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Force transfer walls are subject to the following limitations:
Opening Configuration
There must be least one foot of sheathing above and below each opening, to allow shear forces to develop in opening piers. A consequence is that walls with doors cannot be designed as force transfer walls. One solution to this situation is to create a non-shearwall for the door.
Pier length
As per SDWPS 4.3.5.2.(1), the length of the wall piers (distance between openings or distance between an opening and the wall end), must be 2’ or greater. According to advice we received from FTAO researchers, this limitation has been applied to unblocked walls only; for blocked walls the piers must be 18" or longer.
Maximum Pier Aspect Ratio
Refer also to Aspect Ratio Limits and Factor.
Full-height End Segments
As per SDWPS 4.3.5.2.(2), a full height segment must be at each end of the wall, that is,a force-transfer wall cannot start at an opening.
Gypsum Materials
As the research and testing on force-transfer walls has been restricted to wood structural panels, the contribution of gypsum wallboard and plaster materials is ignored in calculating design strength and deflection of force-transfer walls, regardless of what is set in the Ignore contribution of... Design setting.