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A new page has been added to the Settings input for hold-down data that apply to all hold-down locations in the structure.
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.
Hold-down forces
A new group box is added to include options affect the generation of hold-down forces from shearline forces on segments.
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 shearwall 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.
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.
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.
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.
Displacement
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.
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.
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.
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.
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 shearwall. 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.
Other (miscuts, gaps, etc.)
Additional sources of vertical shearwall 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
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.