Pounding of San Francisco–Type Soft-Story Midblock Buildings

Presented is a study into the effects of pounding on the collapse performance of midblock wood-frame soft-story buildings. This study analyzed various pounding situations and found that it can change the collapse risk when compared to the risk of the same building having no adjacent buildings (no-pounding). Key factors include relative building strengths, weights, and separation (gap) distances. When the buildings had similar strengths, it was found that the risk was about the same as that for no-pounding, independent of building relative weights and/or gap size. When the strengths varied, it was found that pounding could change the risk of certain buildings. The risk increased in the stronger and decreased in the weaker buildings, and the risk was biased toward the no-pounding risk of the heavier buildings. The risk generally increased with larger building separation distances, but there were exceptions.