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Overview of Load and Force Distribution and Shear Wall Design Process
WoodWorks® Shearwalls distributes seismic and wind loads applied to building faces to shear lines consisting of walls separated by no more than a specified offset. The loads are converted to shear line forces by the rigid diaphragm method and by the flexible diaphragm method. The shear line forces then accumulate vertically from building level to building level.
The shear line forces are used to calculate secondary forces such as the design shear, holddown forces, and dragstrut forces at the appropriate locations. Vertical dead and wind uplift loads are also considered in the calculation of hold-down forces. Hold-down forces are then transferred vertically from building level to building level.
Design shear forces and hold-down forces are used to calculate deflections, which are then used to iteratively redistribute the forces within shear lines.
WoodWorks Shearwalls selects shear walls with the factored capacity to resist the unit design shear forces (i.e, force per unit length) and to withstand out-of-plane wind loads perpendicular to the wall line. The program searches its design tables for suitable wall assemblies for the wind load case, the seismic load case, and for flexible diaphragm and rigid diaphragm design cases. The program is able to design wall for the most severe of these cases, and to impose the same wall design in wall groups that you specify.
The CSA O86-19, CSA O86-14 or CSA O86-09 procedures are used.
The results of the design are shown in Shear Design table (in-plane wind and seismic) and Component and Cladding (C&C) table (in-plane wind) of the Design Results. There are also tables showing loads, shear wall and shear line dimensions, sheathing and framing materials, deflections, hold-down displacements, hold-down design, and collector forces.
The shear and C&C results, wall materials and dimensions, segment and pier aspect ratios, and all of the forces acting upon the shear wall are also shown in the drawing of the shear walls in Elevation view.
A Design Summary page in the Design Results lists any failed walls or hold-down devices. Failed walls are also indicated in Elevation view, and are shown in red in Plan view.
Many of the design results are reported on a shear line by shear line basis. A change in building structure that changes the configuration of shear lines obliterates these design results, so a new design run is necessary.