute of a wall that is currently one of a standard wall group, and both the standard wall and the individual wall are to be part of a design group, then the program will issue a warning saying, All walls of the [standard wall group] will also have the selected change. There is a “Don’t show this box again checkbox in the message to allow you to avoid having the box appear repeatedly.

 If you don’t want the attribute to change for all walls in the group, then just change it back to what it was and deselect the Design in Group box for those walls you do not want to change.

If you change an attribute of a wall that is a standard wall but does not have the Design as Group checkbox checked, then the program will allow the change with no message and in most cases it will cause the wall to no longer be part of the standard wall group. No other walls will receive the change.

ii. Change of Standard Wall Attribute

If you change at least one attribute of a wall that has the Design as Group box checked, when exiting the box, the same message as for individual walls appears, saying all members of the Standard Wall group will receive the change, allowing you to suppress further instances of the message.

If the Design as Group box is not checked, then a change in wall attributes will cause all the walls that were previously one of the standard walls to no longer a standard wall, as the program currently behaves.

d) Multiple Standard Walls with Same Materials

Previously, the program would not allow you to create more than one standard wall with the same material specification. For those standard walls that are designed as a group, this restriction has been relaxed in order that you can use for example the same material specification with unknowns that become different wall specifications when the unknowns are determined by the program in order to meet design requirements. 

For example, you can have different standard wall groups on each floor of the building, each with the identical materials when unknowns are included, which however become different walls when the program designs for the different loading scenarios on each floor.

i. Automatic Identification of Standard Wall Group

Currently, if the program identifies that a change in a wall makes it identical to a standard wall, it assigns it to that standard wall. If you have multiple standard walls with the same specification, it randomly chooses which of these standard walls to assign the wall to. This has little impact, because the Design in group is unchecked in this case. You can manually change the standard wall the wall is associated with and check Design in Group if you want it to be grouped with a different wall.

e) Standard Wall File Synchronization

When a file is saved with standard wall groups, and the standard wall definitions are later changed, or standard walls are deleted, while in another project, and the original file is opened up again, some of the grouped walls have no standard wall associated with them.

If this happens, new standard walls are created with the materials from the grouped walls, and given names Std Wall 1, Std Wall 2, etc. These walls are later saved as standard walls that can be opened with any project. You can then either delete them, rename them, or reconcile them with the changed standard walls that were originally used to create them.

f) Design Procedure

After the design iterations, and before the final design check, the program compares the design capacities of all walls in a group. I then the materials of the wall with the highest capacity to all the walls in the group, then recalculates the wall deflections, redistributes loads to the walls, and outputs design tables for the new walls. 

i. Design Failure

It is possible for the new load distribution to create a situation that the critical wall in the design group might elsewhere fail elsewhere on the structure where a weaker wall had passed. When this happens, a warning appears in the Shear Design table of the output.  The existing warning that appears when this occurs for other reasons has been reworded to reflect this possibility,

ii. Wall Grouping

The existing system of comparing all the designed walls to establish design groups with identical materials, which are identified by numbers, has been retained. The fact that walls within a Standard Wall group will have the same materials cause them to be grouped with the same group number.

Walls that are not part of Standard Wall groups are also grouped and assigned group numbers as they currently are.

g) Accept Design

Changes have been made to the recently added Accept Design feature because there are no longer separate designs for wind and seismic, so the choices in the selection menu are now just Rigid Diaphragm and Flexible Diaphragm” rather then Rigid, Wind, etc.

The sub-submenu item has been changed to say Accept from Accept Design.

When you have activated the Worst Case Rigid and Flexible feature, both Rigid and Flexible are checked but disabled, and the Accept item is the only one that is enabled.

h) Output

i. FRAMING MATERIALS by WALL GROUP Table

The name of the Standard Wall associated with a wall group, if there is one, is included in a column that has been added to this table.  It is possible that more than one Standard Wall yields the same materials when designed; in that case the line is repeated with the same group number. If there is no Standard wall associated with the group number because it came from walls that were not grouped, the line appears blank.

The table has been renamed accordingly to FRAMING MATERIALS and STANDARD WALL by WALL GROUP.

ii. SHEAR DESIGN Table

A hat symbol (^) appears beside the wall group number for the wall that is critical for that group, that is, the wall that had the heaviest loading and for which the wall materials designed were used for all other walls in that group.

The legend has been modified to explain this and to refer to Standard Wall groups.

iii. SHEARLINE, WALL and OPENING DIMENSIONS Table

The legend has been modified to refer to Standard Wall groups.

iv. DEFLECTION Table

The legend has been modified to refer to Standard Wall groups.

3. Highlight of Failing Walls (Feature 75)

If a wall failed design for the design case (wind shear, wind C&C, seismic, rigid diaphragm, or flexible diaphragm) shown on the screen, then the failing wall appears in red. The colour for a selected wall, which used to be red, is now orange. If a failing wall is selected, it appears as a darker shade of red.

A note at the bottom of the screen indicates that orange is for selected walls and red for failing walls. It also indicates the design case being shown on the screen.  

4. Design Summary (Feature 138)

To allow you to identify walls and hold-downs that fail design without having to scan the full design results report, the program now includes a design summary. It appears in the Design Results report before the shear results for the first design case (just after the loads are output). In addition, the program alerts you with a pop-up message if any walls fail.

a) Message Box for Wall Failure

If any walls fail for any design case (rigid diaphragm, flexible diaphragm, wind shear, wind C&C, seismic), the program shows a message box on the screen that gives the levels and he design cases  that the failure occurs. It tells you to go to the Design Results or to see the highlighted walls in Plan View (see Feature 75, above)

b) Wall Failure Summary

For each design case (wind shear loads - rigid diaphragm, wind shear loads - flexible diaphragm, components and cladding wind loads - out-of-plane sheathing, components and cladding wind loads - nail withdrawal, seismic loads - flexible diaphragm, seismic loads - rigid diaphragm) the design summary either indicates that there were no under-capacity walls, or gives a list on each level of the names of the walls that failed.

c) Hold-down Failure Summary

For each design case (wind shear loads - rigid diaphragm, wind shear loads - flexible diaphragm, seismic loads - flexible diaphragm, seismic loads - rigid diaphragm) the design summary either indicates that there were no under-capacity hold-downs, or gives a list on each level of the names of the walls that contained under-capacity hold-downs.

d) Table Menu Item

The Go to Table menu that appears when the Design Results are shown now includes an item for Design Summary.

5.  500mm Stud Spacing for Unblocked Factor (Feature 173)

The program now allows input of 500mm (19.2”) stud spacing, corresponding to 1/5th of the length of a standard sheet of plywood. When 500 mm or 19.2” is selected, the program uses the unblocked factor in O86 Table 9.33 for 500 mm.

6. Hold-down Offset Subtraction from Overturning Moment Arm (Bug 2731, Change 165)

The program did not subtract the hold-down offset from the moment arm when calculating overturning hold-down forces, even though O86 9.5.6.1 requires it and that the disabled checkbox in the Hold-down settings indicates that it is to be subtracted.

Since 9.5.6.1 says you should use the centre of the end stud as your hold-down offset for moment arm calculations, we now allow you to use the centre of the end wall stud assembly that you input in Wall Input View for each wall in the structure. A checkbox in the Hold-down settings is used for this. The default value is to be checked.

When drawing, the program now draws the tension side hold-down at the full stud thickness from the wall end, because it depicts the bracket, not the center of the bolt through the studs.   

7. Hold-down Force Accumulation Tolerance (Change 169)

The program now accumulates hold-downs forces from the floor above with the one on the floor below when these forces are that are offset by as much as 1.5 " in plan. This is the minimum distance from wall end.

8. Non-convergence of Deflection-based Distribution to Segments (Bug 2770)

Occasionally, Shearwalls is unable to distribute forces to the shear wall segments by equalizing the deflection of each segment due to non-convergence of the numerical routine used.

a) Warning Message

If this happens, the program now outputs a note below the Shear Design table indicating the affected shearlines.

b) Inconsistency of Deflection and Design Forces

In such a case, the force on the segment used for shear wall design could be markedly different than the force used for deflection analysis. This has been corrected, and they are now the same.  However, it should be noted that these forces do not result in equal deflections on the shearlines, and the value selected is just one in the succession of non-converging iterations that can oscillate between very different values. We recommend turning to capacity-based rigidities for load distribution if this occurs.

9. Uplift Loads on Walls with Openings (Bug 2744)

When uplift loads were added to a wall with openings, the elevation view displays incorrect values superimposed on top of one another. Each opening added to the wall caused an additional increase in the incorrectness of the uplift load magnitude. The incorrect uplift load magnitude was used to calculate hold-down forces, which were shown in Plan View, Elevation View, and the Hold-down Design table.

10. Verification of Stable Design in Final Design Check Iteration (Bug 2743)

The program was doing a full load distribution and wall design during the final design check loop.  The design check loop was intended to use the previous iteration's load distribution and designed walls to verify that the wall design / distribution achieved a stable design. By doing a full load distribution and wall design on the last iteration the verification check was not identifying when the wall design / load distribution does not achieve a stable design, and not issuing the appropriate warning. This has been corrected.

11. Design for Distribution of Forces to Shear Wall Segments Based on Rigidity

The following problems occurred when the Distribute forces to wall segments based on rigidity and the Use shearwall deflection to calculate rigidity Design Settings were both selected. They have been corrected:

a) Selection of Critical Segment in Design for Unknowns (Bug 2730)

 The program did not take into account the distribution of forces on individual shear wall segments between openings when determining the critical segment for design. Instead it considered only the lowest Jhd value from all segments on the wall. As a result, walls with "unknown" material or hold-down choices sometimes failed design when the program should have designed a stronger wall that would pass.

b) Design Ratio and Failure Warnings for Segmented Walls (Bug 2884)

When forces are distributed to individual segments via deflection, in the design loop the program evaluates the wall via the force vs. capacity of the critical segment. However, in the design report, it shows only the force vs. capacity for the entire wall, that is, the sum of the forces vs. the sum of capacities, as per O96 9.5.1. Therefore walls that fail design and can be passed over in the design loop can pass when each parameter is selected by the user.

This has been corrected by showing the design ratios in the output for each segment on the wall, and failure warnings for if any one of them is under capacity.

12. Output Warnings for Inadequate Stud Thickness for Hold-downs (Bug 2825)

If you selected a hold-down that is not rated for the thickness of wall studs at the end of the wall, then the program did not design for that hold-down and it used the displacement over-ride entered in the settings. It issued a warning in the hold-down design and hold-down displacement tables to that effect.

Since the wall studs do not necessarily include “cripple” or “jack” studs beneath the window that can contribute to hold-down strength, the program now issues a warning to the effect that extra cripples or jack studs are needed, and continues with hold-down design using the capacity and displacement for the least thick stud assembly that the hold-down is rated for.  The warning is no longer in red indicating a failed design.

13. Hold-down Stud Width for Capacity and Elongation (Bug 2826)

If there are multiple entries for hold-down capacity for different stud widths, and the entries are listed with the larger stud width before the smaller width and the wall’s stud width is greater than both entries, the program used the capacity and elongation for the smaller stud width even if the larger width was the closer match. This has been corrected.

14. Levels and Directions for Out-of-Plane and Weak Storey Seismic Irregularities (Bug 2824)

Shearwalls sometimes reported the wrong building level or direction for which a Type 5 irregularity (Out-of-Plane) occurred. This irregularity could also be incorrectly allowed or disallowed due to the Weak Storey (Type 6) irregularity as it was using the wrong level or direction. These problems have been corrected.

15. NBCC Terminology (Change 164)

All references in the program to NBCC, meaning National Building Code to the correct acronym for the building code, NBC.

B:  Building Model and Program Operation

1. Design and Load Distribution Processing Time

The time taken to design shear walls and to distribute and draw loads and forces has been markedly improved, by a factor of at least twenty, so that delays that used to occur in the operation of the program have been reduced to manageable levels.

a) Slow Processing Time when Designing Complicated Structures (Bug 1837)

When a project had a combination of many shearlines, many exterior surfaces, many blocks, and multiple stories, the time taken to analyze and design the structure could be very slow, sometimes as much as 30-60 minutes. Such a structure now takes 1-2 minutes. Smaller, less complicated structures also design much faster, so that a building that used to take a few minutes to design now designs in a matter of seconds.

b)  Slowdown in Updating the Drawing of Loads (Bug 2750)

Once loads had been generated, every time you went into Load Generation action or Loads and Forces action, the drawing of the building and loads in plan view would hang for many seconds, especially for complex buildings with a large number of loads. This also happened while you scrolled the view, selected walls, moved the window, edited loads, etc.  

This has been corrected and the drawing of the loads has been accelerated by a factor ranging from a small amount to up to several thousand times, depending on the complexity of the building. The delay in drawing loads is now a fraction of a second and manageable.

2. Multiple Extend Upwards (Feature 193)

The program allows you to extend your walls upwards in stages, that is, extend walls up through a more limited number of levels than to the top of the building. However, in order to maintain a closed envelope, you must always extend the walls through at least one level and cannot build a level from scratch.

For example, for a five storey structure, you can make a floor plan, extend to floor 2, then be on floor 3, make a floor plan, extend only to floor 3 (that is, not at all), then make another floor plan, and extend it from level 4 to 5.  Unlike the current operation, the level indicator in the data bar is active during this process to allow you to do this.

a) Level Inputs

Two inputs, one to show the level that you are on and one to show the level that you are copying it up to, that is the range of levels. The levels are called Current level and Extend to. The Current Level input is always disabled and is there to show you the range. Once the process is complete, it becomes enabled to select levels and Extend to disappears.

b) Operation

If you choose an intermediate storey, or don’t extend at all by selecting the same storey, then press extend, the program then

-       extends to the level selected,

-       creates a new floor plan from the blocks for the next unextended level,

-       sets the current level to the next unextended level,

-       sets the in Extend to to the highest level,

-       outputs a prompt explaining how to proceed.

If you extend to a level that is one below the highest level, the program in fact extends to the highest level and copies the next-to-highest level to that level.

c)  Undo and Redo

The Undo and Redo commands are active during this process and allow you to go back and try again if you have made a mistake.

3. Accept Design (Feature 153)

The other WoodWorks programs, Connections and Sizer, allow you to transfer the design results from a successful design back to the input fields, replacing unknown values on those fields. This allows you to experiment with and tweak your design, for example to use fewer different types of materials at the expense of optimal strength in some areas.

This ability has now been added to the Shearwalls– you can transfer the design results for all walls in the structure from one of the four design cases – combinations of Rigid or Flexible Diaphragm, and Wind or Seismic.

a) Design Case Menu

A sub-menu now appears in the Action menu called Accept Design. When dropped down, it gives the choice of the four design cases for which to accept design.

If one of the Design Cases is selected in the Accept Design Menu, loads from that design case is shown on the screen. However, this is not reciprocal, if you select another design case via the Show menu, the Accept Design case does not change. In this way, you can always check the design case that was used to accept the design.

b) Accept Design Command

The Accept Design command is invoked either from the Accept Design submenu, or via a button at the far right of the main program toolbar.

c) Re-running Design

When you rerun design after Accepting design, the program may fail for other design cases than the one accepted, because the unknown values have been replaced by ones strong enough for that design case but not for others. If that is the case, you can reset some parameters to unknown, then re-run design and then select the critical case for “Accept Design”.  After a few iterations of this procedure, you can achieve a design that satisfies all design cases.

d) Non-Shearwalls

Non-shearwalls are updated only if they were designed for C&C wind loading.

4. Log File in Viewer (Feature 208)

The log file which provides load generation and rigid diaphragm analysis details has now been integrated into the program and appears in a window within the program framework. Previously the program invoked the Notepad program to show the log file results. The window is called Load Generation and Torsional Analysis Details. The menu and status bar descriptors have also been updated.   

5. Log File Button (Change 120)

A button has been added to the main program tool bar to invoke the log file, and to toggle the log file viewer on and off. The log file button has been removed from the toolbars attached to the windows for Plan, Results, and Elevation views.  

6. Getting Started Steps (Change 122)

The Getting Started dialog has been updated to reflect the current state of the program. The text shown for Roofs and Generate Loads has been changed and a new step, Step 14, Log File Output, has been added.

7. Crash after Moving Opening then Entering One (Bug 2856)

Occasionally, after moving openings on upper-level storeys, then creating a new opening on the same wall, the program would crash. This has been corrected.

8. Creation of Perpendicular Non-shearwalls (Bug 2880)

After one segment of an exterior non-shearwall is perpendicular to the wall to create two perpendicular joining segments, those segments are designated shearwalls rather than non-shearwalls. They otherwise had the same materials as the non-shearwalls. This has been corrected and they remain non-shearwalls.

9. Location of Standard Walls File for Network Installations (Bug 2776)

For network installations, the file that stores the standard walls was previously located on each local client machine. The standard walls file is now located on the network server in the same location as the materials and hold-down databases.  This was needed now that the standard wall groups are used for design grouping.

C:  Load Generation

1. List of Cities for Default Seismic and Wind Data (Feature 209)

The list of cities shown in the Default Settings from which you select the location for your wind speed q and seismic parameters Sa (T = 0.2, 0.5, 1.0, 2.0) has been expanded, Previously it included a list of 80 major centers across Canada. Now it includes all the municipalities listed in Appendix C of NBCC, a total of 670 cities.

A dropdown list of all provinces and territories has been added to the program, and you first select your province and a list of cities in that province appears, with the capital city appearing by default. You then pick the city closest to your design location.

Shearwalls project files from previous versions will use the city closest to the one in the old list, for example Kitchener-Waterloo will now be Kitchener and Chicoutimi is now Saguenay. The new list of cities also contains the proper spelling of cities in terms of including accents and hyphens.

2. C&C Loads

The following improvements have been made to the treatment of Component and Cladding loads and C&C design.

a) C&C Loads Per Wall Line (Feature 206)

Because different wall lines can have different reference heights h because they are on different blocks, but be on the same face of the building in terms of N, S, E, W directions, the program now assigns separate C&C loads to each wall line. If the wall line includes walls from more than one block, the highest C&C load from the blocks is used.

