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This feature allows for:
support types and materials.
Input
Span Type
An input has been added to specify how the program interprets the span values entered:
Design Span
This is the distance between support points on beams. Support points for exterior supports are ½ the minimum required bearing length from the inside of the support. For interior supports, they are at the centre of the support.
Clear span
This is the distance between the inside faces of the supports, for all spans.
Full span
This span is measured from the outside faces of exterior supports, to the centre of interior supports. It is the beam length for single-span members.
Support Type
For each support, you can specify the following:
Hanger
The hanger indicates a steel hanger is used for the beam. . If this is chosen, supporting member design will not be part of the bearing design routine, and the Material, Species and Grade inputs will be unknown. It will, however, have a list of bearing sizes representing common hanger lengths.
Other non-wood
This is chosen to indicate that the supporting member is made of concrete, steel or some other material not designed by WoodWorks. If this is chosen, supporting member design will not be part of the bearing design routine, and the Material, Species and Grade inputs will be disabled and blanked out. . This option will also not have a list of bearing lengths associated with it, and will design for minimum or rounded minimum instead.
This option is available for supported beams and joists.
Sill Plate
This choice is for a 2-inch thick wooden member which is assumed to lie on the flat, usually affixed to a concrete or block foundation. The program will implement a special set of sill plate database materials, using essentially joist database files. The bearing length information is taken from the “d” dimension of the sill plate materials.
This option is available for supported beams and joists.
Beam
The supported member is assumed to be a beam, so that the material, species, grade, and bearing length information will come from our beam database files. The bearing length info is taken from the “b” dimension of the beam.
This option is available for supported beams and joists.
Column
The supported member is assumed to be a column, so that the material, species, grade, and bearing length information will come from our column database files. The bearing design choices will be taken from all of those from the “b” or “d” dimension of the column could be oriented either way. .
This option is available only for supported beams.
Wall
The supported member is assumed to be a wall, so that the material, species, grade, and bearing length information will come from our wall database files. The bearing length information is taken from the “d” dimension of the wall plate.
This option is available only for supported joists.
Material, Species, and Grade
You can input these parameters for each supported member, similar as the inputs for Material, Species, and Grade for the main member. The information comes from the WoodWorks materials database.
Bearing Length – Main Lb
This field represents the length parallel to the supported member that is supported. The program will allow for
entry of a custom bearing length,
selection of a length from a list of suggested lengths,
selection on “Unknown” in which case the program will determine the bearing length according to the choices described
Bearing Length – Point Load
This field comes into play if there is a point load of any type on the support. It is the width of a column or a beam or beam supported by the main member, and transferring a load to the main member. It is needed to implement CSA O86 5.5.7.3-4. It is measured parallel to the main bearing length Lb.
Greater than 2 Lb
This choice allows you to specify that it creates an area greater than the maximum bearing area given in O86 5.5.7.4. All bearing lengths longer than this will result in the same bearing resistance.
Equal to Lb
This choice models the situation where the point load is exactly the same width as the member supporting the beam, as when there is an identical column below and above the beam.
½ Lb
This choice is included to allow for files from previous versions to have the same design as before, as it was the assumption with previous versions of Sizer that the supported point load was ½ the length of the main member bearing length..
Bearing Widths
Main member
This represents the width perpendicular to the beam that it is supported, that is, the depth of a supporting column or the amount supported by the end of a beam that extends only part way onto the member. Other situation for which only part of the beam width is supported include a mortise-and-tenon joint or a beam supported by side-hangers.
Point Load
This represents the width perpendicular to the beam of the member supporting transferring a point load from above. This could be a column, or a beam extending only part way onto the main member, or a member supported via a mortise-and-tenon or other joint which only partly bears on the member.
Choices
You can enter a value here or select
Same as beam.
If you designate it “same as beam” the program will use the final design width of a beam that initially has unknown width.
Bearing at Support End
The checkbox “Bearing at Support End” indicates that the supporting member ends at the supported member, so that the bearing length factor CB is not applied.
