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Identical Materials and Construction on Shear Line

If this setting is selected, changes made to any of the the material properties of any shear wall are also applied to the rest of the shear walls on the same shear line, that is, all shear walls on a shear line must have an identical material specification,. If it is not checked, only the class of material, that is, wood structural panels (WSP), gypsum-based materials, fiberboard, or lumber siding, must be the same on all walls on the shear line to satisfy SDPWS 4.3.5.5. .

Although not SDPWS, forcing materials to be identical has advantages in terms of processing time and generating practical designs.

If this setting is checked, the program designs for unknown parameters using the critical segment on the shear line for design. If it is not checked, all the walls are designed separately.

By default, this setting is unchecked, that is, non-identical materials along a line are allowed.

Capacity-based vs. Deflection-based Force Distribution

When using capacity-based force distribution, if this setting is checked, a new design can redistribute forces along the line, and an extra design iteration is needed to stabilize the distribution of shear line forces on the line. Deflection-based distribution requires iterative design regardless of whether identical materials are specified, however non-identical materials can still increase design processing time and the number of iterations needed.

Walls of Same Material Class

The following applies to when this box is not checked:

SDPWS Commentary C4.3.5.5 clarifies what is meant by "same materials and construction" along a shear line. The. following classes of materials must be the same, but details such as the sheathing thickness and nailing patterns do not have to be identical.

Note that when all walls on the shear line have to be identical, they are necessarily of the same design group, but when they are only required to be of the same material class, there can be walls from different design groups on the shear line. If the material class is changed such that all wall groups on the line are of that class, then walls of the same group(s) on other lines also change. In this way, a change to material type can propagate through the structure.

Note too that the requirement of having the same material class is applied to the wall as a whole, not each side independently. So a wall with WSP on one side and nothing on the other is of the same class as one with WSP on both sides. But a wall with WSP on one side and gypsum wallboard on the other is of a different class.

See Also

Design Procedures

Wind Load Design Procedure

Design Options