As a result, C&C loads are shown in plan view on each wall line with exterior walls. Previously only one C&C load was shown for each building face.

b) Windward Pressure (Feature 207)

Previously the program used the worst case of the outward (suction) C&C pressure for both sheathing strength and nail withdrawal design, although it is possible for the combination of windward external pressures and negative internal pressure to be greater than leeward internal pressures and positive internal pressure. This caused somewhat conservative design for nail withdrawal, which is applicable only when exterior forces are outward. 

Furthermore, some users were confused by the discrepancy between their calculations for windward pressures and the C&C pressures on the screen for a windward load direction shown.

Accordingly, Shearwalls now calculates the windward and leeward pressures separately and uses the leeward for nail withdrawal design.

i. Plan View

Shearwalls now shows the windward pressure if the displayed wind direction is directed towards a surface, e.g. for the west face for west to east loads. It previously showed the leeward (suction) pressure.

ii. Elevation View

Both the leeward and windward pressures are now shown in elevation view.

iii. Design

The worst of leeward and windward pressures are used for sheathing design. Only leeward pressures are used for nail withdrawal.

c) Reference Height for Ce (Bug 2500)

The reference height used for calculation of windward velocity pressure coefficient Ce is now the actual height at the top the level in question, rather than the eave height of the structure. This applies to both external and internal pressures. As the Ce factor at the 20m level is 0.82, and the minimum Ce is .70, the C&C loads can be conservative by as much as 17% on the lower levels, however, since the C&C load on lower levels does not tend to govern because of the accumulated shear forces on lower levels, this change has little effect for most designs.  

3. Leeward I-!5 Method Reference Height for Ce (Bug 2810)

Starting with version 8.11, the   program was using the eave height of the building as the reference height for h for calculating leeward Ce for the I-15 method, however, Commentary I- 7 (b) says to use 1/2 the building height. This is a conservative bug effecting taller structures, as the minimum value of 0.7 for rough terrain and 0.9 for open terrain is imposed for shorter structures. The bug affects buildings taller than 12.5 meters for rough terrain and buildings greater than 6 metres for open terrain.

For a 20-meter building, for rough terrain the program was using a .82 Ce when it should be 0.7, for a 17% conservative error, and for open terrain, it is using 1.15 when it should be 1.00, for a 15% error. This has been corrected.

4. Crash on Load Generation for Closely Spaced Walls (Bug 2687)

The program sometimes crashed during seismic load generation when walls are positioned such that they could belong to more than one shearline.

5. Crash when Generating Loads on Merged Walls (Bug 2882)

Starting with version 8.3, if walls are segmented then merged again, the program crashes when generating loads. This has been corrected.

6. Torsional Irregularity for Wall Lines with Zero FHS (Bug 2738)

When determining the deflections on extreme shearlines to derive the Bx from NBC 4.1.8.11 (9) for Irregularity 7 – Torsional Sensitivity, the program was failing to identify those exterior wall lines that do not have full height sheathing, so are not in fact shearlines. It was assigning zero storey drift at the building edge in those cases, which also caused the program to be more likely than it should assign a high Bx.

Now, if the outermost wall lines do not have full height sheathing, the program uses the next closest shearline with full height sheathing, which may in fact consist of interior walls.

7. Message for Applicability of I-15 Method for Multi-block Structures (Bug 2738)

The message about applicability of I-15 method for multi-block structures no longer has the comment about the Cp factors on the block the wall was originally part of, which was rendered obsolete by the fix to Bug 2473 in version 8.2, below.

8. No Species Group in Initialization File (Change 2738)

If the installation does not have a current initialization file for the materials database (database.ini), so that the species group is not identified, the program now uses a stud density of 0.42 corresponding to S-P-F for anchorage deflection calculations. Previously the program would crash. This problem would not ordinarily be encountered by regular users of the program and was a problem primarily for internal testing.

D:  Drawings and Graphical Input

1. Import of Bitmap and PDF Versions of CAD Files (Feature 126)

Previously, the program allowed input only of Windows Metafile (.wmf) or Enhanced Metafile (.emf) file formats for CAD drawings to use as a template to draw your structure. Now, the program allows you to input bitmap (bmp) and portable document format (pdf) files. The program converts the pdf to a bitmap before drawing it.

a) Input

The CAD Import Wizard for importing of the CAD drawings has been updated to allow the following file types:

 

Metafiles (*.wmf, *.emf)

Bitmaps (*.bmp)

PDF (*.pdf)

b) Operation

The operation of the program is the same for bitmap files and pdf files converted to bitmaps as it is for the metafiles the program was previously restricted to.

2. Adding Openings over CAD Import (Feature 150)

As it was difficult to see openings on imported CAD drawings as the solid shear walls in plan view obscured them, the drawing for the openings action when CAD drawing is showing has been modified to allow you to see openings. Segmented shear walls are transparent with diagonal lines. Perforated walls have hatches and the non-shearwall is blank as before. If there is no CAD import showing, then shear walls are shown in solid colour as before.

3. Graphical Selection of Openings (Feature 23)

Previously, and opening could only be selected via a drop list in the Opening Input form. Now in the Openings action of Plan View, if you select anywhere within the thickness of the wall over the extent of any of the openings, then the opening selected is the one available for editing in the input form.

4. Display of Wall Group Name (Feature 102)*

The program now allows you to display the name of the standard wall used for each wall in both Plan view, which is now also the wall design group. This is controlled by a checkbox in the Display group of the Options setting. It defaults to being checked. If all walls on a shearline have the same materials, the name is shown only once.

5. Slowdown in Updating the Drawing of Loads (Bug 2750)

Once loads had been generated, every time you went into Load Generation action or Loads and Forces action, the drawing of the building and loads in plan view would hang for many seconds, especially for complex buildings with a large number of loads. This also happened while you scrolled the view, selected walls, moved the window, edited loads, etc. 

This has been corrected and the drawing of the loads has been accelerated by a factor ranging from a small amount to up to several thousand times, depending on the complexity of the building. The delay in drawing loads is now a fraction of a second and manageable.

6. Appearance of Load Arrows (Bug 1952)

For large structures, the arrows in Plan view representing applied loads became much more widely spaced than for smaller structures, and the arrowhead was not visible. This has been corrected and the appearance of the load arrows is similar for large and small structures.

7. Color of Text in Load Generation Legend (Bug 2815)

The Unfactored generated shear load and Vertical elements required items in the legend that appears on load generation are now coloured blue like the rest of the legend, not orange.

8. Plan View Update Quality (Change 161)

The plan view now draws more smoothly without flashing on changes or when scrolling.

E:  Data Input

1. Standard Wall Copy (Feature 178)

Previously, to create a copy of a Standard Wall was done in a roundabout way that not all users were aware of. (by pressing Add, then selecting from a list of Standard walls).   To make it more evident, we added a Copy button to allow you to copy an existing Standard wall. You must make at least one change to this standard wall before it can be saved.

The old way of copying a Standard wall still exists alongside the new one for those users who are more comfortable with it.

2. Default Load Type when Adding Loads (Feature 141)

The program used to revert to the Dead load type each time you added a new load. Now it uses the type of whatever load is selected in Wall Input View, which is the last load previously added. This allows you to enter multiple loads of the same type without resetting the load type on each one.

Note that the very first load you enter will now default to the type of the first generated load in the list, instead of Dead. If there are no generated loads, then Wind shear will be the type of the first load entered.

3. Creating Standard Walls with Unknowns (Bug 2887)

Sometimes when trying to save a new standard wall with some parameters set as "unknown", the program would not allow it, presenting a message box saying that all fields had not been filled in. This happened frequently for OSB materials and occasionally for other materials, and has been corrected.

4. Default Thickness for OSB Sheathing. (Bug 2805)

The program defaulted to a particular panel marking when OSB was selected, rather than to Unknown as it does for other inputs, and to a particular thickness when a panel marking is selected, without even allowing for Unknown thickness.  This has been corrected and when OSB is selected, the panel marking and thickness default to Unknown.

5. Unknown OSB Interior Panel Markings (Bug 2881)

It had been possible to select "Unknown” as the Panel marking for OSB for interior wall side. Unknowns are not supposed to be in the interior wall selections because the program does not design for unknowns on the interior side unless both sides are the same.

Selecting "unknown" resulted in a zero shear deflection for that wall to be zero. Shear deflection is ordinarily only a small component of deflection, so the impact of selecting unknown was often negligible.

6. Conversion of Imperial Units for Wall Framing Thickness (Bug 2804)

For imperial units, a value typed into the Framing "Width d" is interpreted by the program as being a metric value and immediately converted to imperial by dividing the value by 25.4. This incorrect value was then used for design. This has been corrected.

7. Tool Tips for Wind Load Generation Controls (Bug 2675)

When you hovered your mouse over the input controls of the Wind Loads group of the generate loads box, small “tool tip” messages appeared, but they did not appear for the seismic loads controls or other buttons in the dialog box.  In addition, the Exclude roof portions checkbox mistakenly gave the message for C&C loads.

Messages have been added for all inputs in this box and the Exclude roof portions message has been corrected.

8. Input of Invalid Wall Location (Bug 2754)

Changing the location of a wall via the input field in the Wall Input dialog of a wall to a location that was invalid because it is outside the building perimeter, intersects with another wall, etc., caused the program to crash. The program now shows an error message and does not allow the wall to be made.

9. Add Load to Selected Wall (Change 254)

If no wall was selected and Selected wall was chosen in the Apply to... combo box when adding a new load, a large value automatically appeared in the From X= and To X= fields. Furthermore, you are allowed to enter a load which appeared on a random building face. 

The program has been changed to revert to the previous Apply to... selection in this case.

10. Editable Ply and Panel Marking Input Box (Bug 2807)

Starting with version 8, the field that is used for Plywood plies and for OSB Panel marking is editable, when it should be a non-editable selection list Typing data into this box did not cause a problem; the program simply ignored it and used the default for the designed thickness.

11. Enabling of Double-Bracket Boxes in Openings View (Bug 2813)

In openings view, if no wall is selected, all inputs were greyed out except for the two double-bracket checkboxes at the bottom. With no wall selected, or with a wall with no openings selected, clicking on one of these the double bracket checkboxes caused a crash. These controls are now disabled when no walls are selected, and will not cause a problem when clicked.

12. Wall Framing and Hold-down Behaviour on Multiple Selection (Bug 2816)

When multiple walls with varying properties are selected, none of the fields on the Framing or Hold-down sections of Wall Input View were set be blank to signify an indeterminate selection. This does not currently happen for any field in the Framing or Hold-down sections in Wall Input View, instead showing the value of the most recently selected wall. This is purely a display issue; the actual properties of each wall are correctly maintained.

13. User Interface Rearrangement

The input fields in throughout the user interface have been rearranged somewhat for better alignment, to ensure that all data selections are completely visible in all boxes, that dropdown lists drop down to reveal all choices without scrolling, correct minor typos, etc.

In the Wall Input View, the position of Thickness and Plies inputs have been reversed to better reflect the interdependency of these inputs.

14. Design Code Clause Number in Design Settings for Collector Force Method for Irregularities (Change 151)

The reference to the design code clause 4.1.8.15(6) in the Design Settings about the applicability of capacity-based collector forces for irregularities has been changed to the correct 4.1.8.15.(4). This was due to a renumbering for NBC 2010 vs 2005.

15. Save as Default for New Files (Change 255)

The following settings were not being saved as defaults when Save as default for new files was selected.

-        Line 4 of company information under Company Information

-        Worst-case rigid vs. flexible diaphragms in Design Settings

This has been corrected.

16. Moisture Conditions Input on Design Code Change (Change 256)

When the Design Code changed from CSA O86-09 to CSA O86-14, and vice versa, the nomenclature for the moisture conditions was not being updated until you selected OK and then opened the design settings again. This has been corrected.

17. Default Setting for Save as Default (Change 159)

The default setting for Save as default for new files for Default Values and Company Information settings has been changed from being unchecked by default to being checked by default.

18. Reset Original Settings (Change 257)

a) Moisture Conditions

Fabrication and In-Service Moisture in Design Settings were not being reset to their original value after you reset original settings.

b) Display Gridlines

The input for gridline interval next to Display gridlines in the Plan View settings Elevation View settings remained disabled if Display gridlines was not checked before you reset original settings.

c) Snap Increments

The Snap Increments input in Plan View and Elevation View settings was not being re-enabled if the Display gridlines was not checked before you reset original settings. It is now enabled after the reset because Display gridlines is checked in that case.

d) Imperial Formatting

If you selected imperial units and then resets to original settings, the unit system changed back to Metric, but the Distance, Thickness and Force combo boxes remained enabled. They are now disabled when the unit system is Metric.

19. Fastener Length and Diameter Input for Power-driven Nails (Change 258)

-        For power-driven nails, an error message would appear indicating the fastener length is too small when the fastener length field lost focus and you had selected unknown fastener length. This message is no longer displayed under this circumstance.

-        When fastener diameter loses focus and the user has selected unknown diameter, the diameter would automatically be set to 0. This issue has now been fixed.

-        The progam allowed input of a zero fastener diameter but would design as if it was unknown. Now if you enter a fastener diameter of 0, the Diameter input automatically changes to Unknown.

20. Minimum Nail Diameter for Power-driven Nails (Changes 260 and 261)

The software placed a minimum requirement on the diameter of power-driven nails to be 2.84 mm when deflection analysis is enabled and 2.0 mm otherwise, and showed. The diameter of power-driven nails must now be greater than or equal to 2.0 mm regardless of whether deflection analysis is enabled.

Furthermore, the message saying Nails less than [2.0", 51mm] in length … has changed to Nails less than 2.0" in length

21. Asterisk Next to Framing Thickness and Width (Change 262)

In the Wall Input dialog, the Thickness and Width of wall studs can be entered by the user as well as selected from a list in the wall input dialog, but did not have an asterisk next to them like the other editable fields. The asterisk has been added.

22. Wall Dead Load Input (Change 153)

The input for creating special wall dead loads for Jhd calculations was in the wind section of the Load Generation dialog, when it applies to both wind and seismic. This has been corrected.

23. Project Files with Hold-downs Deleted from Database (Bug 2827)

When loading a project file that contains hold-downs that don’t exist in the current hold-down database, the missing hold-downs were added to the database, but the Cap S-P-F field is populated with a nonsensical value. This has been corrected.

24. Message for No Species Group in Database.ini File (Change 167)

If you do not have a current database.ini file so that the species group is not identified, an error now appears on the screen and a stud density of 0.42 corresponding to S-P-F is used for anchorage deflection calculations. Previously the program would show nonsensical hold-down design, which also affected deflection calculations.

Please note that if this situation occurs, the program repeats the message many times. If you continue to dismiss the message, the design will eventually complete normally. This will be corrected for the next version of the Shearwalls.  The situation that an incorrect database.ini file is on the computer ordinarily exists only in internal testing environments.   

F:  Text Output

1. Shear Results Output for Shearlines which Extend over Part of Structure (Bug 2822)

The program output only one line of shear results data when there is only one shear wall on the line, on the assumption that the information for the line will be identical to that for the wall. However, when the shearline did not extend the whole distance between exterior walls, the shearline length is different than the wall length. The V/L value shown in the shear results output was that for the shearline, that is, the diaphragm shear flow, and not the design shear flow that is needed for the wall. The design ratio therefore did not correspond to the force V/L and the resistance Vr/L values shown in the line.

This was a display issue only, not affecting design, and has been corrected.

2. Cumulative Storey Shear in Seismic info Table (Change 137)

The value of storey shear for All levels has been removed from the Seismic Info table. Below the table, the following lines now appear

Storey shear – Sum of factored, vertically accumulated shearline forces on level, including torsional effects.

Total unfactored base shear[value]

3. Shear Line, Wall and Opening Dimensions Table Legend (Change 162)

The Shear Line, Wall and Opening Dimensions table legend has been updated to make it more readable and fix minor typos. Each item now appears on a separate line, similar to other legends. Improved explanations are given for wall groups and wall length.

4. Component and Cladding Design Table (Bug 2885)

The following corrections have been made to the Components and Cladding design tables that show out-of-plane sheathing and nail withdrawal design:

a)  Interior Walls on Same Line as Exterior Walls

When a shearline goes from the interior to the exterior of the structure, the program output a line of design results for walls that are on the interior of the structure and are not loaded. Those lines would show zero nail withdrawal force but non-zero sheathing force. These lines have been removed.

b) Duplicate Entries for the Same Wall Group

The program output a line of data for each shear wall in a line, however showed results by wall group rather than by individual walls. Therefore there were duplicate lines when more than one wall on a line had the same wall design group. This has been corrected and the program shows only one line for each design group on a shearline.

5. Output of Bx for Torsional Irregularity (Change 154)

If there is a torsional irregularity (No 7), the program now outputs the Bx value that caused the irregularity, as defined in 4.1.8.11(9). It appears in a note under the Seismic Information table.

6. Design Code Clause in Irregularities Table (Change 152)

The notes to the irregularities table had the following mistakes, which have been corrected: 4.1.8.15-6 was changed to 4.1.8.15-4 ; 4.1.8.15-2  changed to 4.1.8.15-5, and 4.1.8.15-2 changed to 4.1.8-7.

7. Code reference for Gust Effect Factors in Log File (Change 166)

The NBC reference for gust effect factors Cg and Cgi have been corrected from 4.1.7.6 a) , 4.1.7.6 b) and 4.1.7.6 c) to  4.1.7.1.(6)(a), 4.1.7.1.(6)(b), and 4.1.7.1.(6)(c). 

8. Panel Marking in Sheathing Materials Output (Bug 2808)

The panel marking in the notes to the Sheathing materials table was repeated for each wall that has that panel marking.  It is now output just once.

9. Log File for Torsional Analysis Changes (Changes 138-141)

The following problems with the Torsional Analysis section of the log file have been corrected:

-         The program output information at the head of the torsional analysis section of the log file about flexible analysis even if it was not done because there are no seismic loads.

-         Flexible seismic design was still performed when it is not possible to do torsional analysis because of lack of shear walls.

-         The explanation about Flexible Seismic appeared of context at the top of the file log file section on torsional analysis, not on every floor as it should.

-         The note for accidental eccentricity appeared for seismic even though it is about wind.

-         The line for wind loads showed the building dimension perp to force and says that the accidental eccentricity is 10D when there was no eccentricity.

10. Shear Design Table Legend (Change 172)

In the legend to the shear design table, the design code reference for O86 section 9.4.5.2 has been changed to Figure 9.4.5.2, the description of Fv/V has been clarified, and the reference to 9.5.1(a) has been moved from Shearlines to Walls.