For unknown bearing length…
This field allows for a choice of bearing design option for all supports in which Unknown is selected as the Bearing length choice. The choice affects the actual bearing length that the program determines is supporting the beam.
Use exact minimum
In this case, the program will design for minimum required bearing length and use that exact length as the bearing length for each support. This is how the program currently works.
Round minimum up to nearest
With this choice, the program determines the minimum required bearing length, and rounds it to the nearest increment as indicated by the user.
This option corresponds to the case where the beam sits only partially on an end support, but the user wants to have a bearing length and a total beam length that are reasonably round numbers for measuring and cutting.
From Bearing Length list
In this case, the program rounds up to the next choice in the dropdown box that was derived from the section sizes of the supporting members or from the standard hanger sizes.. Refer to vi Bearing Length, above, for the choices of section sizes for each member type and orientation.
End Supports: Round minimum; Interior: From bearing lengths
This option allows the user to model a situation where a beam sits only partially on end supports but fully on interior supports. Enabled only when there are interior supports in the member, including cantilever supports. Its behaviour is a self-explanatory combination of the previous two options.
Bearing Length and Design Spans
This feature related to the span input in that the choice of the bearing length method used has an impact on either the actual length of the beam, the clear span, and/or the design, depending on whether the user chooses to enter clear span, design span, or fixed beam length.
Clear span or design span
If the user enters clear span, then the bearing design choice will not affect the length of design span, as the design span is clear span + minimum bearing. Similarly, if the design span is entered ( as it is currently in Sizer), the clear span is not affected. For these cases, only the beam length will change based on the choice of bearing length design method.
Actual beam length
If the beam length is what is assumed to be entered, then the choice of bearing length method will affect the length of design span and the length of clear span. As a result, this choice will have an impact on the shear, moment, reactions, etc. Indirectly, due to change in clear span, it will have an effect on notch design and, shear at distance d,. as well.
Minimum Bearing Length Options in Design Settings
A group in the Design Settings called Minimum Bearing Length has been added with two inputs
End supports
Interior supports
Beside the End supports item, there is a checkbox that says
Use to determine design span.
End Supports/Interior supports
The values entered in these boxes indicate the smallest bearing the program is able to design for, for interior and end supports separately. If the program calculates a minimum bearing less than this value, it overrides it with the value entered.
Use to determine design span
Some user may wish that the program never design a bearing less than some practical amount, say 3.5”, however they may wish to take advantage of the reduced design span from using only the minimum required bearing length. For his reason, we allow them to opt out of using the minimum bearing they entered in their calculation of design spans. The program in this case uses the minimum required bearing for design span, but the user entered span for bearing design.
Drawing
Support Symbols
The following symbols are shown for each hanger type
Hangers
A solid, thick, L-shaped black bracket when at the end, a plate when in the midspan.
Other non-wood
A diagonally hatched rectangle, same thickness as a hanger plate.
Sill plates
A 1.5” deep board the width of the bearing length input or design, with diagonals indicating it is a cross section, resting on a slightly wider rectangle open at the bottom meant to convey a concrete or other foundation.
Beams
A rectangle representing the support cross section with diagonals, with the beam depth set to 5.5” (the user does not enter this value). Note that there is no attempt to show built-up supports as composed of separate plys.
Columns
Two lines, open at the bottom, spaced the bearing length apart, meant to convey a continuing column,
Walls
Two rectangles with diagonals, each 1.5” deep, representing top plates, with a rectangle open at the bottom to convey a continuing wall stud.
Support Text
The following text appears beside each support .
Bearing length
Bearing length formatted as per user setting for Sections in the Format settings ( previously it was unresponsive to that setting) in format
Lb = [length] .
For unknown bearing before design it says Lb = unknown; once designed it gives the designed bearing length.
Bearing width
The user-input bearing width is output if different than beam width.
Material
On the following line, the material shown is just the major category of material, that is Glulam, Lumber, Timber, MSR Lumber, I-Joists.
No material type is shown for hanger or “other non-wood” supports.
