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Crosswalls shall meet the requirements of this section.
A crosswall is a wood-framed wall sheathed with any of the materials described in Table A1-D or A1-E or other system as defined in Section A111.3.5. Crosswalls shall be spaced no more than 40 feet (12 192 mm) on center measured perpendicular to the direction of consideration, and shall be placed in each story of the building. Crosswalls shall extend the full story height between diaphragms.
- Crosswalls need not be provided at all levels when used in accordance with Section A111.4.2, Item 4.
- Existing crosswalls need not be continuous below a wood diaphragm at or within 4 feet (1219 mm) of grade, provided:
- Shear connections and anchorage requirements of Section A111.5 are satisfied at all edges of the diaphragm.
- Crosswalls with total shear capacity of 0.5SD1ΣWd interconnect the diaphragm to the foundation.
- The demand-capacity ratio of the diaphragm between the crosswalls that are continuous to their foundations does not exceed 2.5, calculated as follows:
Within any 40 feet (12 192 mm) measured along the span of the diaphragm, the sum of the crosswall shear capacities shall be at least 30 percent of the diaphragm shear capacity of the strongest diaphragm at or above the level under consideration.
Existing crosswalls shall have a maximum height-to-length ratio between openings of 1.5 to 1. Existing crosswall connections to diaphragms need not be investigated as long as the crosswall extends to the framing of the diaphragms above and below.
New crosswall connections to the diaphragm shall develop the crosswall shear capacity. New crosswalls shall have the capacity to resist an overturning moment equal to the crosswall shear capacity times the story height. Crosswall overturning moments need not be cumulative over more than two stories.
Other systems, such as moment-resisting frames, may be used as crosswalls provided that the yield story drift does not exceed 1 inch (25 mm) in any story.
Related Code Sections
A111.3 Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings, Crosswalls
Crosswalls shall meet the requirements of this section ...
Existing Building Code 2015 of Idaho > A1 Seismic Strengthening Provisions for Unreinforced Masonry Bearing Wall Buildings > A111 Special Procedure > A111.3 Crosswalls