11. Default Design Results View (Change 155)

When the Design Results button is pressed, the default view is now 'Preview" which shows a full page of design results, rather than "Wide View”, which fills the horizontal extent of the window, usually zooming in on the top part of the page.

12. Blank Page in Output (Change 157)

The blank page that was print out at the end of the Design Results has been removed.

13. Capitalization of Load Case (Change 142)

Changed e.g Low-rise case A to Low-rise Case A.

 

Older Versions

 

Shearwalls 8.4  – WW 8, SR-4

    Shearwalls 7.2 – WW 7, SR-2

Shearwalls 8.3 / 8.31 – WW 8, SR-3

    Shearwalls 7.1 - WW 7 SR-1

Shearwalls 8.2 – WW 8 SR-2

    Shearwalls 7.0 - WW 7

Shearwalls 8.11 – WW 8 SR-1

    Shearwalls 2002a – WW 2002 SR-1

Shearwalls 8.0 – WW 8

    Shearwalls 2002 – WW 2002

Shearwalls 7.22 – WW 7, SR-3

    Shearwalls 99 – WW 99

Shearwalls 7.21 – WW 7, SR-2a

    Shearwalls 97

 

 

Shearwalls 8.4 – Design Office 8, Service Release 4 – September 13, 2013

1. Update of Inputs Related to Hold-downs (Bug 2683)

When the All shearwalls on shearlines have same materials setting is selected, making changes to the Hold-down, Double-bracket, Apply to openings, Number of end studs#, and Hold-down configuration options in wall input view had no effect. The program merely reverted to the previously selected value. This has been corrected.

2. Moving Wall Lines with User Applied Forces (Bug 2676)

Starting with version 8 of the program, moving a wall that is on a shearline with a directly applied shearline force caused the program to crash. This has been corrected.

3. Update of Unknown Nail Spacing Input (Bug 2667)

When Both sides same is selected, the edge spacing did not include the Unknown option, and this persisted for both exterior and interior side when the checkbox was deselected. This has been corrected, and Unknown is again allowed when both sides are the same.

4. Nonsensical Values for Anchorage Deflection (Bug 2677)

Under certain circumstances, the program reported extremely high negative values for anchorage deflection in the Hold-down displacement table. These unrealistic displacements were used in the calculations for deflection, creating nonsensically high deflections.

This has been corrected. It happened under the following circumstances:

a) Zero Force on Segment

When the distribution of forces within a line resulted in zero force on a segment, because other stiffer segments draw the entire load. 

b) Negative Uplift

When there is no uplift force at a location, that is, the counteracting dead load and/or compressive force from above is greater than the overturning force.

 

Shearwalls 8.31 – Design Office 8 Service Release 3 – March 12, 2013

Please also consult the entries for version 8.3 below to view all the changes since the last version released to the public.

1. Uplift Forces Shown in Hold-down Displacement Table (Bug 2641)

The values shown in the Hold-down displacement table for uplift force P were mistakenly showing forces factored for Ultimate Limit States (4.2.4.1), whereas deflection calculations use serviceability limit states (4.2.4.2). As a result, it was possible to have a positive load showing in the table, but zero shown as the elongation, because the serviceability-factored load is negative and not acting as an uplift load.

This has been corrected and the forces showing are those factored for serviceability limit states. Note that the value used for determining the amount of hold-down deflection is in fact ultimate limit state, because it is compared to the hold-down capacity for ULS to determine the proportion of maximum elongation. Otherwise, all, values used for hold-down displacement calculations are SLS.

The ULS values are shown in the Hold-down design table.

2. Serviceability vs. Ultimate Limit States in Table Legends (Bug 2641)

The legends to the following tables for wind design have been changed to make it clear whether loads and forces are factored for ultimate limit states (ULS), serviceability limit states, or unfactored, and whether they include an importance factor if otherwise unfactored:

Wind Shear Loads

Wind Uplift Loads

Wind C&C Loads 

Shear Design

Deflection

Hold-down Displacement

3. Directionality of Uplift Wind Loads (Bug 2638)

a) Blank Input for Wind Uplift Force Direction

Starting with version 8.1, we allow the wind uplift forces to be entered for each wind direction separately, but by default, when an uplift load was selected, nothing appeared in the wind direction box. If you proceeded to enter the loads without selecting a direction, or both directions, then the wind uplift did not get included in the combined hold-down forces, and the separate wind uplift component of the hold-down force that was shown in elevation view and in the output report was unreliable.   

In addition, a load entered with blank direction showed up as blank in the Load Input dialog edit field, E->W in the load list, and Both directions in the load list in the output report. In fact, it acted as none of these.

The default showing in this box is now “Both Ways”, and it is never allowed to be blank.

b) Display of Uplift Loads Entered in Both Directions

If a selection was made for the wind direction before adding the load, the combined hold-down forces were correct; however the uplift component appeared in elevation view for both directions, when it shouldn’t have. 

Different loads entered west to east and east to west (the usual case) were shown superimposed and thus garbled in plan view and in elevation view, along with the uplift components of the hold-downs.

These problems have been corrected.

c) Editing Wind Uplift Loads

The following problems in the Load Input screen used for editing existing loads were corrected: 

All loads showed up in the load list as E->W, even if they were W-> E or Both Ways.  

An E->W load selected showed the direction in the edit box as blank.  

4. Restriction of Shearwall Materials when All Segments have Hold-downs (Bug 2625)

The program restricts the nail spacings available for selection to be at least 100 comply with O86 9.4.5.5 a) when you have indicated in the design settings you want the program to apply these material restrictions. However, it does so even when you have indicated in the Hold-down configuration in Wall Input view that hold-downs are on all segments, so that Jhd cannot be less than one, as 9.4.5.5 stipulates.

It is likely that the program applies other restrictions on nail size and sheathing capacity in this case as well.

It was possible to get around this problem by changing the design setting so that materials are not restricted; however this affected all walls, even those that have anchorages.

This has been corrected and the program does not apply material restrictions to walls that have hold-downs on all segments.

5. Apply Load Change Message (Change 119)

After first entering the Load Input view, changing loads prompted you to apply changes when none had been made. This has been corrected.

6. Seismic Load Generation Input Typos (Change 121)

The spelling of Self-weights has been corrected from Self Weights. The “Generate building masses first…" section title has been extended to fit the ellipses.

7. Getting Started Steps (Change 116)

The Getting Started dialog has been updated to reflect the current state of the program. The text shown for Roofs and Generate Loads has been changed and a new step, Step 14, Log File Output, has been added.

 

Shearwalls 8.3 – Design Office 8 Service Release 3 – Feb 27, 2013

This version of Shearwalls was released to only a limited number of users for use in a training seminar. The changes listed here are also in the 8.31 version of the program released to the general public.

The links below lead to descriptions of the changes.

 

A: Component and Cladding (C&C) Design. 1

1. Update to CSA O86-09 for Sheathing Strengths for C&C Design (Bug 2628) 1

2. Sheathing Strength Values for C&C Design. 1

3. C&C Design Table in the Results Output 1

B: Wind Load Generation. 1

1. Interior Zone C&C Loads for the I-15 Method (Bug 2633) 1

2. Cp and Cg Factors in the Log File for I-15 Method C&C Design (Bug 2635) 1

3. Wind Load Generation Log File Legend (Bug 2635) 1

C: Load Distribution. 1

1. Accumulation of Direct Shearline Force for Seismic Design (Bug 2630) 1

2. Distribution Method for Seismic Direct Shear Forces (Bug 2632) 1

 

A:  Component and Cladding (C&C) Design

1. Update to CSA O86-09 for Sheathing Strengths for C&C Design (Bug 2628)

a) Plywood

The allowable Component and Cladding (C&C) plywood loads have been updated to new values from the CSA O86 2010 Tables 7.3A-7.3B, from the O86 2001 values that were being used.

The following materials have been added:

-        3-ply 12.5 mm and 6-ply 15.5 mm plywood, for both Doug-fir (DF) and Canadian Softwood Plywood (CSP).

For the following materials, allowable strengths have increased for at least one stud spacing:

-        DF:  18.5 mm, 7 ply, 0° (horizontal orientation);

-        CSP: 3-ply 7.5 mm and 9.5 mm; 4-ply and 5-ply 12.5 mm°; 5 ply 15.5 mm; 7-ply 18.5 mm; all 0°.

For the following materials, allowable strengths have decreased for at least stud spacing:

-        DF: 4-ply 15.5 mm, 0°; 5-ply and 6-ply 18.5 mm, 0 and 90°.

-        CSP: 3-ply, 9.5 mm, 90°; 4-ply and 5 ply 15.5 mm, 0°; 5-ply and 6-ply 18.5 mm, 0 and 90°.

Note that CSP 5-ply, 15.5 mm, 0° is in both lists because it decreased for 304.8 stud spacing and increased for 406.4 and 609.6 spacing.

b) OSB

The OSB Type 1 material has been removed, as it is no longer in CSA O86. It had been in table 7.3C

The Construction OSB values, which were in Table 7.3D, did not change for CSA O86 2010 Table 7.3C

2. Sheathing Strength Values for C&C Design

a) 18.5 mm, 7 ply Doug Fir Plywood (Bug 2629)

In generating the allowable C&C loading on of horizontal Douglas-fir plywood 18.5 mm x 7 plies, a bending strength mp’ value of 100 n/mm/mm was used, instead of the correct 1100 from Table 7.3A, 0° orientation. The bending strength was correspondingly 11 times lower than it should be, and the allowable loads 7-11 times lower depending on stud spacing.

b) 9.5 mm 2R24 OSB (Bug 2631)

The allowable C&C load for 9.5 mm 2R24 OSB sheathing was 7.4 when it should have been 7.94. This has been corrected.

3. C&C Design Table in the Results Output

a)  Nail Withdrawal Design Ratio (Bug 2637)

The design ratio in the Design Results output for nail withdrawal shows the end zone ratio for both end zones and interior zones. It now shows the correct ratios.

This problem did not affect design, as the end zone ratio is used for nail design.

b) Sheathing Strength Design Code Reference (Change 132)

In the legend a reference to CSA O86 Tables 7.3A-C was added, with an explanation of the bending and shear criteria used.

c) Precision of Imperial Nail Withdrawal Values (Change 130)

The number of digits precision for Imperial nail withdrawal force and capacity has been changed from whole pounds to 10ths of a pound.

d) Design Code Reference for Nail Withdrawal Capacity (Change 133)

The design code reference for nail withdrawal capacity was mistakenly showing 10.9.4, when it should be 10.9.5. This has been corrected.

B:  Wind Load Generation

1. Interior Zone C&C Loads for the I-15 Method (Bug 2633)

Starting with version 8.2 of the program, for the I-15 (all heights) wind load generation method, the program was generating interior zone Component and Cladding (C&C) loads using the 1.2 Cp* coefficient from Figure I-8 and end zone loads with the 0.9 coefficient when it should be reversed.  These loads appear in plan view, elevation view, and the C&C table of the design results.

As a result, the program designed for nail withdrawal for lighter than expected end zone loads, but may show a failing design ratio in the output for the heavier than expected interior zone loads. It conservatively designed for sheathing strength using heavier than expected interior loads.

2. Cp and Cg Factors in the Log File for I-15 Method C&C Design (Bug 2635)

a) Combined vs Separate Cp and Cg

The Component and Cladding (C&C) loads for the NBC Commentary I - 15 method in the log file showed a combined pressure coefficient and gust factor CpCg, when in fact they are separate factors, similar to the main shear force resisting system (MWFRS) factors for this method. They are now shown as separate Cp and Cg factors.

The combined internal factor CgCpi is also now shown separately as Cgi and Cpi.

b) Inclusion of Internal Factors in External Factors

The factor showing was the difference between external and internal forces (NBCC 4.1.7.1 3)), which was contradicted by the legend to the table. It now shows the external coefficients only (4.1.7.1 1)).

c) Inclusion of Ce for Internal Factors

The combined internal factor mistakenly included the value of exposure factor Ce for internal pressures, but this has been resolved by splitting the combined factor up.

3. Wind Load Generation Log File Legend (Bug 2635)

The legend in the log file which defines the symbols used for wind load generation procedures has been improved in the following ways:

-        Separate legends for I-7 and i-15 wind load generation methods (Change 131)

-        Design code references have been added for all symbols from NBCC and the Commentary.

-        Combined pressure coefficient and gust factor no longer given for I-15 procedure, replaced by separate definitions of Cp and Cg factors.

-        Separate definitions for internal and external factors

-        Explanations of load Magnitude and Start and End given

-        Separate table header for C&C load items which differ from MWFRS items. They are no longer indicated by asterisks and a difficult-to-spot note.

-        Now indicates that velocity pressure is one in fifty year pressure.

C:  Load Distribution

1. Accumulation of Direct Shearline Force for Seismic Design (Bug 2630)

Starting with Shearwalls version 8, when a seismic direct shearline force was applied to a shearline, the program did not include that force in the rigid diaphragm design shear. The direct forces did show up in both plan view and elevation view, but not accumulated with forces on the line from the generated loads, so the numbers overlap. This has been corrected and the seismic direct shearline forces are once again included in the design shear force.

2. Distribution Method for Seismic Direct Shear Forces (Bug 2632)

Starting with version 8.1 the Distribution Method control in the Load Create and Load Edit dialog boxes was disabled and showing Both when entering or editing manually entered seismic direct shear forces. This has been corrected and you can again distinguish between rigid and flexible distribution methods when adding a direct shearline force.

 

Shearwalls 8.2 – Design Office 8 Service Release 2 – January 9, 2013

The links below lead to descriptions of the changes made to WoodWorks Shearwalls for Version 8.2 

A: Force Distribution and Engineering Design. 1

1. Elevated Dead Load Magnitude and Reduced Jhd Factor (Bug 2565) 1

2. Non-wall Dead Loads Treated as Wall Dead Loads (Bug 2571) 1

3. Nail Slip Deflection of Unloaded Gypsum Wallboard (Bug 2577) 1

4. OSB Shear Defection Values for Deflection Design (Bug 2582) 1

5. Segment Shear Value in Deflection Table when Both Sides Same (Bug 2584) 1

6. Shear Deflection for Custom Sheathing Thicknesses (Bug 2585) 1

7. Nonsense Hold-down Values at Gable End of Monoslope Roof (Bug 2509) 1

8. Crash for Walls Spanning Multiple Blocks at Gable End (Bug 2510) 1

9. Torsional Sensitivity Seismic Irregularity Detection (Bug 2523) 1

10. Irregularity Message Typo (Change 128) 1

B: Load Generation. 1

1. Base Shear due to Manual Building Masses on North-South Lines (Bug 2518) 1

2. External Pressure Coefficients for Wall Loads (Bug 2595) 1

3. External Pressure Coefficient for Leeward Roofs (Bug 2596) 1

11. Low Rise Wind Loads Due to Note 8 for Positive CpCg Coefficients (Bug 2550)* corrected for Canadian references and terminology. 1

4. MWF Wind Loads All-heights Coefficients in Log File (Bug 2501) 1

5. All-heights Co-efficients for Walls Extending Between Blocks (Bug 2473) 1

C: Data Input 1

1. Standard Wall Relative Rigidity (Bug 2522) 1

2. Bolt Diameter Input in Hold-down Database for Decimal Imperial Formatting (Bug 2517) 1

3. Hold-down Database Message (Change 116) 1

4. Apply Load Change Message (Change 119) 1

5. Seismic Load Generation Input Typos (Change 121) 1

6. Arrange Icons Menu Item (Change 129) 1

D: Text Output 1

1. Wind Load Importance Factor for Deflection (Bug 2576) 1

2. Log file for Wind Generation (Changes 115,124.142) 1

3. Log File output of Area Load Magnitude (Bug 2483) 1

4. Precision of Design Shear Values in Shear Results Output (Bug 2495) 1

5. ASD Typo in Hold-down Displacement Table (Change 118) 1

6. Bending Term in Deflection Table Legend (Change 127) 1

E: General Program operation. 1

1. Failure to Open a Project File (Bug 2088) 1

2. Back-up Files (Change 123, Feature 203) 1

A:  Force Distribution and Engineering Design

1. Elevated Dead Load Magnitude and Reduced Jhd Factor (Bug 2565)

Starting with version 8.11, dead loads over openings did not accumulate properly, creating two sets of overlapping loads in load view over openings, with a load used for hold-down creation and Jhd calculation that is much too large. Therefore, there is too heavy a countervailing dead force at hold-down locations, and the Jhd factors that are calculated via 9.4.5.2,3 are significantly too small, as Jhd is directly related to hold-down force P. Both of these are non-conservative errors, and have been corrected.

2. Non-wall Dead Loads Treated as Wall Dead Loads (Bug 2571)

Entering a dead wall load caused subsequently entered dead loads to be treated as dead wall loads, even if the checkbox for wall dead loads is not checked. As a result, the uplift restraining force P in 9.4.5.3 for hold-down factor Jhd did not include these loads, resulting in a smaller than expected P and larger than expected Jhd, a non-conservative error. This equation is used wherever an anchorage exists above a hold-down. This problem has been corrected.

3. Nail Slip Deflection of Unloaded Gypsum Wallboard (Bug 2577)

When the constant nail slip deflection for gypsum wallboard (GWB) is so much greater than the deflection for the wood side that it draws no load, the program was still assigning the constant nail slip deflection to GWB. As a result, the deflection of the shearline was much greater than it should be, and it’s stiffness is much less, causing it to draw less loading under rigid diaphragm distribution or when loads are distributed to dissimilar materials along a shearline. This happened most often under low loading conditions, and has been corrected.

4. OSB Shear Defection Values for Deflection Design (Bug 2582)

For the OSB construction sheathing thicknesses other than the smallest for each panel marking, the program used zero for shear deflection rather than the actual shear deflection. The program now gives the correct shear deflection in this case.

5. Segment Shear Value in Deflection Table when Both Sides Same (Bug 2584)

When there is the same sheathing on both sides of the shear wall, the v value reported in the deflection table is the shear going into just one of the sides, so it is in fact ½ the total shear applied to the segment.  The resulting deflections calculated are correct; however the program was showing a misleading shear value. The program now shows the total shear going into the segment in this case.

6. Shear Deflection for Custom Sheathing Thicknesses (Bug 2585)

If you type in a sheathing thickness rather than a standard one, the shear deflection was set to zero. This has been corrected and the program now uses the deflection for the next smallest sheathing.