Support Type
After material, the word Column, Wall, Beam, or Sill Plate, so the line says, e.g. Lumber Column.
No support type or material is shown for Other non-wood.
Species and Grade
The species and grade of wooden supports is shown on one line below the material.
Spans
The program now outputs two dimensioned lines at the top of the screen, the upper one spanning the entire beam and giving the actual length of the beam, the lower one dimensioning each clear span. The design distances are shown at the bottom.
The words Design, Full, and Clear are placed the left of the drawing to indicate what each one means.
Beam Length
The program now shows the total beam length, instead of each span individually dimensioned.
The length of the new dimension line for the overall length of the member is now adjusted for sloped members to show the distance from the bottom edge of member at the lower support to the top edge of the member at the upper support.
Clear Span
Each clear span, or distance between the edgeof supports, is shown below the beam length.
Design Spans.
The design spans are shown as numbers at the bottom, with zero starting at the first reaction point. This scale correlates with the analysis diagram and location of analysis points, points of interest, etc.
Unknown Bearing Lengths
When bearing lengths are input as unknown, or design has not been performed so that the minimum required bearing length is not known, only the value for the input span type, the other values are given as “unknown”.
The values for unknown bearing length and minimum bearing length from the most recent design are used for span calculations after design, even if the you changes the beam length, materials or other input since they were designed.
Beam material specification
One the design is performed, the material specification is shown on the screen in the same format that appears in the Design Check output.
Load Input
Unknown Bearing
Full line loads
When you have selected unknown bearing he program initially creates loads that extend over the user-input span type only, as the precise dimensions of the other span lengths are not known. After design, the program adjusts the loads to extend over the full uniform span
Point Loads
If design span is entered, the program assumes the point loads are applied relative to the reaction points, so that if a point load that was at 4’ will be adjusted to be 4.2” from the beam end when 2” designed bearing length is added. This ensures that point loads over supports remain over supports. The values in the load input are adjusted accordingly
If clear span is input, the point load is shifted by the full input bearing width. A point load originally entered at the end of the clear span will wind up within the design span and not over the support. As you cannot enter a load outside the span of the input span type, in order to input a clear span with a point load over support you must either adjust the load location after design or input a known bearing length.
If actual span is input, the point loads remain at the input points before and after design. Point loads entered at the end of the member will remain there after design, and be applied to the bearing support and not over the design span.
Partial line loads
The behaviour of the start and end points of partial line loads is identical to the behaviour of point loads. The program does not adjust the magnitude of a partial line load when making adjustments to the start and end point locations.
Known Bearing
If the bearing length is known, then only the minimum bearing length is unknown before design. This changes the load entry as follows:
Design span
Since the minimum bearing length is not known, the situation is the same as for unknown bearing, the program does not know the minimum bearing, clear span, or actual length of the member, and adjusts the load location based once design is performed.
Clear span
In this case, the program is able to determine the actual span, and a line load is considered to span the entire member both before and after design, and one can place a point load on the support outside of the design span from the start
Actual span
In this case also the length of the beam is known and a line load extends the full length both before and after design, and that the location of point loads and partial loads is also invariant.
Change of span type after load entry
The program makes the necessary adjustments to the loads if the span type is changed after the load entry.
Uniform line loads
The program adjusts the loads so they extend the length of the input span type when the actual beam length is not known, and the full length of the beam when it is known.
Partial loads and Point Loads
These loads just maintain their start and end points, or the point load location, with respect to the start of the new span type. This can cause a point load that was over a support to move to be within the design span if it is not adjusted manually.
Loads Analysis and Design
Determination of Design Span
For spans, the program considers the design span to be the clear span between support edges plus:
Interior supports
For interior supports, ½ the actual bearing length is added, whether it is user input or designed by the program
End supports
For end supports, it is ½ the lesser of the following:
the minimum required bearing length
the user input actual bearing length.
Minimum Required Bearing Length
The minimum required bearing length is calculated the program currently does. . In addition, a setting has been added to provide a minimum absolute bearing length regardless of the force on the support, and another to indicate that that minimum should override the calculated minimum based on force when determining the design spans. See A: 1.c) above for these settings.
