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Important Note – These are descriptions to changes implemented in WoodWorks Shearwalls for version 11 and may not reflect current program behavior.
Extensive changes to several of the Design Settings was necessitated by the following changes to the SDPWS:
the Aspect Ratio Factors in SDPWS 2015 4.3.4 and adjustments in 4.3.3.4.1 are now identical for wind and seismic design, whereas in SDPWS 2008 Table 4.3.4 the factors applied only to seismic design for wood structural panels, and differed between seismic and wind for fiberboard.
For capacity-based force distribution, gypsum-based materials or lumber sheathing are no longer allowed, as per SDPWS 2015 4.3.3.4.1, and for wood structural panels and fiberboard, an "adjustment" is applied to narrow segments, rather than the Aspect Ratio factors in 4.3.4 that apply to deflection-based distribution.
The SDPWS now recognizes only capacity-based and deflection based force distribution methods.
The SPDWS C4.3.3.4 clarification of the definition of "similar materials and construction" along a shearline
The changes to the design settings also, present the options more understandably, use the current SDPWS terminology, implement SDPWS provisions that were previously omitted, and simplify special cases such as the treatment of fiberboard.
The data group previously called Shearwall rigidity per unit length… is now called Rigidity for shear force distribution based on…
It is no longer necessary to state that it is "per unit length" because of the removal of the Equal rigidity and Manual rigidity discussed below.
The setting Use shearwall capacity to approximate rigidity is now called Shearwall capacity (wood panels and fiberboard only). If selected, it causes the new Ignore non-wood panel contribution setting for Walls entirely sheathed with gypsum-based materials or lumber sheathing to be checked and disabled, so that these materials do not contribute to force distribution, design or deflection calculations, as per SDPWS 4.3.3.4.1.
The setting Use shearwall deflection to calculate rigidity has been renamed Deflection of wall segments or perforated walls. This indicates more precisely what the method entails than the use of the word "shearwalls".
This option has been removed because as it is not allowed by the SDPWS and has no physical justification.
This option has also been removed for the following reasons:
It was originally in the program to allow you to enter a rigidity based on deflection calculations that the program did not do at the time, but now does.
There is no way of judging whether this rigidity is based on capacity or deflection, so no way of deciding which of the aspect ratio factors (SDPWS 4.3.4) or adjustments (4.3.3.4.1) to apply.
Note that some users had been using this input to model proprietary non-wood shear resisting elements, however that was not its original intention and we plan to implement a more rigorously designed implementation of proprietary elements in the near feature.
This setting has been removed, as it’s purpose was to use deflection-based or capacity-based distribution of externally applied load to shearlines, but to distribute forces to segments equally within the shearline. Since the Equal rigidities option has been removed because it is not allowed by SDPWS, this option has been removed by the same reasoning.
If Equal rigidities or Manual rigidities was active in a project file from a previous version of Shearwalls, or Distribute forces to wall segments based on rigidity was not selected, the program changes the distribution method to your default method, and the program issues a message after the file is loaded explaining the reason.
Unless you have changed it to capacity-based, the default distribution method is deflection-based.
The data group previously labelled Ignore non-wood panel contribution… offered a grid of settings based on wind vs seismic on one axis, and whether it was for all walls or only when combined with wood structural panels on the other axis.
The group is now labelled Ignore contribution of…, then provides three checkboxes as follows:
Checking this setting has the same effect as checking both the corresponding settings for wind and seismic design in Version 10, that is, it causes the program to neglect GWB, plasterboard and other gypsum based materials and lumber sheathing in design, deflection calculations, and capacity-based force distribution when there are blocked structural wood panels or fiberboard on the other side of the wall.
It is no longer disabled and checked when the All gypsum based materials for seismic design setting is checked, as the corresponding seismic setting was when For all walls/ Seismic was selected. The operation of these inputs is now independent, because the new setting applies to both seismic and wind design.
It is disabled and unchecked when Allow 3.5:1 aspect ratio is unchecked, as was the corresponding seismic setting in Version 10 (the wind setting did not do this).
The words walls with narrow segments were added to describe a new condition that was added to improve this feature. For the non-wood-panels to be disregarded, the wall or shearline must contain at least one segment that has an aspect ratio less than 3.5:1 but greater than 2:1 for structural wood panels and 1:1 for fiberboard. This way, the program is not disregarding shear-resisting materials throughout the structure just because it is required for a few short shearwalls.
This change was required also to maintain the usefulness of this setting, because it previously existed primarily to allow you to ignore these materials for seismic but not for wind, which is no longer necessary.
This operates the same way as the previous All walls setting under Seismic, that is, all non-structural-wood panels will be neglected for design, deflection calculations, and capacity-based force distribution when the setting is checked.
