San Francisco has released its Tall Buildings Strategy that outlines plans for better seismic resiliency for high-rise buildings.
A city building inventory shows that 156 buildings—either existing or under construction—are taller than 240 feet. One hundred of those were built prior to modern seismic code implementation.
A report by the non-profit Applied Technology Council recommends that the city develop regulations to address foundation and geotechnical issues like those plaguing Millennium Tower. That 58-story structure has started sinking and tilting.
The report suggests that city building codes be revised to mandate lower thresholds for seismic evaluations and retrofits when existing buildings undergo renovations, or when they are sold or re-leased. In addition, the report recommends that steel-frame buildings be inspected for weld damage that might have been caused by the 1989 Loma Prieta earthquake.