Iterative Design
Unless Design span is chosen as the span choice, the calculation of minimum bearing length affects the design span length. This in turn affects the reactions that are on the supports, which in turn affects the min required bearing length, which in turn affects the design span…
Similarly, if Unknown bearing length is selected, the reactions determined affect the bearing length required, which in turn affect the position of the edge of the support from which design span is measured, which affects the design span, which affects the reactions used for bearing design…
For these reasons, the program now performs iterative analysis and bearing design on the member, first determining reactions with the longest span possible given the bearing and span choices, then determining the bearing lengths required, then calculating design span, then readjusting. The program iterates until the difference in design span between two iterations is not noticeable (0.1 mm). Generally 3-4 iterations are required.
Loads Directly over Supports
Point Loads
A load that is within the design span, but over a portion of a known support that is within the span, is treated as a point load within the design span and analysed for shear, moment, bearing, etc, as before.
Point loads that are applied outside of the design span, that is, to the left of the support point of known bearing at a left end support and to the right of the support point of a right end support, are applied directly to the bearing design of the support and are not considered part of the design span.
Line loads
The portion of the line load that is within the design span, but over a portion of a known support that is within the span, is still treated as a load within the design span and analysed for shear, moment, bearing, etc, as before
Sizer can now apply the portion of the line load that extends outside of the design span, that is, to the left of the support point of known bearing at a left beam end, directly to the bearing design of the support.
This is implemented for all line loads – full, partial, uniform, trapezoidal, triangular.
You can disable this capability via an option ion the load input view – Line loads applied to design span only
CSA O86 5.5.7.3 – Effect of point loads near support
Sizer version 8 implemented clause 5.5.7.3 for the Effect of point loads within distance d of a support by arbitrarily assuming that the Lb2 for member transferring the point loads to the main member was ½ the minimum required bearing length of the main member. Now Sizer allows you to enter this value, and to accommodate unknown bearing lengths, to specify that it is one of:
Point Load >= 2Lb .
If this option is chosen the limit of 1.5 Lb is reached, so all values greater than 2Lb have the same bearing resistance. Clause 5.5.7.2 for all loads resolves to the same equation as 5.5.7.3 does for point loads only, so that in effect you are disabling the 5.5.7.3 check for point loads by selecting this.
Measurement of Distance d from Support
CSA O86 5.5.7.3 says to use the distance d from the “centre” of the support. This is shown in the second of the three diagrams below. Sizer measures it from the support point at the minimum required bearing length, as shown in the first diagram. It is possible using this approach to include a load that would not be included using a literal interpretation of the design code, as shown in the figure.
This approach is taken to avoid the possibility for shallow members and wide supports that a load that is over the support would not be included, as shown in the third of the diagrams.
Bearing Width and Average Area
Sizer also allows input of bearing width b. The design code says to use the average A, which it defines as the average length multiplied by the average width. However the average of one set of distances multiplied by the average of another set of distances, is not the same s the average of the areas derived by multiplying each corresponding distance together. We think the intent is to average the areas, so referring to Figure 14 “ Bearing Lengths and Widths on page above, the average area is the average of the light gray and darker gray regions, not the average of the bearing lengths shown multiplied by the average of the bearing widths.
Size Factor Kzcp for Supporting Member
The size factor Kzcp depends on the member width to depth ratio, and in general the member depth is not known, so that the size factor Kzcp is set to one, assuming the support is deeper than wide. Exceptions are made in the following cases:
All glulam supporting members are assigned a member depth of 1.5 inches, corresponding to the depth of a lamination. Glulam members thus have a size factor greater than one, unless the bearing length for beams or the column width is less than 1.5”.
Sill plates made from dimension lumber are assumed to have a depth of 1.5”. These will have a size factor greater than one, unless the bearing length for beams or the column width is less than 1.5”.
Wall bottom plates made from dimension lumber are assumed to have a depth of 1.5 so these will invariably have a size factor greater than one.