7. Nonsense Hold-down Values at Gable End of Monoslope Roof (Bug 2509)

When there is a monoslope roof, the hold-down calculations at the gable end yielded nonsense values indicative of a divide-by-zero situation. These hold-down forces appeared in all output and were used in the design of hold-downs at these locations. This has been corrected.

8. Crash for Walls Spanning Multiple Blocks at Gable End (Bug 2510)

When all the following criteria are met

-         A wall is directly under a gable end

-         The wall spans more than 1 block

-         The last block in the block list doesn't have any sides that are collinear with the wall

The program crashed when performing load and force distribution. This occurred regardless of whether there are actually any loads on the structure. This sometimes happened when loading a file and the program proceeds to the load view stage.

9. Torsional Sensitivity Seismic Irregularity Detection (Bug 2523)

The torsional sensitivity irregularity for rigid seismic design (NBCC 2010 Table 4.1.8.6 Irregularity Type 7), was not being detected when it should have been. The program was mistakenly comparing the deflections due to positive and negative torsion for each outer edge shearline.  It should have been comparing the deflections of the opposite outer edge shearlines, and is now doing so.

The incorrect calculations would rarely result in a torsional irregularity being detected.

10. Irregularity Message Typo (Change 128)

The message that appears when seismic irregularities 4-6 are detected has been corrected to refer to APEGBC instead of APERGBC.

B:  Load Generation

1. Base Shear due to Manual Building Masses on North-South Lines (Bug 2518)

When a building mass is manually added to a North-south shearline, the seismic load from the resulting mass did not contribute to base shear on the structure, creating lower-than-expected forces distributed to the building levels.  However, the seismic load from the building mass is created, using the base shear computed without the contribution of that load. Furthermore, when any seismic load is entered manually, it is not included in the base shear to be distributed to the rest of the building. This is not incorrect, but has been made more evident to the user via a note beneath the seismic information table and in the log file.

2. External Pressure Coefficients for Wall Loads (Bug 2595)

Starting with version 8.11 of the program, instead of the expressions for external pressure coefficient, Cp, based on  height to depth ratio from NBCC 2010 Figure I-15 , the program always used the value of 0.27 in the range  0.25 < H/D < 1.0, resulting in loading that was less than half of what it should be. This has been corrected and the program uses 0.27( H/D + 2.0) for windward walls and -0.27( H/D + 0.88) for leeward walls.

Note that for buildings in these ranges are ordinarily designed using the low-rise method, I-7, but Shearwalls does not use this method for multi-block structures, and it is likely not be used for flat roofs, so this problem is likely to have occurred for these types of structures.

3. External Pressure Coefficient for Leeward Roofs (Bug 2596)

Because NBCC Figure I-15 is only applicable to flat-roofed buildings, a decision was made to apply the external pressure coefficients for walls, Cp, to the vertical projection of roof panels. However, the coefficient applied to leeward roofs was not following the wall coefficient calculation based on height to depth ratio. Instead it was using the worst case leeward wall coefficient, -0.5, resulting in heavier-than expected loading for h/d ratios less than 1. This has been corrected and the program is applying the coefficients 0.27( H/D) for 0.25 < H/D < 1.0 and 0.3 for h/d < .25.  Note that for buildings in these ranges are ordinarily designed using the low-rise method, I-7, but Shearwalls does not use this method for multi-block structures, and it is likely not be used for flat roofs, so this problem is likely to have occurred for these types of structures.

11. Low Rise Wind Loads Due to Note 8 for Positive CpCg Coefficients (Bug 2550)* corrected for Canadian references and terminology

Low-rise wind loads due to Note 8 of Structural Commentary Figure I-7, that specifies zone 3 loads  on a portion of a zone 2 windward roof, were being generated for high angles with positive Zone 2 co-efficient CpCg when they should be limited to low angles with negative CpCg,. The resulting zone 3 loads have a negative coefficient that combined with the loads with a positive zone 2 coefficient to reduce the total load on the roof, creating non-conservative wind loading. This has been corrected.

4. MWF Wind Loads All-heights Coefficients in Log File (Bug 2501)

The CpCg coefficient shown in the log file for main wind force resisting system loads for the all-heights wind generation was divided by the Ce factor when it should not have been. This has been corrected.

5. All-heights Co-efficients for Walls Extending Between Blocks (Bug 2473)

When a building is made from multiple intersecting blocks, the program creates two walls along one of the sides of an "L", but only one wall along the side of another. The two walls are assigned to different blocks for wind load creation, but one the one wall extending between two blocks and until now was assigned to only one block for wind load generation. When this occurs, you have no way of splitting the long wall up and manually assigning different blocks to the separate walls. This also occurs when you manually joined walls from separate blocks.

This could create incorrect wind loads for blocks with radically different height-to-width ratios, for example, that a wall extends from a one-storey block to high one with several stories. It has been corrected and the program internally splits the wall up and assigns the co-efficients from the correct blocks to the walls.

Refer to an explanation in the Help files, under Canadian wind load procedures, for a picture and more details.

C:  Data Input

Note that the version of this document originally included with Shearwalls 8.2 mistakenly included two changes that have since been removed: Apply Load Change Message (Change 119) and Seismic Load Generation Input Typos (Change 121).

1. Standard Wall Relative Rigidity (Bug 2522)

The "Relative Rigidity" input for Standard walls was not reflected in the individual walls’ relative rigidity. The program now considers relative rigidity field when comparing walls to see if they match standard walls.

2. Bolt Diameter Input in Hold-down Database for Decimal Imperial Formatting (Bug 2517)

When the Thickness Imperial formatting setting is set to Decimal, then the list of bolt shaft diameters in the Hold-down database input shows nonsensical values like “1/1”.  If you select one of these, or attempt to enter a value like .45, the program converted it to 0, 1, or a nonsense value the next time the box is opened. This has been corrected.

3. Hold-down Database Message (Change 116)

The message indicating that one hold-down had to be completed before another selection had a grammar error.

4. Apply Load Change Message (Change 119)

After first entering the Load Input view, changing loads prompted you to apply changes when none had been made. This has been corrected

5. Seismic Load Generation Input Typos (Change 121)

The spelling of Self-weights has been corrected from Self Weights. The “Generate building masses first…" section title has been extended to fit the ellipses.

6. Arrange Icons Menu Item (Change 129)

The Arrange Icons menu item was removed from the Windows menu as it was obsolete and had no function. 

D:  Text Output

1. Wind Load Importance Factor for Deflection (Bug 2576)

The program now indicates in the legend to the deflection table that the shearline forces are multiplied by the ratio of the serviceability to strength importance factors, or in the case of Normal importance, 0.75. For this case, the shearline force that appears in the table is a factor of 0.75/1.4 less than the strength force (1.4 being the wind load factor.) Since the legend did not indicate that it is factored, some users expected it to be just 1/1.4 times the shearwall design force.

2. Log file for Wind Generation (Changes 115,124.142)

The output of wind loads for the log file has been updated as follows:

-         NBCC references have been added to each equation.

-         The Iw in the Site information has been expanded to Importance factor: Iw. 

-         Spaces have been added to pressure equations to make them more readable.

-         For Fig I-15 generation method the following changes have been made: 

-       The columns and legend entries for the low-rise values windward corner, Case A or B, and slope have been removed;

-       The combined CgCp column has been separated into individual columns for Cp and Cg, with corresponding changes to the legend. For C&C loads, the combined CgCp value is output between the Cg and Cp columns.

3. Log File output of Area Load Magnitude (Bug 2483)

The magnitude of C&C loads and MWFRS loads created as area loads showed up as zero for metric output and a very small number like 0.1 for imperial output.  They are now shown as they appear on the screen, with numbers like 0.455 kN/m2 or 24.3 psi. 

A line has been added below the table saying “Magnitudes are area loads for C&C and line loads for MWFRS loads” or “Magnitudes are area loads”, depending on how the loads were generated.

4. Precision of Design Shear Values in Shear Results Output (Bug 2495)

Starting with version 8, the design shear values in pounds per linear foot, Fv/L, appear in the shear results table as whole numbers. Previously they had 0.1 plf accuracy, which has been restored.

5. ASD Typo in Hold-down Displacement Table (Change 118)

In the hold-down displacement table, it now says ASD, not ADS, when referring to load combinations

6. Bending Term in Deflection Table Legend (Change 127)

In the legend for to the deflection table, the numerator to the expression for the bending term started with a 2 when it should have been a 3. The correct equation was used for design; this is just an output typo.

E:  General Program operation

Note that the version of this document originally included with Shearwalls 8.2 mistakenly included the change Getting Started Steps (Change 116) that has since been removed.

1. Failure to Open a Project File (Bug 2088)

Periodically the program issued an "Unexpected file format" or "WoodWorks has stopped working message" when opening a project file.  When this occurred the file could not be used and if there was no backup file, then the project had to be reconstructed. This has been corrected.

2. Back-up Files (Change 123, Feature 203)

The program now saves two files to the Windows 7 folder C:\Users\[username]\AppData\Local\WoodWorks\CWC\Canada\8 – BackupPre.wsw and BackupPost.wsw. The first of these saves a project file immediately before design or load generation, the second saves the file after design or load generation.

These files are accessed in the following situations:

-        if an unsaved file is lost after a successful design or load generation is made, for example by an automatic system reboot. Either file can be used for this.

-       The file BackupPre is used to record the state of the program before design/generation, so that if a fatal error occurs during one of these processes, you will have a file to send WoodWorks technical support for diagnosis. In most cases, this file cannot be used to continue work, as the error will likely occur again on the next design.

-       The file BackupPost is used to continue work if an error occurs during design or load generation, or at any other time. It will return you the state you were in when the last successful design or generation occurred. Then you can try to remake the changes you made to your structure, and it is possible the error will not re-occur. If it does, contact Woodworks Technical support and they will try to diagnose the problem and find a work-around. 

The folder that these files are saved to in Windows XP is C:\Documents and Settings\[username]\Local Settings\Application Data\WoodWorks\CWC\Canada\8\.  

 

Shearwalls 8.11 – Design Office 8 Service Release 1 – May 22, 2012

Some of the changes listed below first appeared in Shearwalls 8.1, which was released as an Educational version only. These changes are indicated by Version 8.1 in the next to the change reference. The links below lead to descriptions of the changes.

A: Engineering Design. 1

1. Crash on Design with Non-shearwalls (Bug 2395 – Version 8.1) 1

2. Wall Height at Gable Ends for Hold-down Force Calculation (Bug 2465) 1

3. Creation of Wall Groups due to Hold-down Data (Bug 2323) 1

4. Negative Jhd Factor for Hold-downs on All Walls (Bug 2445) 1

5. Inclusion of Gypsum Capacity for Tall Walls (Bug 2447) 1

6. Extraneous Message when Running a Design (Bug 2439) 1

7. Irregularity Check Warning (Change 110 – Version 8.1) 1

B: Loads and Load Generation. 1

1. Wind Uplift Load Directionality (Feature 115) 1

2. Building Mass Generation for Separate Floors (Bug 2386 – Version 8.1) 1

3. Low Rise Wind Generation for Multiple Blocks that are Deleted (Bug 2430) 1

4. All-heights Wind Load Coefficients. 1

5. Structure Height-to-width Ratio. 1

6. Multi-block All-heights Warning Message (Change 113) 1

7. Precision of Velocity Pressure q in Log File (Change 114) 1

8. Log File output of Area Load Magnitude (Bug 2484) 1

C: Data Input and Program Operation. 1

1. Standard Walls. 1

2. Stud Width and Thickness. 1

3. Legend Checkbox in Options Settings (Bug 2398– Version 8.1) 1

4. Hold-down Settings Dimensional Units (Bug 2468) 1

5. Spin Controls for Building Levels in Generate Loads Input View (Bug 2387 - Version 8.1) 1

6. Deflection Analysis Setting Update (Bug 2327) 1

7. Version Number in Program Name (Change 111) 1

8. Streamline Network Version Setup (Design Office Feature 8) 1

D: Output and Graphics. 1

1. Interior Non-shearwall Material Information in Elevation View (Bug 2352) 1

2. Floor Joist Length in Elevation View (Bug 2383) 1

3. Overlapping Hold-down Forces at Vertical Elements in Elevation View (Bug 2389) 1

4. Overlap of Structure and Legend/Materials In Elevation View (Bug 2405– Version 8.1) 1

5. Wall Name in Shearline, Wall and Opening Dimension Table (Bug 2420) 1

 

A:  Engineering Design

1. Crash on Design with Non-shearwalls (Bug 2395 – Version 8.1)

In some cases, the program crashed when designing a structure that has a non-shearwall and deflection design is enabled. This has been corrected.

2. Wall Height at Gable Ends for Hold-down Force Calculation (Bug 2465)

In order to include the portion of an end wall that is beneath a gable end as part of a shearwall, for the purpose of hold-down force calculations, the program now calculates the wall height at a gable end as being the distance from the base of the wall to the height of the sloping roof at the end of a wall segment.

The average of the heights at both ends of the segment under a gable end is used as the moment arm h in the hold-down force calculation R = vh, where R is the hold-down force and v is the shear per unit foot directed horizontally. Previously the height of the upper level was used as the wall height. Refer to the Shearwalls Help topic Hold-down Forces for further explanation.

3. Creation of Wall Groups due to Hold-down Data (Bug 2323)

The program created wall design groups based on hold-down information such as "number of brackets”, hold-down type, and number of end studs. It no longer does so for the following reasons:

-        The Sheathing and Framing Materials output does not show these values, so there was no evident difference between wall groups.

-        These parameters do not affect design of the wall, just deflection

-        These parameters differ from other wall group parameters in that they can be different for different walls on the line when “dissimilar materials” are not allowed. Therefore a line would have two groups designed for it, and only one of these was used for design.

-         The default hold-down configuration is to have single bracket on first level and double on others, so by default wall 2 wall groups were made even if all materials are the same.

4. Negative Jhd Factor for Hold-downs on All Walls (Bug 2445)

For a particular project, two walls on one level were not designed, so that the program showed vertical elements rather than wall ends at the hold-down locations, the hold-downs were not designed, and a spurious message regarding a negative Jhd appeared.  Upon examination, this problem was caused by incorrect conversion of joist spacing when toggling between metric and imperial modes. This has been corrected.

5. Inclusion of Gypsum Capacity for Tall Walls (Bug 2447)

When using imperial units, if the height of a wall was greater than > 3.6 m with gypsum sheathing, the capacity of the wall was not zero as it should be according to CSA O86 Table 9.5.4 note 2. When using metric units, the capacity was zero as it should be. This has been corrected.

6. Extraneous Message when Running a Design (Bug 2439)

In some rare instances, when running a design you get an inaccurate message saying that due to a change in the structure, the last design is no longer valid, and asking you to design again. If you choose to design again, the design proceeds without a problem. This problem has been corrected.

7. Irregularity Check Warning (Change 110 – Version 8.1)

The NBCC reference in the Type 4 - In-Plane Stiffness irregularity check warning message has been updated to refer to sentence 4) of 4.1.8.15 instead of sentence 6). This message is output when the lower storey within a vertical discontinuity has a lower capacity than the storey above.  Also, the spelling mistake in the word Stiffness has been corrected.

B:  Loads and Load Generation

1. Wind Uplift Load Directionality (Feature 115)

The program now allows you to specify the direction for wind uplift loads, that is, the lateral direction of wind force with which the uplift load is associated. Therefore you can enter uplift loads that correspond to the uplift coefficients for the windward and the leeward surfaces in NBCC Figure I-7 for low rise loads and Figure I-15 for all heights. Previously the one wind uplift load applied to a surface would be used for both the windward and the leeward cases. This involved the following program changes:

a) Input

The Wind direction input is now enabled and allows you to choose either direction or Both, similar to a Wind shear load.

b)  Graphics

In the Plan View and Elevation View, the wind uplift force is only drawn if the direction of the uplift force matches the direction of load direction selected in the Show menu.

c) Hold-downs

Different uplift forces are used to create combined hold-downs at the same location for different force directions. These appear in the Hold-down Design table.

d) Output

A Direction column was added to the Uplift Loads table,

2. Building Mass Generation for Separate Floors (Bug 2386 – Version 8.1)

When self-weights were entered in stages for several levels of the structure, and building masses and loads generated at each stage, the loads due to the lower portion of the wall mass from the storey above were not included in the calculation if the loads were generated from top to bottom. Similarly, the loads due to the upper portion of the wall mass from the storey below were not included twice in the calculation if the loads were generated from bottom to top.

Furthermore, the calculation of total building mass used only the masses from floors that had already been generated, leading to a different result than if the loads had been generated all at once.

These problems lead to significantly non-conservative loading when the loads are generated in stages, particularly when it is done from top to bottom of the structure.

They have been corrected and the program now generates the correct seismic loads when building masses are generated in stages. Note that the seismic loads that are generated for a particular level after the entire structure is complete will be different than those at an intermediate stage, because of the difference in total building mass.  The loads generated at the intermediate stages should not be used for design.

3. Low Rise Wind Generation for Multiple Blocks that are Deleted (Bug 2430)

When walls were created using multiple blocks, then all but one of the roof blocks are deleted, the program considered it a single block building when deciding whether low-rise wind loads were allowed. The program used the walls created from only one of the original constituent blocks to determine the height to width ratio, and disallowed buildings that should be allowed. If the one block used had an allowable h/w ratio, then the program generated wind loads on only the walls on that block, and not on the rest of the building. Now, if multiple blocks are used to create the walls, wind loads cannot be generated for low-rise load design, and you are alerted with a message.

4. All-heights Wind Load Coefficients

The following changes apply to the implementation of the NBCC Structural Commentary Figure I-15 method for “high-rise” structures, that Shearwalls uses on all structures for which the low-rise method is not permissible. 

a) All-heights Pressure Coefficients Cp for H/D < 1  (Bug 2469)

The program now applies the wall pressure co-efficients Cp given in Figure I-15 when the height-to-depth ratio is less than 1.0. Previously it was using the maximum values, that is, those for H/D > 1 regardless of the dimensions of the building. This created conservative loading by as much as 33% for windward walls and 66% for leeward walls. The “D” used is the depth of the building block that the wall or roof panel was part of when the walls or roofs were originally created. The H used is the eave height for walls and the ridge height for roofs.

