Monday, November 14, 2011

Unreinforced Masonry Wall from 1965


We have a renovation project in a low seismic area (SDC B). The 27-foot-tall exterior walls are unreinforced ungrouted (hollow) 8" concrete masonry interwoven with 4" brick face shells (12" nominal thickness). The occupancy is changing from Category 2 to Category 3 (>300 people in one space), so we are obligated to check the existing walls. However, due to the height, I cannot make them work using the "unreinforced masonry" provisions in MSJC Section 2.2.

Does anyone have any idea how the original engineer may have made these walls work in 1965? It strikes me that the code provisions for unreinforced masonry have probably not changed much in 50 years (seismic regions excepted). The owner is very sensitive to budget (who isn't these days?), so I'd like to find a way around an costly retrofit.

Thanks for your input,
Dan Popp, S.E.