Previously, checking this caused the setting for walls combined with wood panels to be disabled and checked for seismic. This no longer happens, because the corresponding setting now applies to both wind and seismic.
Because of this, it is now possible to have this setting checked and the setting for ignoring these materials when combined with wood structural panels unchecked. In this case, the restriction that all these materials are ignored takes precedence and the program disregards the setting pertaining to when they are combined with wood structural panels.
You cannot set this setting, it is always disabled, and is automatically checked when the Rigidity for shear force distribution setting is set to Shearwall capacity. Its purpose is to inform you of that the restriction based on SDPWS 4.3.3.4.1 is in effect, that is, that only wood structural panels and panels are allowed unless the force distribution is based on deflection analysis.
When this checkbox is checked, any wall that has either gypsum or lumber sheathing on both sides, or those materials on one side and nothing on the other side, is entirely neglected for design, deflection calculations, and capacity-based force distribution.
The informational text including fiberboard has been removed, as it is now explained in the checkbox text.
If a file is opened from a previous version that had All walls / Seismic checked, then the corresponding checkbox is checked for wind design.
If a file had either of the settings for wind or seismic, when combined with structural wood panels checked, then the corresponding setting for both materials is checked.
The setting for Walls entirely sheathed with gypsum … is checked based on whether capacity-based distribution or deflection-based distribution is checked when the file is opened.
This setting allows you to avoid aspect ratio penalties by excluding the contribution of shearwall segments with ratios between 3.5:1 and 2:1 (WSP) or 1.1 (fiberboard). Previously, the wood structural panel option applied only to seismic design.
The data group title for this has changed from Seismic wood panels, and fiberboard to Wood structural panels and fiberboard.
The name has changed to Allow 3.5:1 aspect ratio to reflect current SDPWS terminology.
Unchecking this causes the setting under Ignore non-wood… called Gypsum-based materials … when combined with wood… to be disabled and unchecked, as it currently is for the corresponding checkbox for seismic design in Version 10.
This setting is applied to wind design in the identical manner that it previously was for seismic design only, that is, if it is checked, any segment between less than 3.5:1 but greater than 2:1 for structural wood panels and 1:1 for fiberboard is not considered a full height segment and is not apportioned any force for design.
This setting was in the program to allow you to include proprietary shear resisting elements that are not subject to aspect ratio limitations for wood shearwalls. Since the ability to enter rigidities for these elements was removed as described above, this input would have no function other than to circumvent limitations mandated by the SDPWS. Accordingly, it has been removed until we implement a rigorous treatment of proprietary elements in future version.
The SDPWS Commentary C4.3.3.4 clarifies what is meant by "same materials and construction" along a shearline to mean that classes of materials such as wood structural panels, gypsum wallboard, fiberboard must be the same, but details such as the sheathing thickness and nailing patterns do not have to be identical. However, the current operation of the program forcing these materials to be identical has advantages in terms of processing time and generating practical designs. For this reason, a Design Setting has been added allowing you to force the use of identical materials along a shearline.
The checkbox for this setting reads All shearwalls on a shearline have identical materials and construction.
The default value is unchecked, that is, non-identical materials along a line are allowed (but the program still forces all materials to be of the same material class, as described in .
When files from previous versions are opened, the capability is de-activated, because the previous designs did not allow this. However, a message appears informing you of the ability to change the setting and allow non-identical materials along a line.
A setting has been added to allow you to choose between the 3-term deflection equation from SDPWS 4.2-1 and the 4-term equation from C4.3.2-1. Previously only the 4-term equation was included. The implementation of the 3-term equation is described in section ).
The default option is 3-term, because that is the option in the main body of the SDPWS rather than the Commentary, however, for more accurate deflections, 4-term is recommended.
Existing files from older versions use the 4-term equation, so that the designs do not change.
A setting Perforated shearwall Co factor calculation has been added to allow you to choose between the formulae in SDPWS 4.3-5 and 4.3-6, and Table 4.3.3.5 in determining the Co factor that is applied to the capacity of perforated shearwalls. Previously, the program implemented only Table 4.3.3.5.
By default, the program uses the equation, however files from previous versions will continue to use the table when first opened.
Shearwalls now includes a Storey drift table for wind design (see ). A design setting has been added to allow you to set the story drift limit as a proportion of shearwall height. The default value is 1/ 500 which is midway in the suggested range of limits of 400 to 600 by ASCE CC.1.2. You can change this using Save as default for new files.
Adjacent to the input of Moisture Content in the Design Settings, the program now indicates whether the value is considered dry or wet by the NDS. This is now also indicated in the Design Results echo of the Design Settings.