Refer to 5b) below, for the depth used for irregular structures.

b) Interior Zone Local C&C Coefficients (Bug 2480)

The program now implements the local coefficients +- 0.9 for component and cladding (C&C) loads on windward surfaces. These coefficients apply to sheathing and nailing design, as they are intended for components roughly the size of a window according to Commentary I-29. Previously the program was using the coefficient -1.0, from the 1995 NBCC.

c) End Zone Local C&C Coefficient (Bug 2480)

The program now implements the local coefficients -1.2 for C&C loads on the end zones of windward surfaces. These coefficients apply to nailing design, as they are suction forces.  Previously the program was not using separate end zone wind pressures for nail withdrawal, or showing them in the plan or elevation view.

d) CpCg Value for C&C Loads in Log File (Bug 2480)

The combined pressure and gust CpCg coefficient shown in the log file for all-heights C&C loads for the all-heights method did not correspond to the Cp coefficient multiplied by the Cg factor; instead included the Ce factor as well. This has been corrected.

e) Ce Value for C&C Loads in Log File (Bug 2480)

The exposure factor Ce in the log file for all-heights C&C loads was always shown as 1.0. The correct factor now appears.

5. Structure Height-to-width Ratio

a) Building Width for Low-rise Restriction (Change 112, Bug 2466)

When determining the height-to-width ratio of the structure for use in the low-rise load restriction in NBCC Structural Commentary I-26, that is, height/ width < 1, the smallest of the two plan dimensions of the storey with the largest such dimension is now used as the width. Previously the smallest plan dimension of the smallest storey was used, leading to situations whereby this ratio might be determined by a small penthouse. Judgement must now be exercised in using this method for a structure that has an extensive one-storey base with a narrow multi-storey tower above.

b) Building Depth for All-heights Cp (Change 112, Bug 2466)

In determining H/D for Commentary Figure 1-15, the program uses the storey with the largest plan dimension.  Note 1 to Figure 1-15 says to use the dimension of the building at the base, which in almost all cases will be the largest storey.

c) Application of All-heights Restriction (Bug 2432)

When generating wind loads using NBCC Commentaries I-15 all-heights design procedure, if the structure has a height-to-width ratio greater than 4, the wind loads were generated even though NBCC 4.1.7.2 states that dynamic analysis is needed, so that the methods currently in Shearwalls are not applicable. (Dynamic analysis was not implemented due to the rarity of such buildings that also adhere to height restrictions for wooden buildings.)  Now, an error message is displayed, and the wind loads are not generated for height to width rations greater than 4.

d) Building Width for All-heights Restriction (Bug 2466)

When determining the height-to-width ratio of structures with unevenly sized storeys for the purposes of the I-15 all heights restriction, the program now uses the procedure given in 4.1.7.(3), that is, w = ∑hi wi / ∑hi , where hi = height above grade to level i; and wi = width at height hi .

e) All-heights vs. Low Rise Building Width

Note that the building width definition in 4.1.7.2 (3) when considering the applicability of dynamic analysis to all buildings is not used for low-rise height-to-width ratios because the NBCC Structural commentaries in Figure 1-1 assign two separate symbols to these dimensions, w, and Ds, respectively, and they have different descriptors – the minimum building width in each wind direction, and the smallest plan dimension in each direction.  

6. Multi-block All-heights Warning Message (Change 113)

A warning message has been added for the case that the NBCC Commentaries I-15 all-heights design procedure is used with multi-block structures, explaining that the program is for buildings with rectangular plan.

7. Precision of Velocity Pressure q in Log File (Change 114)

In the log file, the precision of the velocity pressure (q) output in kPa units has been increased from 1 to 3 digits.  Velocity pressures are published to two digits precision, so the program was rounding the input precision. Three digits accommodates users who interpolate between locations.

8. Log File output of Area Load Magnitude (Bug 2484)

The magnitude of C&C loads and MWFRS loads created as area loads appeared in the log file as zero for metric output and a very small number like 0.1 for imperial output.  They are now shown as they appear on the screen, with numbers like 0.455 kN/m2 or 24.3 psi. A line has been added in the output saying “Magnitudes are area loads for C&C and line loads for MWFRS loads” or “Magnitudes are area loads”, depending on how the loads were generated.

C:  Data Input and Program Operation

1. Standard Walls

The following problems with the operation of the Standard Wall input were introduced with Version 8 of the program, unless otherwise noted: 

a) Saving Newly Added Standard Walls (Bug 2365– Version 8.1)

When adding a new Standard Wall you could not save the new standard wall unless you had selected an existing standard wall as the basis for the new wall. If you had selected a standard wall as a basis, the material, species and grade fields are not initialized and must be edited in the Edit Standard Walls view before exiting the view. If this is not done you would lose any standard walls that you had created in any session and Shearwalls reverts to using the original set of standard walls.

These problems have corrected.

b) Non-blank Fields when Adding New Standard Wall (Bug 2367– Version 8.1)

Originally, when creating a new standard wall, the program would blank out all material input fields, forcing the user to choose each one in turn. After choosing one, it would only trigger the selection of another one if there was only one choice for that input.

This functionality became successively degraded with each release, and an increasing number of fields became either non-blank from the start, or become selected when another controlling field is selected. Other fields, however, remain blank, creating an inconsistent look and behaviour.

All fields now remain blank, if there is more than one choice, until you select each of them in turn.

c) Standard Wall Identification (Bug 2418)

In Wall Input view, the program did not always identify walls that are created identically to an existing standard wall as being that standard wall, because of inaccuracies concerning the stud thickness and depth. For example, this would occur when the width or depth were changed, then changed back to those for the original standard wall. This has been corrected.

d) Standard Wall Default Setting (Feature 139)

Because the default standard wall selected in the Default Settings applies only to the walls created from the blocks when first entering Wall Input view, the name of the Standard Wall data group box has been changed to Standard wall for exterior footprint.  A note has been placed in the box explaining that new interior walls depend on what is selected in Wall Input view.

2. Stud Width and Thickness

The following problems with the new inputs for stud thickness and width in Wall Input view were corrected:

a) Conversion of Custom Stud Width and Thickness (Bug 2410)

When you entered your own width or thickness (rather than selecting a value) this number was divided by 25.4 before being used in design, and the smaller value appeared when you entered the view again. This resulted in very large deflections due to bending, and correspondingly low wall stiffnesses. It could also skew the distribution of loads to shearlines and within a line in a way that could be conservative or non-conservative for shear wall design. The unit conversion causing this problem has been corrected.

b) Stud Thickness and Depth Unit Label (Bug 2415)

While in Wall Input view, if you changed from imperial units to metric units or visa-versa, then the unit label of the stud thickness and depth were displayed in the original units, not the units switched to. It would remain that way until any other operation was done in this view. The correct units now appear in all circumstances.

3. Legend Checkbox in Options Settings (Bug 2398– Version 8.1)

The following issues with the operation of the Display Legend item in the Options Settings have been corrected.

Control of Material Specification

Turning this option off also controlled the sheathing and framing materials as well as the legend in Elevation View, even though there are separate options the material specification. Now it controls only the legend. 

a) Plan View

A legend option has been added to control the display of the legend in Plan View.

b) Position of Legend Checkbox

The legend option no longer appears between the similar options sheathing and framing, it appears below them.

4. Hold-down Settings Dimensional Units (Bug 2468)

a) Retention of Precision

The values input into the Hold-down Settings box could lose precision when updating after the following operations

-        After being saved as a default for new files

-        Being converted between imperial and metric

-        In some cases, upon re-entering hold-down settings view

-        On the case of the over-rides, immediately after entering the data

These problems have been corrected, and in general values appear to 1/10 of a millimetre and 1/1000 of an inch, however the program will show even millimetre amounts without the decimal, and will remove all but one trailing zero after the decimal place for inches. If more precise values are entered, they will be retained internally, but will be replaced by the rounded value if view is re-entered and another value is modified. 

b) Bolt Hole Tolerance

In metric units, the default bolt hole tolerance would sometimes appear as 0.0625 mm, that is 1/16th of a millimetre. It is meant to be the metric equivalent of 1/16” . This has been corrected. 

5.  Spin Controls for Building Levels in Generate Loads Input View (Bug 2387 - Version 8.1)

The spin controls beside the Building Level inputs in the Generate Loads input form went missing, so that you had to type in a value instead of scrolling to it. They have been restored.

6. Deflection Analysis Setting Update (Bug 2327)

In Design Settings, the default values of the Shearwalls Rigidity options were not being reset when the Include deflection analysis checkbox was reselected. Now, if you choose to do deflection analysis, Use shearwall deflection to calculate rigidity and Distribute forces to wall segments based on rigidity are automatically selected.

7. Version Number in Program Name (Change 111)

Shearwalls now has the version number in the name of the program that appears in the program title bar, and over icons that appear in the start menu. This enables you to quickly identify the version of the program you are running.

8. Streamline Network Version Setup (Design Office Feature 8)

The procedure to set up multiple users running the program from a network server has been streamlined, as follows:

a) Copying of Shearwalls.ini file.

Previously, you had to manually copy a version of the Shearwalls.ini file to all the client machines. The program now does this automatically. 

It is still necessary to modify the Sizer.ini in the server to indicate it is a network version and give the location of the program on the server. A new step is required, to copy the files from the Program Data area of the server for All Users to the corresponding folder in the Program Files area of the server. In other words, the Shearwalls.ini file on the server will be found in one of the following locations

Windows 7 - C:\ProgramData\WoodWorks\CWC\Canada\8\

Windows XP - C:\Documents and Settings\All Users\Application Data\WoodWorks\CWC\Canada\8\

After modification, it has to be copied (not only moved) to the following location, if the default installation was selected:

C:\Program Files (x86)\Woodworks\Cdn\Sizer\

The advantage of this approach is that the file has to be copied only once, and within one machine, rather than distributed to several machines.

b) Modification of Database.ini File 

With the introduction of new locations for database and setting files with Version 8, the network installation required you to modify the file Database.ini by indicating it was a network installation. This is no longer necessary.

c) Instructions in “Read Me” File

The instructions in the Shearwalls Read Me file have been modified to explain the new procedure. In addition, the following corrections have been made:

-      The instructions regarding key code security instruct you to contact WoodWorks sales, rather than using a key code that is delivered with the software.

-      Instructions were given for those users who wish to modify the database files on their local machine using Database Editor on the server. These have been removed, as this procedure is not possible.

 

D:  Output and Graphics

1. Interior Non-shearwall Material Information in Elevation View (Bug 2352)

For interior non-shearwalls, or for exterior non-shearwalls for seismic-only design, known material input was showing up as Unknown in the elevation view material output. Now, if material input is defined for an interior or seismic non-shearwall, then it shows up in the material information.  If the inputs are left as unknown, they appear as unknown as there is no design for interior or seismic non-shearwalls.

Note that if shearlines are not restricted to All walls the same and there is more than one non-shearwall on a shearline only the material information for the southernmost or westernmost non-shearwall is shown.

2. Floor Joist Length in Elevation View (Bug 2383)

In Elevation view, for a multi-storey structure with an upper storey overhanging the storey below, the floor joist of the upper storey did not extend below the overhanging upper storey but only to the end of the storey below. The overhanging portion of the upper storey was therefore without a floor, and vertical elements supporting it had a gap between the top of the element and the supported portion of the building.

The program now draws the floor based on the length of the wall above. Now an end portion of a wall that has no wall above it will no longer show a floor area above it. Such a wall may or may not in reality have a floor area; it could support a sloped roof instead.

This is a display issue only that has no effect on load distribution or design.

3. Overlapping Hold-down Forces at Vertical Elements in Elevation View (Bug 2389)

When compression and tension hold-down forces are distributed downwards by a vertical element, these forces shown in Elevation view at the bottom of the element were drawn overlapping each other. Furthermore, the arrowhead for compression hold-down force in these locations was often drawn within the joist depth rather than outside it as it is usually drawn. This problem has been corrected and the compression and tension forces are shown on either side of the bottom of the vertical element, with a compression arrow of the correct size.

4. Overlap of Structure and Legend/Materials In Elevation View (Bug 2405– Version 8.1)

In Elevation view, lower portions of the wall elevations often overlapped with the legend and materials specification. These problems were more noticeable in Selected Walls mode, and for deep joist depths on the first level being drawn. This has been corrected.

5. Wall Name in Shearline, Wall and Opening Dimension Table (Bug 2420)

In the Shearline, Wall and Opening Dimension table, the wall name had a extraneous, trailing number indicating the building level, for example if there are two walls on a shearline on the first floor they are named A-2-1 and A-1-1. The extra "-1" on the end was removed.

 

Shearwalls 8.1 – Design Office 8 Service Release 1, Educational Version – February 3, 2012

This version of Shearwalls was released as an Educational version only. The changes made for this version are listed in the later Shearwalls 8.11 release, with Version 8.1 indicated in the change name line.

 

 

Shearwalls 8.0 – Design Office 8 - November 14, 2011

This is a major upgrade to the software, containing several extensive new features and many small improvements. The most significant new features are

 

Update to the NBCC 2010 Design Code and CSA 086-09 Standard

Database of Hold-down Connections and Hold-down Design

Shearwall Deflection Analysis for Storey Drift and Stiffness-based Load Distribution

Iterative Load Distribution and Design of Shearwalls

 

Here is an index to all the changes to the program. Click on any of the items to go to the description of the feature or change.

 

A: Update to CSA 086-09 from CSA 086-01. 2

1. CSA O86 Design Standard. 2

2. Deflection of Shearwalls. 2

3. Over-capacity Coefficient 2

4. Hold-downs in High Seismic Zones. 2

5. Seismic Drag Strut Force Factor 2

6. Unblocked Shearwall Limitations. 2

7. Importance Factor 2

8. OSB Type 2 Sheathing. 2

B: Update to NBCC 2010 from NBCC 2005. 2

1. National Building Code of Canada. 2

2. Torsional Sensitivity Irregularity. 2

3. Accidental Torsion for Flexible Diaphragms ( Feature 125) 2

4. Minimum Seismic Base Shear 2

C: Hold-down Connections. 2

1. Hold-down Types and Properties. 2

2. Hold-down Database. 2

3. Hold-down Database Editor 2

4. Hold-down Input 2

5. Hold-down Settings. 2

6. Hold-down Design. 2

7. Output 2

D: Deflection Analysis. 2

1. Deflection Calculations. 2

2. Hold-down Deflection. 2

3. Shear Distribution to Wall Segments Within Shearline. 2

4. Rigid Diaphragm Analysis. 2

5. Story Drift Calculations. 2

6. Output 2

E: Shearwall Design Iterations. 2

1. Previous Versions. 2

2. Structural Iteration for Irregularities. 2

3. Design Iterations Per Level 2

4. Final Design Check. 2

F: Other Engineering Design Issues. 2

1. Shear Strength of Unblocked Shearwall (Bug 2250) 2

2. Gypsum Wall Board for Wet Service Conditions (Bug 2251) 2

3. Segment Output in Seismic Shear Results Table (Bug 2275) 2

4. Gypsum Wallboard Storey Capacity for One Directional Loading (Bug 2273) 2

5. Percent Gypsum Shear for Asymmetric Wind Loads (Bug 2264) 2

G: Load Distribution and Accumulation. 2

1. Bi-Directional Seismic Rigid Diaphragm Analysis (Bug 2282) 2

2. Wind Uplift Loads over Openings (Bug 2132) 2

3. Shearlines with Zero Capacity and Non-zero Shear Force (Bug 2211) 2

4. Full Height Sheathing Output for Excluded Gypsum Walls (Bug 2355) 2

5. Accidental Eccentricity Reference in Log File for  Medium Rise Wind Loads (Bug 2295) 2

6. Low-rise Wind Load Rigid Diaphragm Cases in Log File (Change 91) 2

7. Design Cancel (Change 100) 2

H: Load Generation. 2

1. Maximum Seismic Base Shear Vmax in Log File Output. (Bug 2054) 2

2. Input of T Greater than Maximum (Bugs 2281, 2130) 2

3. Vertical Location of Upper Wall Load (Bug 2107) 2

4. Area Load Tributary Width and Magnitude Reporting (Bug 2108) 2

I: Input and Output 2

1. Menus and Toolbars. 2

2. Input Dialogs. 2

3. Output 2

4. Miscellaneous. 2

J: Installation and System Issues. 2

1. Program Data File Locations (Bug 2265) 2

2. Log File Issues. 2

 

A:  Update to CSA 086-09 from CSA 086-01

1. CSA O86 Design Standard

The program has been updated for the CSA 086-09 Engineering design in wood design standard. The previous version was based on CSA 086-01.

The 086-09 implemented is the 2010 reprint that includes Update No. 1.

These changes are reflected in the program Welcome box, the Building Codes box, and the About Shearwalls box.

2. Deflection of Shearwalls

The program now implements the new shear wall deflection requirements given in 9.7. The details are given in D:  below, Deflection Analysis, with relevant changes also in C: Hold-down Connections .

 

Note that several of the following changes depend on the seismic load generation value IEFaSa(0.2). IE, Fa , and Sa are defined in NBCC 4.1.8.5(1), 4.1.8.11(6), and 4.1.8.4(1), respectively. It is shown above the Seismic Irregularities table.

 

3. Over-capacity Coefficient*

The program checks the over-capacity coefficient from CSA O86 9.8.3.1 for structures three or more storeys in height and when IEFaSa(0.2) is greater than or equal to greater than 0.35, as per 9.8.1.  

The shear capacity and over-capacity ratio of each floor has been added to the Seismic Information table for each floor and direction. The storey shear shown is now the vertically accumulated shear used for shear wall design rather than the single storey shear distributed to each floor during seismic load generation. (The single storey shear can still be found in the log file under seismic load generation.) 

The ratio of overcapacity for level 2 to level 1 is shown at the bottom of the table.  A note below indicates that it is within the acceptable range of 0.9 and 1.2, a warning is issued if it is outside that range. 

*This description modified in March, 2013.

4. Hold-downs in High Seismic Zones

When IEFaSa(0.2) is greater than or equal to greater than 0.35, as per 9.8.1,  seismic hold-down forces based on applied loads are increased 20% as per 9.8.2. The legend under the Hold-down Design table has been revised to reflect this.

a) Capacity vs Applied Load

This factor is not applied if shear wall capacity is used to create hold-down forces, rather than applied loads. However if 1.2 x applied load is greater than shearline capacity, that value is used and a note below the Hold-down design table indicates this.

b) Elevation View

The legend in Elevation view shows the 1.2 factor and 9.8.2 reference when it is applied.

