5.4 Unreinforced Masonry Shear Walls
The building satisfies the Quick Check of the shearing stress in the unreinforced masonry shear walls.
Generate the lateral loads using the Quick Check procedure of Section 18.104.22.168. The allowable stress (on the gross area) for solid brick masonry is 10 psi; for hollow unit masonry, 6 psi; and for grouted block masonry, 12.5 psi. If vavg is greater than the allowable stress, an Alternative Analysis of the structure shall be performed, or the building shall be placed in SPC 1.
Filled collar joints of multiwythe masonry walls have negligible voids.
The deficiency is in the lay-up of the wall that left voids between the wythes. Investigate the lay-up. This can be done when masonry units are removed for strength tests. If voids are present, report this condition as a deficiency.
The height/thickness ratio of the wall panels is as follows:
- One-story building hw / t < 15
- Top story hw / t < 9
- Other stories hw / t < 13
The deficiency is in the out-of-plane strength of the wall. Check the out-of-plane demand using the procedure for parts and portions of a building given in Section 2.4.6.