Section R602.10.4 Length of braced panels. “each braced wall panel shall be at least 48 inches (1219 mm) in length, covering a minimum of three stud spaces where studs are spaced 16 inches (406 mm) on center and covering a minimum of two stud spaces where studs are spaced 24 inches (610mm)on center.” TABLE R602.10.1 WALL BRACING requires the wall bracing to be at the ends and at least every 25 feet on center.
In a continuous wood structural panel sheathed wall TABLE R602.10.5 reduces the length requirement of the wall bracing to as little as 24 inches for a 8 foot wall and 30 inches for a 10 foot wall depending on the height of the opening next to the wall segment. These shorter segment will not meet the requirement of a shearwall’s height to length ratio (typically 30%). SSTD 10-99 requires the corners to be at least 27 inches for and 8 foot wall and 34 inches for a 10 foot wall, these segment can be considered shearwall segments.
Section R602.10.6 Alternate braced wall panels. allows for reduced wall segments of 32 inches under special conditions for 1 and 2 story buildings. This provision requires additional holddowns and additional foundation reinforcement.
APA has a prescriptive design which takes the continuous wood structural panel segments down to 16 inches as a portal framed opening. Click here for the link to the publications.