9. Seismic Drag Strut Force Factor

Seismic drag strut forces based on applied loads are increased 20% as per 9.8.6.  Note that this is not contingent on the value of IEFaSa(0.2), as per 9.8.7.3. The legend under the Drag Strut Forces table has been revised to reflect this.

a) Capacity vs Applied Load

This factor is not applied if shear wall capacity is used to create drag strut forces, rather than applied loads. However if 1.2 x applied load is greater than shearline capacity, that value is used and a note below the Drag Strut Forces table indicates this.

b) Elevation View

The legend in Elevation view shows the 1.2 factor and 9.8.6 reference.

10. Unblocked Shear Wall Limitations

a) Maximum Height

The maximum height of an unblocked shear wall has increased from 2.44m to 4.88m, as per the change in 9.4.4.

b) Height-to-width Ratio

The maximum height-to-width ratio for unblocked shear wall has been reduced to 2:1 from 3.5:1, as per the new limitation in 9.4.4.  An item has been added to the Design Settings output echo to show the ratios for blocked and unblocked shear walls (despite the fact that this has been removed from the design settings choices, see Program Operation change 104 below.)

c) Unblocked Vertical Sheathing

When the vertical orientation of sheathing is selected, blocking was disabled and unchecked, but the program treated the wall as blocked because of the assumption that the edges of a 4x8 sheet are supported on the studs and bottom and the top plate. Given the new height requirements, the program now allows you to specify whether vertical sheathing is blocked or unblocked.

11. Importance Factor

The Importance factor for earthquake loads, used in seismic load generation, was changed in 4.2.3.2 from 1.0 to 0.8. However, Shearwalls 7.22 had been using the 0.8 importance factor, based on NBCC 2005  4.1.8.5, so change to the program was made.

12. OSB Type 2 Sheathing

As the CSA O86 no longer lists OSB Type 1 Sheathing, it has been removed as an input choice.  If a file is opened from a previous version that contains OSB Type 1, then the material type of this wall is changed to construction OSB and the grades A, B or C are changed to 2R24, 1R24_2F16 and 2R32_2F16 respectively. If the thickness specified is outside of the range of the valid thicknesses for that marking type then the thickness is set to the smallest thickness for that marking type.

B:  Update to NBCC 2010 from NBCC 2005

1. National Building Code of Canada

The program has been updated for the 2010 National Building Code of Canada (NBCC). The previous version was based on NBCC 2005.

This change is reflected in the program Welcome box, the Building Codes box, and the About Shearwalls box.

2. Torsional Sensitivity Irregularity

The program now detects torsional sensitivity irregularity 7 from Table 4.1.8.6, by determining the ration B in. 4.1.8.11(9). Note that this is not a new design code clause, but implementation was made possible by the deflection analysis added to the program.

a) Torsional Analysis Changes

Previously, for each extreme shearline Shearwalls determined only torsional component for the direction of accidental eccentricity that augmented the direct force on that line. Now the program determines the torsional forces and resulting deflections for each combination of extreme shearline and moment direction, + or -, to determine the δmax values needed.

b) Rigid Diaphragm Analysis Procedure

The program checks whether the rigid diaphragm analysis procedure is allowed according to 4.1.8.11 (10) by checking that the maximum B of all Bx on each level as defined in 4.1.8.11(9) is less than or equal to 1.7, or that IEFaSa(0.2) is less than 0.35.

c) Torsional Irregularity Table

The program now indicates within the table whether each floor and direction has Irregularity 7, and which ones fail because it has the irregularity and IEFaSa(0.2) is greater than 0.35. If it does fail, a note appears below the table saying that rigid diaphragm design results are not valid.  

d) No Deflection Analysis

If you have chosen to disable deflection analysis in the Design Settings, then this check is not performed. The Irregularities table indicates it is detected by the user, not the program, puts n/a in the Irregular and Fails columns, and places a note below the table explaining the reason and what can be done about it.

3. Accidental Torsion for Flexible Diaphragms (Feature 125)

The program now implements NBCC Structural Commentary J 178, which says.

 

Structures with flexible diaphragms are designed so that their loads, including the effects of accidental torsion, are distributed to the vertical elements using the tributary area concept.  Accidental torsion should be taken into account by moving the center of mass by +/- 0.05Dnx and using the largest seismic loads for the design of each vertical element.

 

Note that the 2010 Wood Design Manual (WDM) Example 1, Seismic Design Considerations (p470) includes this force by adding 5% to the total shearline force.

a) Calculation Procedure

Noting that to direct (non-torsional) component of the shearline force should be that determined by tributary area distribution, this can be achieved by setting the rigidities K to the flexible shearline force, seeing that 

 

Fdi = F * Ki / Σ Ki,

 

using the notation in the Log file, F being the total force. In that case, the center if mass CM = centre of rigidity CR, and we are including just the accidental eccentricity ea and not the eccentricity of the structure or loads. We also do not consider the torsional moment J in the other direction, as none of the loads are in the other direction.   The torsional component on each line is then

 

Fti = T * Ki * di / (Jx)

 

where di is the distance of the shearline from the centre of load and

 

Jx = Σ Ki * di 2 ; T = F * ea

 

Shearlines already heavily loaded get higher contributions of accidental torsion, rather than those that are stiffer as in the case of rigid analysis. With seismic analysis, the distribution of load is proportional to the distribution of the mass of building material, which itself is proportional to the “area” that the NBCC commentary is referring to. So with this method, the torsional component is distributed using the tributary area concept as the NBCC mandates.

b) Verification of Calculation Procedure

To show that a simple case of uniform load on a rectangular building is consistent with the WDM example, consider a 20 m wide building with 1 kN/m force the diaphragm.  

F = 20 kN; Fd1 = Fd2 = 10 kN; K1 = K2 = 10 kN; ea = 1 m; di = 10 m; T = 20 kN-m; J = 2000 kN-m2

Ft1 = Ft2 = 20 kN-m x 10 kN x 10m / 2000 kN-m2 = 1kN

= 5% F

c) Log File Output

The title of the entire section of the log file for torsional analysis has been changed from “RIGID DIAPHRAGM ANALYSIS” to “TORSIONAL ANALYSIS” , in recognition that some of the output now pertains to flexible analysis. A section is added at the top of the results called, FLEXIBLE SEISMIC DESIGN. The assumptions given in section a), above, are shown first, then the results are given as they are for rigid diaphragm analysis. The source of the accidental eccentricity is given as NBCC Structural Commentary J 178. 

2. Minimum Seismic Base Shear

Previously, NBCC 4.1.8.11 (b) for minimum seismic base shear V was the base shear based on S(T = 2.0), and applied to all structures. Now, the requirement for walls is shear walls is 4.1.8.11 (a), the minimum shear based on S(T = 4.0). As the program has no input for S(T = 4.0), and elsewhere in the program, we assume periods are not greater than T= 0.5 based on the height of the structure, we have dropped the minimum base shear as not applying to wood structures. You could conceivably enter a large enough period that the minimum is achieved, but that would not represent a realistic structure.

B:  Hold-down Connections

1. Hold-down Types and Properties

a) Hold-down Assembly

The hold-downs in shear walls connect the wall end studs on an upper level to either the corresponding stud on a lower level or anchored to the foundation. Continuous tie rod systems extending over multiple building levels are not included in this version of Shearwalls.

i. Vertical Connection

Hold-downs include either an anchor bolt or threaded rod which connects upper and lower brackets or straps, or a continuous strap extending from upper to lower level.

ii. Horizontal Fasteners

The connection from bracket or strap to the upper and lower studs is made via bolts or nails, however this distinction is not implemented in the program as an overall capacity and displacement is specified for each hold-down, and the strengths and slippages of the components of the hold-down not needed.   

iii. Single or double bracket

Hold-downs are designated as being either single-bracket or double bracket, indicating that the hold-down has a bracket or strap on one floor or both. By default, hold-downs on the ground level are single-bracket, and upper-level hold-downs are double-bracket. The data in the hold-down database are published for one bracket only and are doubled when the hold-down is designated as double bracket in the Shearwalls program.  

iv. Shrinkage Compensating Device

You can designate that the hold-down includes a mechanical device to adjust for the shrinkage of the perpendicular-to-grain wood between the extreme hold-down fasteners, so that such shrinkage is not included in the calculations for shear wall deflection.

b) Displacement and Capacity Sources

 There are three possible sources of vertical hold-down displacement that affects shear wall deflection:

-        anchor bolt elongation,

-        bracket or strap elongation,

-        slippage of horizontal bolts or nails.

Similarly, the capacity of the hold-down takes into account the possible failure in tension of the bracket or strap, the anchor bolt in tension, and the connection of the horizontal fasteners to the wood studs.

The published data are assumed to include all of these sources, except that displacement values include the elongation of the anchor bolt to a maximum length. Elongation of the portion of the anchor bolt greater than that length is analysed separately.

c) Method of Determining Displacement

Hold-downs are designated according to the method we use for determining the vertical displacement under loading, as follows.

i. Displacement at Actual Force

With this method, ratio of the capacity of the hold-down to the maximum capacity is multiplied displacement to give the displacement used for deflection analysis and storey drift. This assumption of linear may not be correct, due to the non-linear effects of fastener slippage. This would yield non-conservative results for storey drift determination. However, the choice also affects load distribution to and within shearlines using stiffness analysis, for which the effect may be conservative or non-conservative.

ii. Displacement at Maximum Capacity

With this method, the published displacement at maximum capacity is used regardless of the shear wall force.  This ensures conservative storey drift calculations. This choice also affects load distribution to and within shearlines using to stiffness analysis, for which the effect may be conservative or non-conservative.

2. Hold-down Database

The program includes a database of standard hold-downs, which you can edit using a database editor incorporated in Shearwalls to update hold-down properties or add new hold-downs

a) Database File

The Database folder of the WoodWorks installation contains a file called Holddowns.mdb, which is a Microsoft Access database of hold-downs used by the Shearwalls program. Shearwalls now includes an editor to modify the database, but it is also possible to modify the file directly via Microsoft Access.

b) Database Structure

The database consists of two tables, a Hold-down table that contains the properties of the hold-down that are relevant to Shearwalls design, and a Displacement table which contains hold-down capacities and displacements corresponding to each combination of minimum stud width and depth. The record in the displacement table contains a reference ID to the hold-down that uses that displacement record.

i. Hold-down Table

The hold-down table contains the following data:

-   Name

-   Whether it includes an anchor bolt

-   Anchor bolt diameter

-   The maximum anchor bolt length for which the published elongation applies

-   Whether for this hold-down, we use displacement at maximum capacity for deflection analysis

-    Whether the hold-down includes a shrinkage compensation device

-   Whether the hold-down is to be used as the default hold-down for new projects in Shearwalls

The meaning of these variables is described more fully in the section on Database Input.

ii. Displacement Table

The hold-down displacement table is needed for hold-downs for which the entire assembly displacement is published. For those hold-downs for which only the bracket or strap elongation is published, then only one displacement record is needed, corresponding to the elongation of the bracket or strap. The displacement of anchor bolt and horizontal fasteners is calculated separately by Shearwalls using the information in the Hold-down table. 

c) Initial Hold-downs

The file in the Shearwalls installation contains a limited number of hold-downs, from the Simpsons Strong-Tie ICC acceptance criteria AC155.

i. Screw mounted Hold-downs

The hold-downs in the initial database that are connected to the upper and lower studs via screws, from the ICC acceptance criteria AC155, are HDU2-SDS2.5, HDU4-SDS2.5, HDU5-SDS2.5, HDU8-SDS2.5, HDU11-SDS2.5, and HDU14-SDS2.5.

ii. Nailed and Bolted Hold-downs

There are no hold-downs in the initial database that are fastened with nails or bolts to the wall studs, however it is possible to add this type of hold-down to the database.  

iii. Strap Hold-downs

There are no hold-downs in the initial database consisting of one continuous strap without an anchor bolt; however it is possible to add this type of hold-down to the database.

d) Single vs Double Bracket Hold-downs

The displacement data in the hold-down database applies to just one bracket or strap of a hold-down. In the program, hold-downs designated as double-bracket have the displacement values doubled, and the maximum anchor bolt length is also doubled.  The capacity data applies to each bracket of the hold-down, and is never doubled.

When creating a hold-down with a continuous strap, you can either

-        enter hold-down data that apply to the elongation of the entire strap and the total number of fasteners, top and bottom, and designate it as single-bracket in Shearwalls

-        enter hold-down data that apply to the elongation of ½ the strap, and designate it as double-bracket in Shearwalls.

3. Hold-down Database Editor

The program includes an editor to view and modify the hold-down data. This editor should be used to update hold-downs for newly published product information from the hold-down manufacturer. It can be also used to add new hold-downs.

a) Access

The database editor is accessed from the following locations:

-        An item in the main menu

-        A button in the Plan View and Design Results window’s toolbars

-        A button in the Hold-down data group in Wall Input and Opening Input views

b) Context sensitive help

Each of the input controls within the database editor has context-sensitive help, explaining its purpose and use. If you click on the question mark in the upper left hand corner of the view, then on the input control a small yellow box appears with the description of the item.

The following are brief descriptions of the input fields within the box; for more details, use the context-sensitive help in the program.

c) Hold-down Selection Controls

The Hold-down selector, New and Delete buttons, and Default… checkbox are used to control the current hold-down being edited. 

i. Hold-down Selector

The hold-down selection dropdown is used to both select the hold-down for viewing and editing properties, to name a new hold-down, or to rename the hold-down by typing over the existing name. It sorts the hold-downs from the database alphabetically.

ii. New

Changes the input mode to refer a new hold-down being created rather than an existing one being edited. 

iii. Delete

Used to delete the currently selected hold-down from the database. Must delete incomplete entries before exiting box.

iv. Default hold-down in Shearwalls

Indicates that this hold-down is the one that is used when new walls are created in Shearwalls.

d) Vertical Bolt ( add’l elongation)

This group pertains to the anchor bolt which connects the upper hold-down bracket or strap to lower bracket or strap, or to the foundation or some other anchoring mechanism.

i. No/with Anchor Bolt

Radio buttons allow you to indicate that the connection does not have an anchor bolt, disabling the other controls and causing the program to dispense with anchor bolt calculations.

ii. Diameter

Shank diameter of anchor bolt, used in tensile strength and elongation calculation, – can select from list or enter custom size.

iii. Max Length for Given Elongation

The length of anchor rod the manufacturer used in tests to determine the displacement or elongation, usually found in a note in the product literature or evaluation reports. Elongation for any excess bolt length is calculated separately by Shearwalls. 

e) Options

There are checkboxes in the view for the following options:

i. Shrinkage Compensating Device

If hold-down a mechanical device to adjust for the shrinkage of the perpendicular-to-grain wood between the extreme hold-down fasteners.

ii. Always use Elongation at Maximum Capacity

A checkbox is used to implement the choices described in Method of Determining Displacement in 1c, above.

f) Displacement

This Data Group allows you to enter different hold-down capacities and/or displacements depending on stud width, thickness, and species group.

i. Elongation/Displacement List box

This box allows you to replicate the tables that appear in the hold-down product literature that have different hold-down capacities and/or displacements for each stud species, thickness and/or width. 

The values apply to only one bracket in a two-bracket hold-down.

ii. All

Entering the word “All” means that the capacity and displacement applies to all values of the thickness or width width of the thickness or depth.

iii. New

Creates a new record corresponding to a line in the table of product information.

iv. Delete

Delete an entire record consisting of one line of the Displacement table. You must delete any incomplete lines before exiting the dialog.

v. Note

For any line in the table, you can enter a note corresponding to the one that appears in the product literature and/or evaluation report to show in the design results any further restrictions on the use of the hold-down, such as on the wood grade or specific gravity.

4. Hold-down Input

a) Hold-downs Data Group

There is similar input for hold-downs at two places in the program – the Wall Input form and Opening Input form. In each place, a hold-down data group contains the following input fields:

i. Hold-down drop-list

For both left and right ends, used to select the hold-down to be used from the list in the database.

ii. Single- or double-bracket

A checkbox indicates that the hold-down is double bracket, that is, the displacement and maximum anchor bolt length entered in the hold-down database applies to only one-half of the assembly, and is doubled for the hold-down assembly used.

iii. Apply to Openings

When this is checked, the inputs apply to all openings on the wall as well as the wall end studs, saving you the effort of updating all the openings manually.

The input of these data applies to all selected walls.

b) Framing Input

The following has been added to the Framing data group of the wall input view:

i. Grade

The grade value is now active for all materials. Previously it was active only for MSR and MEL, for which grade data is needed for the specific gravity, which affects for shearwall capacity.

ii. Thickness and Width

In wall input view, the stud thickness (b dimension) and width ( d dimension)  is input, either by selecting from a list of nominal sections from the database or by typing your own actual value in. The input control behaves in a similar manner to the Width and Depth input in Sizer.

iii. Note that the thickness (b) and width (d) terminology for studs is consistent with product literature, and should not be confused with the width (b) and depth (d) terminology for all members in Sizer.

It is assumed to apply to all studs in the wall, including those at openings and wall ends (which can be built-up from more than one stud.)  

iv. Number of End Studs

Typically wall ends are at least doubled and at times more plies are added to provide tensile or compressive strength or connection strength for the hold-downs. The input of the number of end studs at both left and right end has been added to allow the program to select the hold-down capacity and displacement for the Assembly displacement method (see Error! Reference source not found.). The program does not as yet design the built-up studs themselves.

This input has also been added to the Hold-downs data group (see a) above) in the Opening Input view for the wall studs at the hold-down locations at each side of an opening.

c) Structure Input

New inputs have been added to the Structure Input form that allow for input of parameters that apply to all hold-downs on a single building level.

i. Length Subject to Shrinkage

This input indicates the total vertical extent of perpendicular-to-grain wood members spanned by the hold-down device. Typically the depth of the floor joists plus two top plates on the lower level and one bottom plate on the upper level. For ground level, it depends on the sill plate configuration. Used in hold-down wood shrinkage calculations. 

ii. Anchor bolt length

This indicates the required length of the hold-down anchor bolt, if one exists for a particular hold-down. Typically the length subject to shrinkage plus flooring material thickness. However, in some situations it could be quite different, for example when wood I-joists are used. The I-joist web is included in the anchor bolt length but not in the length subject to shrinkage.

iii. Context sensitive help

Each of these fields have context-sensitive help explaining their use, accessed via the question mark box at the top of the dialog box.

