You should now understand how to use the IBC and UBC Allowable Shear Tables for shear walls.   Most of the parameters (nail size, sheathing thickness, etc.) from the allowable shear tables are relatively straightforward to understand.  The allowable unit shear deserves some attention however.  Unit shear (v) is the resultant lateral load (R) from the horizontal diaphragm, divided by the sum of the lengths of the full-height sheathing segments.  

Single Panel Shear Wall

Multi-panel Shear Wall (segmented)

v = R / b

v = R / (b₁ + b₂)

 
          From the illustration above, it can be seen that if a door is placed in the shear wall, the unit shear (v) increases.  The same is true for windows or other openings in the shear wall.  It can also be shown that a longer shear wall will have a lower unit shear than a shorter one, thus permitting the use of thinner sheathing and fewer (or smaller) nails. 
 

Introduction,  Load Path, Segmented Design Method, UBC Design Table,  Dimension Ratios, Chord Design, 
 Anchorage, Deflection, Perforated Design Method, Method Comparison, Shearwall Failures