Shear Wall Design
There are two design methodologies
used for shear walls:
Segmented Design and Perforated Design. The majority of this
tutorial concentrates on the traditional segmented shear wall (SSW) design approach. An introduction to the
approach and its benefits
will be presented later in
Shear Wall Design (SSW) is the traditional design method that has
been used for many years. In the SSW method, walls are divided
into segments of full-height sheathing. These segments are
typically separated by openings in the wall such as doors and windows.
The lengths of each full-height sheathing segment (bi) are summed together,
resulting in a conservative estimate of the length of the wall that will resist shear forces.
The full-height segments are then designed
to resist the applied loads. Hold-down connectors (HD) are required at the bottom corners of
each segment to prevent each
segment from overturning.
The following illustrations depict a typical shear wall.
Figure 1 shows that the wall is made up of six sheathing panels,
typically plywood or oriented strand board (OSB), that have been mounted vertically to the
framing members. Holes have been framed into the wall to accommodate a
window and a door. This wall geometry will be used several times
throughout this tutorial.
|Figure 2 illustrates the shear wall divided into full-height sheathing segments, shown in green. Only the full-height sheathing segments are assumed to provide resistance to lateral loads. The sheathing grade and thickness and the nail size and spacing determine the shear capacity per foot of length of the full-height segments. IBC Table 2306.4.1 and UBC Table 23-II-I-1 relate these variables so that designers can determine the shear capacity (v) in units of lb/ft (plf) of the full-height segments. The design shear capacity, V, is found using the following equation:|
V = v Sbi
|Topics of this module include:|
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