5. Hold-down Settings

A new page has been added to the Settings input for hold-down data that apply to all hold-down locations in the structure. 

a) Context sensitive help

Each of the input controls within this settings page has context-sensitive help, explaining its purpose and use. If you click on the question mark in the upper left hand corner of the view, then on the input control a small yellow box appears with the description of the item.

The following are brief descriptions of the input fields within the box; for more details, use the context-sensitive help in the program.

b) Hold-down forces

A new group box is added to include options affect the generation of hold-down forces from shearline forces on segments.

i. Hold-down Offset

This has been moved to this page from the Default Values page.  In addition, the following capability is added:

If a value is entered that is greater than or equal to ½ a shear wall segment length, the program reverts to the factory default value of 38 mm for that segment. It issues no warning in this case, it is evident only by the placement of the hold-down in elevation view and its position as listed in the Hold-down Design table.

ii. Subtract Offset…in Moment Arm Calculation

A checkbox indicates whether the program subtracts the hold-down offset from the wall length when calculating the overturning moment arm. For the Canadian version, this is disabled and checked, as CSA O86 9.5.6 specifies that the length is to the centre of the end stud(s), implying subtraction of ½ the end stud width.    

iii.    Include Joist Depth…in Moment Arm Calculation

A checkbox indicates whether the program includes the floor depth above the wall in the wall height h when calculating the overturning moment arm. . For the Canadian version, this is disabled and checked, as CSA O86 Figure 9.4.5.2  specifies that you include the joist depth.

c) Displacement da for Deflection – Override Hold-down Properties

The inputs in this data group allow you to replace the vertical hold-down displacement components from with constant values for all hold-downs in the program. They also allow you to specify values for these components if they cannot be calculated or are not available from the hold-down database for a particular hold-down. A warning appears in the output if this situation occurs.

i. Displacement

ii. If box is checked, the program uses the input value as the elongation for all hold-downs in the structure that have combined elongation/slippage, overriding the hold-down database value. If box is not checked, it uses the override value only when a value is not available from the database for the stud size that the hold-down is attached to. This value is also used for the displacement of anchorages attached to gypsum-wallboard-sheathed walls, for which there is no design equation in the CSA O86.      

iii. Shrinkage

If box is checked, the program uses the input value as the wood shrinkage value for all hold-downs in the structure, overriding the value calculated using moisture content and length subject to shrinkage on each floor.

d) Displacement da for Deflection – Wood Properties and Construction Detail Settings

Data for hold-down displacement calculations that cannot be entered independently at each hold-down location is entered here.

i. Default Length Subject to Shrinkage

Used to enter the proportion of the floor depth as input in the Structure input view, plus the depth of other wood members such as wall top and bottom plates that is subject to shrinkage.  This value can be adjusted for individual floors in Structure Input view, it is of primary use in creating defaults for new files for these values. 

ii. Crushing of Bottom Plate at End Stud

The deformation of the bottom wall plate beneath the end chord studs at the compression end of the shear wall. The “factory” default is 0.04 corresponding to lumber loaded to capacity for perpendicular compression according to the USA NDS 4.2.6. A value of 0.02 corresponds to lumber loaded to 73% capacity.

iii. Other (miscuts, gaps, etc.)

Additional sources of vertical shear wall displacement are input here at the discretion of the designer. This could include allowance for studs that are cut too short or without square-cut ends

iv. Bolt hole tolerance

The difference between drilled hole diameter in the studs and the diameter of the horizontal bolt shank. For Assembly displacements that include slippage (see 1b, above), any value greater than 1/16” is added to the published displacement, which includes the effect of standard size bolt holes. For separate slippage and elongation, the entire value is added to the calculated slippage.

6. Hold-down Design

a) Hold-down Location

The program performs the design check for hold-down capacity at each wall or opening end. 

i. Vertical elements

There is currently no mechanism for entering hold-downs at the base of vertical elements transferring a force from an upper storey via a vertical element to a location on a lower story that is not a wall or opening end on that story. so is no hold-down design for those hold-down locations.

b) Design Check

For each design case (wind, seismic, and both force directions), the program checks the capacity of the hold-downs at each hold-down location against the combined factored uplift force. The combined force includes:

-        shear overturning 

-        counteracting dead load

-        wind uplift

c) Design Method

This is a design check only on a hold-down selected for the hold-down location. The program does not at this time cycle through various possibilities to find a hold-down.

d) Anchorages

The program does not perform the design check at hold-down locations where there are anchorages.

7. Output

a) Hold-down Design Table

The Hold-down and Drag Strut table has been split into two tables, one for hold-downs and one for drag struts. The new Hold-down design table includes hold-down capacity design information.

i. Hold-down Device

A column has been added to indicate the name of the hold-down device from the database used at hold-down location. If there is an anchorage there, the program just says Anchorage.

ii. Capacity

The capacity of the hold-down at that location

iii. Crit Resp.

The ratio of combined, factored hold-down force to capacity. A value greater than one indicates a failed design.

iv. Legend

The legend has been split up to show information pertaining to each column on a separate line, edited for clarity. Information about uplift force for perforated walls for staggered openings added. Lines describing new data added.

v. Notes

Note for dead load factor removed and value of factor placed in legend..

b) Hold-down Displacement Table

New table has been added giving the components of shearwall displacement for hold-downs. It is described in the section on deflection output, below.

C:  Deflection Analysis

Shearwalls now calculates the deflection of each wall segment between openings for each design case (wind, seismic, rigid, flexible, E->W, W->E)  according to CSA O86 9.7.   It uses this deflection to

-        determine the storey drift, and check that it is within allowable limits

-        distribute loads to segments within a shearline based on equal deflection of segments

-        determine rigidities for the rigid diaphragm method of distributing loads to shearwalls

As deflection analysis can be costly in terms of processing time, this feature is optional. It is controlled by a checkbox in the design settings.

1. Deflection Calculations

a) Four- term equation

The equation implemented is the four-term equation from O86 9.7.1.1 It is

 

The meaning of the variables is given in the following sub-sections..

The four terms in the equation give the contribution to deflection from the following sources, in order

-        Bending: Bending of vertical shearwall chords (wall segment end studs)

-        Shear: In-plane shear deformation of sheathing

-        Nail slip: Slippage of nails fastening sheathing to top and bottom wall plates

-        Hold-downs: Slippage of fasteners connecting hold-downs to studs, elongation of hold-downs, wood shrinkage and crushing at hold-down location, and additional displacement due to mis-cuts, gaps, etc.   

 

b) Seismic Multiplier

For seismic design, the resulting deflection is multiplied by RdRo/Ie, as per NBCC 4.1.8.13.

c) Unit shear v

i. Load Combinations and Factors

For segmented shear walls, the unit shear v is vertically accumulated serviceability shear force, that is, the shear force per unit foot unfactored by the 1.4 load combination factor for wind design, as per CSA O86 4.2.4.2. 

For seismic design, it is the same as the force that is used for shear wall design and which appears in the elevation view at the bottom of the shear wall.

ii. Distribution of v Within Wall

The second and third terms of this equation apply to the sheathing, which can be different for each side of a composite wall. Both sides require a shear value v (the third term does so indirectly through en.). Refer to j) below for an explanation of how shear is apportioned to each side of a composite wall.

iii. Distribution of v to Segments Within Shearlines

The distribution of v within a shearline depends on the selection of Shearwall Rigidity per Unit Length and Distribute Forces to Wall Segments based on Rigidity in the Design Settings.  For more details, refer to subsection 3 below

d) Shear Wall height Hs

The shear wall height Hs is the distance from the bottom of the bottom wall plate to the top of the top wall plate, exclusive of floor joists or other building elements not part of the wall. 

e) Segment length Ls

The length Ls is the length of an individual full-height segment between openings, and the calculations are performed for each segment separately. 

f) End Chord Bending Deflection

The first term in the equation relates to the in-plane bending of the shear wall chords, that is, the wall end studs.

i. Modulus of Elasticity E

An input field has been added to Shearwalls to allow for input of the grade of the wood end studs. The modulus of elasticity is then taken from the WoodWorks database of material properties.

ii. Cross sectional area A

This is the section area end studs, which are typically built-up members. Shearwalls now allows you to input wall end stud thickness, width, and number of end studs (see C: 4.b) above ), from which the cross-sectional area is calculated.

iii. End Post Composition

Shearwalls does not allow for wall chord posts that are not made up of built-up wall studs but it is possible to model such a situation by typing in a value for the stud thickness, as it has no effect on shear wall design. However you cannot change the wall stud species to the one for the end post without having an effect on shear wall design, which depends on specific gravity. For MSR/MEL you cannot change the grade without having an effect on design. 

g)  Panel Shear Deflection

The second term relates to the in-plane shear deformation of the shear wall

i. Shear Stiffness Bv

The value for shear –through –thickness rigidity Bv is taken from Table 7.3A-C in CSA O86-09, and from the USA Special Design Provisions for Wind and Seismic (SDPWS) Table C4.2.2B for gypsum wallboard..

ii. Shear Value v

Refer to j) below for an explanation of how shear is apportioned to each side of a composite wall.

h) Nail Slip Deflection

The third term isrelated to the slippage of nails fastening the sheathing to the top and bottom shearwall chords, i.e  top and bottom wall plates.

i. Fastener Slip en

The fastener slip en is taken from O86 Table A.9.7 for wood panels and for the USA SDPWS Table C4.2.2D for gypsum wallboard. Note that the slip is non-linear with respect to shear-per-fastener Vn for wood structural panels, but does not depend on v at all for gypsum, it is a constant.  

ii. Fastener Load Vn

The load per fastener Vn is calculated by dividing the shear-per-unit-length v by the user-input panel edge spacing, yielding the force on each edge fastener. 

iii. Composite Walls

Refer to j) below for an explanation of how shear is apportioned to each side of a composite wall.

iv. Interpolation

The deflections are interpolated for loads per nail in between the values listed. It is not interpolated for nail size when non-standard nails are input,  it uses the value for the smaller nail. 

v. Maximum Load Per Fastener

The program limits the fastener shear to the maximum in Table A.9.7. If it is exceeded, it uses the maximum deflection and issues a warning under the Deflection table.  

We determined that this level of loading always results in shearwall design failure for which a failure message is already output anyway.    

vi. Unseasoned  lumber

For unseasoned lumber, that is lumber with fabrication moisture content less than 19%, the deflection values are doubled as per note 2.

vii. Unblocked walls

For unblocked walls, a nail spacing of 150mm is used in place of the actual nail spacing to comply with CSA O86 9.7.1.2.

i) Unblocked Walls

For unblocked walls, the shea rwall deflection is divided by the unblocked factor Jub as per  CSA O86 9.7.1.2.

j) Distribution of v to Sides of Composite Wall

For composite walls, the 2nd and 3rd terms of the equation, shear and nail slippage, apply separately to each side of the shearwall, which may have different materials.

i. Equal Deflections

Shearwalls apportions shear to each side of the wall by adjusting the v value until the deflection due to shear plus nail slippage is the same on both sides of the wall. Note that this equalisation is done regardless of whether equalisation of deflections for all segments along a line is being done according to the selection of force distribution design settings described in subsection 3 below.

ii. Zero Shear

Slippage to non-wood-panel materials is a constant, which in many cases creates a larger slippage deflection than is possible for shear plus slippage even when all load is placed on the wood panel. In these cases, all the force is placed on the wood panel side. The deflection for that segment is the nail slippage plus shear from the wood panel side, and does not include the constant gypsum slippage.

Note that in this case, despite the fact that the entire load is assigned to the wood side for purposes of deflection analysis and storey drift, the program still uses the sheathing on both sides of the shearwall for shearwall capacity calculations according to the procedures for combining shear wall capacity in the CSA O86.

2. Hold-down Deflection

The fourth term in the deflection equation relates to the displacement of the shear wall anchorage devices and the movement of the wood material at the hold-down location. The following sections give the various components which are added to give vertical hold-down displacement da.

a) Displacement

Refers to the elongation in tension of the hold-down brackets or straps plus anchor bolt elongation, plus the slippage of fasteners attaching the brackets or strap to the wall studs.

i. Database value

The hold-down database contains the strength-level displacement that occurs at the maximum capacity.

ii. Displacement/Elongation at Maximum Capacity

If this method (see C: 1.c) above ) is selected for a particular hold-down, the program uses the database maximum value regardless of the force.

iii. Displacement/Elongation at Actual Force

If this method is chosen, then the program divides factored hold-down force by the capacity, then multiplies this ratio by the strength-level displacement.

iv. Additional bolt length

In some cases, separate elongation of the anchor bolt is added to the database deflection. This happens when the published displacement or elongation is for an anchor bolt which is shorter than the one input in Structure input view for the level the hold-down is on. The elongation for the additional length is calculated. Note that in this case, for double bracket hold-downs, the published length is doubled before being compared to the actual length in the program.

The elongation of the length L of bolt that is to be analyzed is PL/AE, where A is the bolt cross-sectional area, E is the steel modulus = 29000000 psi and P is the strength level hold-down force at that location.

b) Shrinkage

Refers to the wood shrinkage that occurs between fabrication and service of the perpendicular-to-grain wood members spanned by the hold-down.

It is calculated when the hold-down does not include a shrinkage compensating device.

i. Calculation

The vertical shrinkage displacement is 0.002 x (% fabrication moisture content – % in-service moisture content) x shrinkage length for that building level from the Structure input view.

ii. Moisture content input

 The fabrication and in-service moisture content are input in the Design Settings. Previously you could input only whether it was greater or less than 19%, for use in nail withdrawal design. Now the actual moisture content is input.

iii. In-service Greater than Fabrication

If for some reason in service moisture content is greater than fabrication, shrinkage is set to zero.

c) Crush

The wood crush as input in the Hold-down settings is applied to all hold-down locations in the program. Typically ranges from 0.2 – 0.4”

d) Additional Components

The additional components in the “Other – miscuts/gaps” input of the Hold-down settings are applied to all hold-down locations in the program.

e) Anchorages

i. Wood panels

Vertical displacement of anchorages as opposed to hold-downs is determined for walls with wood panels via the equation in 9.7.1.1 for this situation. If the wood construction of one side of the wall differs with the other in any way, both sides are calculated and the smaller deflection of the two is taken. This is equivalent to ignoring the contribution to stiffness of the weaker side.

ii. Gypsum wallboard

For walls sheathed entirely with gypsum, the displacement over-ride from the Hold-down settings is used, as there is no guidance for this in the O86. If a wall has wood on one side and gypsum on the other, the gypsum is ignored.

iii. Unblocked walls

For unblocked walls, a nail spacing of 150mm  is used in place of the actual nail spacing to comply with CSA O86 9.7.1.2.

3. Shear Distribution to Wall Segments Within Shearline

a) Design Settings

The way that force is distributed with a line depends on the Design Settings Shearwall Rigidity per Unit Length and Distribute Forces to Wall Segments based on Rigidity.

i. Shearwall Rigidity per Unit Length

In the data group called Shearwall Rigidity per Unit Length, (previously known as Rigid Diaphragm Analysis), a new method has been added to the previous three selections – Use shearwall deflection to calculate rigidity.

 If any of the three methods that were in previous versions of the program are selected, then deflections in general will be different for each segment along the line, as distribution within the line is based on shearwall capacity. The largest deflection is taken to be the one used for storey drift calculations.

ii. Distribute Forces to Wall Segments based on Rigidity

This setting has been added to allow you to distribute forces based on the Use shearwall deflection to calculate rigidity choice to each wall within the shearline based on rigidity. If checked, the program will attempt to equalise deflections along the shearline. If it is not checked, distribution within the line is based on shear wall capacity, and deflections in general will be different for each segment along the line, and the largest deflection is taken to be the one used for storey drift calculations.

b) Equalisation of Deflection

If both the new Distribute Forces to Wall Segments based on Rigidity box is checked, and the new Use shearwall deflection to calculate rigidity button is selected, then the program will attempt through an iterative procedure to equalise deflections on the shearline, by redistributing the shear force v to the segments until the deflections calculated with 9.7.1.11 are the same.

i. Zero Force

Because deflection is highly dependent on aspect ratio of the segments, and the hold-down forces and hold-down devices employed at each segment, deflection can be highly variable along a line, so that some segments draw negligible force. Furthermore, some segments have constant components to deflection (non-wood-panel nail slip, hold-down overrides, extra hold-down components) that yield a deflection with minimal loading that is higher than the deflection on other segments even if all the shearline load was applied to that segment.

ii. If these situations occur, the program assigns zero load to those segments that are drawing negligible loads (less than 1 N), and equalises the deflection on the remaining segments. The segment that gets zero force is treated as an opening or a non-shearwall for the purpose of final hold-down and drag strut calculations.

iii. Non-convergence

The mathematical system used to model shear wall deflections along a line is not necessarily determinate. On occasion, the routine is unable to equalise deflections along a line, oscillating between solutions that do not equalise deflections. In this case, the deflections that arise from the last iteration before a limit is reached are used. 

4. Rigid Diaphragm Analysis

If the design setting Use shearwall deflection to calculate rigidity is selected, the program determines shearline rigidity for rigid diaphragm analysis by summing the rigidities of all segments along the line, where the rigidity is defined as the force on the segment divided by the deflection of the segment.

a) Equal Deflections

If deflections have also been equalised along the line via Distribute Forces to Wall Segments based on Rigidity, then this is equivalent to dividing the total force on the line by the deflection.

b) Change to Manual Input

If you change the setting from Use shearwall deflection to calculate rigidity to Manual input of relative rigidity, in order to adjust the rigidities, the rigidities that appear in the input for a particular wall are the sum of the rigidities for all segments along the line, divided by the wall length.

