Section 511C — SPECIAL PROCEDURE

511C.7 Out-of-Plane Forces – Unreinforced Masonry Walls.

San Francisco Building Inspection Commission Codes · 2022 edition · ingested 2026-07-08 · San Francisco

511C.7 Out-of-Plane Forces – Unreinforced Masonry Walls.

511C.7.1 Allowable unreinforced masonry wall height-to-thickness ratios. The provisions of Section 510C.2 are applicable except the allowable height-to-thickness ratios given in Table 5C-B shall be determined from Figure 5C-1 as follows:

  1. In Region 1, height-to-thickness ratios for buildings with crosswalls may be used if qualifying crosswalls are present in all stories.

  2. In Region 2, height-to-thickness ratios for buildings with crosswalls may be used whether or not qualifying crosswalls are present.

  3. In Region 3, height-to-thickness ratios for “all other buildings” shall be used whether or not qualifying crosswalls are present.

511C.7.2 Walls with diaphragms in different regions. When diaphragms above and below the wall under consideration have demand-capacity ratios in different regions of Figure 5C-1, the lesser height-to-thickness ratio shall be used.

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