Unknown Bearing Length
For glulam beams, and for lumber sill plates supporting beams and joists, the size factor cannot be computed when the bearing length is unknown. Therefore the size factor is set to 1.0 when determining the minimum required bearing length. The size factor is then computed when the bearing length is established.
For this reason, the strength ratio can be less than 1.00 even when you choose to show the exact minimum required bearing length as your support length.
Unknown bearing lengths do not affect column and wall calculations, as the supporting member width dimension is not the same as the bearing length dimension.
Notches
The uses the designed or user-input bearing length as the width of tension edge notches, rather than the minimum required bearing length, as before.
The terminology Min. has been dropped, as it is now the actual length of the notch.
Shear-at-a-distance d
According to CSA O86 5.5.5.2 line loads within a distance d of a support do not contribute to shear, Formerly Sizer measured d from the reaction point; now the program measures the distance d from the edge of the support, for both end supports and interior supports.
Output
Bearing and Reactions Table
Title
If the full detailed bearing results are shown, it is now called
Maximum Reactions (unit), Bearing Capacities (unit), and Bearing Lengths (unit).
All the section titles in the output, e.g. LOADS, are to be changed to title case from all caps.
Capacity
The program shows the factored bearing for both the beam and the support. This capacity is in the same units as the bearing reaction, that is, if the user has selected Express reactions as UDL, it is in plf, using the joist spacing to convert.
Anal/Des
This is the lowest value of factored reaction / factored capacity for any load combination, for both the Beam and Support capacity.
It now says “Joist” if it is a joist member.
Load Combination
This applies to the critical load combination used for the Anal/Des
Length
This is the designed or user-input bearing length along the main member, taking into account user settings for rounding bearing lengths.
If the program uses the minimum bearing length from the Design Settings, an asterisk appears along with the following note below the table, using ½” as an example input:
*Minimum bearing length setting used: ½” for end supports [ and ½” for exterior supports]
Min reqid
In most cases, the minimum required bearing length for capacity to equal reaction.
Exception: If the design setting that indicates you use the absolute minimum allowed bearing (also input in the design settings) to calculate design span, and that value is greater than the calculated minimum, it appears here. An asterisk is placed by the number, referring to the same note indicated above for Length, as shown below
Width
This line is shown only if one or more of the bearing widths are not the same as the main member width. For those supports that have “Same as beam” selected as the bearing width the output shows the actual width of beam
KB
This is the bearing factor KB for the main member bearing length.
KB min
This is the bearing factor Cb applied to the minimum bearing length, which can be different than the designed bearing length.
KB support
This is the bearing bearing factor Cb applied to the main member bearing width for beams and sill plates that are assumed to run perpendicular to the main member.
fc/fcp sup
This is the fcp value for support beams, sill plates and walls
Non-wood supports
For “Hanger” and “Other non-wood” supports, the program prints a dash in place of capacity, Cb factor, and Anal/Des for supports
Point load near supports
If CSA O86 5.5.7.3 for point loads bear supports governs, it is indicated by a caret (^) appearing by the anal/design, length, and min req’d fields, and the a note under the table indicating so.
Show detailed bearing results setting
A checkbox setting has been added to the Settings Page under Preferences | Beam and Column Mode Options named
Include detailed bearing results
If unchecked then, in the Bearing subsection of he Reactions and Bearing Table, only the length, width ( if applicable) and minimum length is output.
If checked, the bearing subsection contains additional information including capacity of beam and supports, the load combination number, and Cb factors.
Minimum bearing Length Note
When the supporting member governs, a note with two asterisks appears saying
Minumum bearing length governed by required width of the supporting member.
This note appears only when “unknown’ is chosen for bearing length.
Materials specification
The materials for the supports are shown below the main member materials as a list within a sentence below the main material specification.
It shows the specific material like Glulam Unbalanced or Lumber n-ply rather than the general class of material like Lumber or Glulam.
Warning message
If any of the bearing capacities are greater than resistance, i.e. the Anal/Design ratio is greater than 1.005, the program displays a bearing warning along with the other design criterion messages.