5. Story Drift Calculations

For seismic design only, Shearwalls implements NBCC 4.1.8.13 by checking the maximum amplified story drift for any shearline against the allowable limits on each level, and for each force direction (E->W, W->E, N->S, S->N).

a) Storey Drift Calculation

i. Maximum Deflection

The maximum deflection is the largest deflection on any shearline, calculated as described above. If deflections on a line have been equalised (see 4.a) above), it is the common deflection of all walls on the line. If not, it is the largest deflection for any segment on the line.  

ii. Deflection Amplification Factor

The deflections are multiplied by the amplification factor from 4.1 8.13 (2) :  Rd Rd / IE . The R values can be input into the Site Dialog, but unless they were over-ridden, they are the values from NBCC Table 4.1.8.9

The importance factor IE calculated from the Occupancy category entered in the sited dialog is used.

b) Allowable Drift Calculation

The allowable drift is calculated according to NBCC 4.1 8.13 (3)..

i. Story height

The storey height hs for each level is the wall height plus the upper floor thickness. 

ii. Occupancy Category

The existing input for Occupancy category from the Site dialog is used.

c) Provisions Not Implemented

i. Sway Effects

The program does not implement NBCC 4.1.3.2(12) regarding sway effects, that is, the effect of vertical loading acting on the structure in its displaced configuration. 

ii. Rotational Deflection

The program does not consider the effect of rotation, that is, the deflection that is caused by the fact that walls on upper floors are rotated due to the deflection on the floor below.  This deflection is not mandated in the NBCC or CSA O86, but is addressed in the APEGBC Technical and Practice Bulletin for .5 and 6 Storey Wood Frame Residential Building Projects.  We hope to implement this in a future version of the program.

d) Output

A new table has been added showing the storey drift calculations for each level and force direction on that level, and indicating success or failure of the storey drift check. Refer to 6.f) below for details.

6. Output

a) Design Settings

i. Shearwall Relative Rigidity

In the Design Settings Table, to reflect the changes in the Settings Input, Rigid Diaphragm Analysis is renamed Shearwall Relative Rigidity. The choices have been modified to be more explanatory.  The new input field for deflection says Deflection-based stiffness of wall elements,

ii. Design Shearwall Force/Per Length

This corresponds to the new checkbox in the input Distribute Forces to Wall Segments based on Rigidity. If this is checked, it says Deflection-based stiffness of wall elements, if not it says Based on Wall Capacity.

b) Shearwalls Materials Table

Because of the need to add information for deflection design, the shear walls materials table has been split into two tables, one for sheathing materials and one for framing materials.

i. Sheathing materials

-   Material name: The material name has been expanded somewhat from the abbreviated name in previous versions, but is still not the full name that appears in the input view.

-   Bv: A column has been added for the value of Bv from Table 7.3A-C in CSA O86-09, and from the USA Special Design Provisions for Wind and Seismic (SDPWS) Table C4.2.2B for all other materials.

ii. Framing materials

For the framing materials table, only one line is needed for each wall design group, instead of the two needed for sheathing materials on each side of the wall. The fields that have been added are

-   Stud grade

-   Stud thickness b  (actual)

-   Stud width d (actual)

-   Modulus of elasticity E, in millions of psi or MPa

A note has been added below the table saying

 

Check manufacturer requirements for stud size, grade, and specific gravity (G) for all shearwall hold- downs.

 

c) Storey Information Table

Columns have been added for the anchor bolt length and the length subject to shrinkage, as input in the Structure Input view.

d) Hold-down Displacement Table

A table has been added to show the components of vertical hold-down displacement da due to the main elongation, displacement, slippage, shrinkage, crush, and additional sources. It has the following fields.

i. Wall and Segment

The wall segment between openings is shown as e.g.  B-3, 2 = second segment on Wall 3 on Shearline B.

ii. Force Direction

E->W, N->S, etc. Can be “Both” if the data is identical in both directions because forces and hold-downs used are the same. In that case only one line is output instead of two.

iii. Hold-down

The hold-down name from the database that is selected at the tension end of the segment. There is limited space for the name, so it may be truncated.

iv. Uplift Force

The unfactored hold-down force at that location, including force transferred from floors above, and including the dead, shear and overturning components..

v. Elong/Disp

This gives the vertical displacement for hold-downs, that is, the combined elongation and slippage

-   Manuf – This is the displacement for the hold-down with the maximum anchor bolt length given in the manufacturer’s literature, or with no bolt contribution those hold-downs that do not include it

-   Add – This is the elongation additional bolt length in excess of the manufacturer’s maximum, or the elongation of the entire bolt for those hold-downs that do not include anchor bolt elongation.

-   da – Vertical displacement due to elongation = Manuf + Add

vi. Slippage

This input does not apply to the Canadian version of the program, and dashes (-) appear in these columns.

vii. Shrinkage da

The calculated displacement due to wood shrinkage. The moisture contents appear in the legend below, and the length subject to shrinkage on each level appear in the Story Information table.

viii. Crush + Extra

The value of wood crushing plus any additional components entered in the hold-down settings appears in one column. Although this column usually holds the same value for all segments, it is possible that at some locations the crush is zero because there is no compression force at the usual compression end of the shear wall.

ix. Total da

The total vertical displacement for each segment, or sum of the displacement, shrinkage, crush, and additional displacements, is output in a column.

x. Hold-down deflection

The resulting horizontal in-plane segment deflection from the hold-downs, or da multiplied by the segment aspect ratio Hs/Ls, is output in a column. This value is then transferred to the Deflection table. ‘

xi. Anchorages

For anchorages, in place of the displacement value, the program outputs, e.g.

(nu =  153 )

giving the value of the unit lateral nail resistance N from O86 10.9.4, needed in the equation for anchorages in 9.7.1.1.

xii. Legend

The legend spells out the calculations that are used to arrive at each value, giving the value of any needed data not in the table such as percent moisture content and steel modulus of elasticity.

e) Deflection Table

i. Wall and Segment

The wall segment between openings is shown as e.g.  B-3, 2 = second segment on Wall 3 on Shearline B.

ii. Wall Group

The wall design group

iii. Force Direction

E->W, N->S, etc. Can be “Both” if the data is identical in both directions because forces and hold-downs used are the same. In that case only one line is output instead of two.

iv. Wall Surface

Some of the columns (shear deflection and nail slip) have different values for different sides of the wall. To calculate them, different v values for each side of the wall are used as well. Therefore for each segment, if it is a composite wall, there are two lines output.

v. Wall surfaces are output as they are in the shear table, as Int or Ext for perimeter walls, and 1 or 2 for interior walls.

vi. Shear v

The unfactored unit shear value on the segment (that is, strength level shear for seismic design) is output. The proportion that goes into each side of the wall for composite walls is given.

This value depends on the distribution method input in the Design Settings, and when deflections are equalised, in many cases it can be zero. See 3.b)i above.

vii. Segment width L

This is the full length of the segment between the outside edges of the wall end studs.

viii. Wall height H

Although this does not change for all segments within a level, it is output in a column as it is integral to the calculations.

ix. Bending

For the bending component, the following are output on the first of the two lines for the wall segment:

-   End stud section area A

-   Resulting deflection

x. Shear Deflection

The calculated shear deflection is output on both lines for the wall segment. The legend shows the calculation.

xi. Nail slip

The following values are shown for the nail slip:

-   Shear force per panel edge fastener Vn

-   en value from from O86 Table A.9.7 for wood panels and for the USA SDPWS Table C4.2.2D for gypsum wallboard.; 

-   Resulting deflection

If the value exceeds the maximum value in the Table A.9.7, the maximum value is used. The program places an asterisk beside the value and issues the following warning.

 

*WARNING - Maximum load per fastener Vn from Table A.9.7 exceeded. Maximum Vn used but it underestimates actual deflection.

 

xii. Hold-down Deflection

This value is transferred from the Hold-down Displacement table, where the components of hold-down displacement are given.

xiii. Total Deflection

Deflection from bending + shear + nail slip + hold-down, as per O86 9.7.1.1

Note that shear + nail slip should be the same for both sides of a composite wall, or else one side has zero force and the shear + nail slip for the other side is used.  If his is not the case because the numerical procedure failed, the largest shear + nail slip is used.

xiv. Legend

The legend spells out the calculations that are used to arrive at each value, giving design code references and where to find data not in this table, e.g. the Stud modulus of elasticity in the Framing materials table.

f) Storey Drift Table

A table has been added to the program to show the storey drift calculations ASCE 7 equation 12.8-15 and the allowable storey drift from ASCE 7 Table 12.2-1. The allowable drift is shown for each level; the maximum storey drift for any shear wall on the level is shown on one line for each force direction below the allowable values.

i. Wall height

The wall height h is shown for each building level, along with the storey height hsx for that level, which is the wall height plus the upper floor thickness. 

ii. Allowable drift

The allowable drift calculated according to NBCC 4.1 8.13 (3) is shown for each level only.

iii. Amplification Factor Rd Ro

The value of the force modification factors Rd * Ro as they are used for the amplification in 4.1 8.13 (2), are entered on each line. Note that these values can be different for different force directions.

iv. Importance Factor I

The importance factor I calculated from the Occupancy category entered in the sited dialog. This is the same for the entire structure, but is repeated in the table to show all variables for a calculation on the same line.

v. Maximum Deflection and Line

For each force direction on each level, the table shows the largest of the deflections on any shearline in the force direction as well as the line the maximum was on.

vi. Amplified Deflection

The program shows the maximum amplified deflection on the same line.

vii. Response Ratio

The ratio of the maximum amplified deflection to the maximum allowable is shown.

viii. Failure Message

The program places an asterisk (*) beside any response ratio that is greater than 1.00. A red failure message appears below the table.

ix. Legend

A legend has been added explaining each column in the table.

g) Table Legends

To all the above tables a legend has been added to the table or an existing legend improved such that it shows detailed information pertaining to each column on a separate line.

h) Show Menu and Display Options Toggles

For all the above tables, items have been added to the Show menu and the Display checkboxes in the Options settings that allow you to turn off the tables in the screen display and in the printed output, to reduce the volume of output, similar to all other tables. 

i) Elevation View

i. Segment Forces

The force on each shear wall segment arising from the distribution of forces described in 3 above are depicted by small arrows at the top of the wall at each segment, with the force in pounds on that segment shown.    

D:  Shearwall Design Iterations

This section refers to the iterations needed to design shearwalls for the unknown values in order to determine the stiffness and/or capacity needed for load and force distribution, then to go back and redesign based on the new load distribution.

1. Previous Versions

a) Structural Iteration for Irregularities

For seismic design, the program went through two iterations of designing the entire structure as follows.

i. Iteration 1

The program designed using the user-input method of designing for hold-downs and drag struts.

ii. Iteration 2

The program determines irregularities on the structure, and if Applied Force had been used as the method of determining hold-down and drag strut forces, the program program redesigns the entire structure, determining hold-down and drag strut forces for the shearlines affected by irregularities by shearwall capacity, to comply with NBCC 4.1.8.15-6 where applicable.

b) Rigid Distribution

i. Rigidity based on Shearwall Capacity

The program designed walls for flexible diaphragm design, and then used the rigidities based on the capacity of those walls for rigid diaphragm shearwall design. .

 It did not go back and recalculate rigidities for the new walls designed for rigid design, and continued to show the flexible-designed shearwall rigidities as the rigidities of the rigid-designed walls.

ii. Equal Rigidity or Manual Rigidity Entry

For these distribution methods, the rigidity is independent of shearwall design, so no iterations were necessary.

c) Distribution within a line

Before the introduction of deflection analysis, if you selected not to allow dissimilar materials on the line, it was possible to determine load distribution within a line based on relative capacities and identify the critical wall for design ahead of time and an extra design iteration was not needed.

If dissimilar materials are allowed, the program must design each wall separately so that the design could result in a redistribution of loads, and a iterations were peformed to design the wall and redistribute loads until a there was no difference in walls designed.   

d) Hold-down vs Anchorage Loop

If the user chooses to allow anchorages, the program does several iterations of design based upon trying to counteract a failed design by increasing the Jub factor. On the first loop it places the hold-downs only where they are required by CSA O86. Then it places them at the ends of the shearline, then at the ends of all walls, then at the ends of all segments.

This acts in concert with the Design Setting that indicates whether hold-downs should be at those locations, and the setting that allows you to over-ride these locations to achieve design. 

2. Structural Iteration for Irregularities

The program still performs two designs of the structure for the purposes of determining irregularities, however this is now part of a larger design sequence that includes a third run for final design check.

Note that the iteration for irregularities has taken on added significance because of the introduction of deflection analysis. If the program automatically calculates certain hold-down forces using shearwall capacity , these hold-down forces impact the hold-down component of the deflection equation. 

3. Design Iterations Per Level

a) Reasons for New Iterations

i. Stiffness Analysis

Now that load distribution can be affected by the stiffness due to deflection analysis, it is no longer possible to predict ahead of time which wall segment will be critical design, and an iterative procedure is required.

ii. Rigid Analysis

It is an improvement to the program to redesign walls for rigid analysis based on the stiffnesses from the rigid analysis. This improvement became especially important because of the variations in wall rigidity that result from deflection analysis.

Therefore, on each level, first for rigid, and then for flexible, the program runs through two iterations of shear wall design.

b) Iteration1

The first iteration is used to design shear walls to determine rigidities and capacities for load and force distribution for the second, final design iteration.

i. Distribution to Shearlines

For flexible analysis, distribution to shearlines is independent of shearwall design, and is the same for both iterations.

For rigid analysis, if Shearwalls have equal rigidity or Manual input of relative rigidity is selected, then the relative rigidity of the shearlines is also independent of shearwall design, and is calculated by the sum of the wall lengths multiplied by either 1 or the manual input.

For the other rigid analysis options (Use shearwall capacity or Use shearwall rigidity), the rigidities of the shearwalls designed on the second iteration of flexible design are used as the rigidities for the first iteration of rigid design.

ii. Distribution within Line

With shearline forces established, on the first iteration, for both flexible and rigid design:

If Distribute forces to wall segments based on rigidity is not selected, or if Shearwalls have equal rigidity is selected, the program distributes equal force per unit foot to segments within the line.

If Manual input of relative rigidity is selected, then the user input rigidities are used to distribute forces to each shearwall.

Otherwise, the force is distributed each shearwall using the relative capacities of the shearwalls.  Since walls are not yet designed, the deflections are not known at this point, and the selection of Use shearwall deflection to calculate rigidity must use the capacity method on the first iteration.

iii. Shearwall Design

With possibly different forces distributed to each wall, the walls are designed. This shear wall design is used to determine rigidities for the second iteration.

c) Iteration 2

i. Force distribution

If Shearwalls have equal rigidity or Manual input of relative rigidity is selected, there is no reason for a second iteration, and the program stops at the first iteration, and delivers design results for the shear wall design for the first iteration.

Otherwise, using the walls designed with iteration one, the program determines the force distribution using rigidities derived from either shear wall capacity or deflection analysis, according to the design setting selected. The force distribution is for distribution of loads to shearlines using the rigid diaphragm method, and distribution to forces within shearlines using both methods.

ii. Distribution to Shearlines

The rigidity of a shearline is estimated using the capacity method by the capacity of the designed wall on that shearline, in lbs/in, and by the deflection method by

Σ Fi/DI,

where Fi and DI, are the forces and deflections on each segment. If forces are also distributed within the line based on deflection, so that deflections are equalised, this is just F/D, the total force over the common deflection. Loads are then distributed to the lines using the torsional rigid diaphragm method.

iii. Distribution within Shearlines

If the setting Distribute forces to wall segments based on rigidity is selected, for both the rigid and flexible method, then the program calculates the force distribution on the line based on relative rigidities of segments on the line. Otherwise equal force distribution is assumed.

If Use shearwall deflection to calculate rigidity is selected, then different forces are placed on all full-height segments.

If Use shearwall capacity is selected, the different forces can be placed on each shear wall. At this stage, the program distributes loads based on the actual factored capacity of the walls from the last iteration.

iv. Design

Each shear wall is again designed. Note that these walls may have different deflections and possibly capacities than those used to distribute forces to design the walls; this is dealt with by the Final Design Check, below. 

d) Number of Iterations

It would have been possible to continue this process to further iterations. This was not done because:

i. Distribution of Loads to Shearlines

An iterative procedure for rigid diaphragm analysis would tend to concentrate loads on a particular shearline. That is, a heavily loaded line would require more capacity, would become more stiff, would draw more load, and so on. This is not a desirable shear wall design for other reasons.

ii. Final Design Check

The final design check described below now traps and indicates to the user those rare cases where walls passing on the second iteration failed the final design check. This was deemed preferable to the increased processing time that would be needed for all designs if there were more iterations. 

iii. Non-convergence

If we established the condition for ending the iterations that shear wall design did not change from one iteration to the next, it would be possible for the procedure to oscillate from one solution to another without ending.

4. Final Design Check

a) Structural Design Check

For the entire structure, forces are distributed based on the capacities, stiffnesses, and shear resistance distribution of the walls designed on the second per-level iteration and the hold-down and drag strut procedures determined value from the second structural iteration for irregularities, if one was needed.

The designed walls are then checked against the new forces, and the results reported in the Design Check output:

b) Reasons for Check

i. Output Report Consistency

This ensures that the output reports show the force distribution, the r value, the shear wall deflection, and shear wall design capacity from the same set of walls.

ii. Possibility of Failure

Although it rarely occurs, it is possible that the walls designed on the second iteration cannot withstand the forces created from their rigidities. The design check shows this situation, indicating to the user via the following warning message that the problem is to do with design iterations and can be remedied by more manual input.  

 

Warning: For shearline(s) [ A, B, C, ..., 1, 2, …], a shearwall that passed the design check on the initial run failed the final check when forces were redistributed to shearlines and/or wall segments within a line using [ shearwall deflection, shearwall capacity]. Try to adjust wall materials to achieve a passing design, or choose a different force distribution option in the Design Settings.

E:  Other Engineering Design Issues

1. Shear Strength of Unblocked Shearwall (Bug 2250)

The shear strength for an unblocked wood-based shear wall, according to the asterisked note to CSA O86-01 Table 9.4.4, is the shear strength for a blocked shear wall 600 mm stud spacing and 150 mm edge nail spacing, regardless of the actual composition of the shear wall, multiplied by the Jub factor.  Shearwalls instead used the actual nail and stud spacings for the shear wall to determine shear strength, ignoring the note. Since 600 mm stud and 150 edge spacing are the maxima, this created non-conservative resistances. The program now applies the note.

Note that the asterisked note for a strength increase in Table 9.5.1A is not applied, even if the actual stud spacing is 400 or less, because it is overridden by this requirement.

2. Gypsum Wall Board for Wet Service Conditions (Bug 2251)

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