185 Berry Street
San Francisco, CA
This project involved an innovative, multi-story addition to the top of the Berry Building. Project objectives were met to expand the existing three story, 216,000 sf building by 150,000 sf and build two new stories, while causing minimal disruption to the bio-science laboratories below operated by University of California at San Francisco (UCSF). The two new stories were constructed on seismic isolation bearings over the roof of the existing structure, a concept that has never been implemented in any building in the United States. The technique enabled the new construction to perform like a mass damper, which not only permitted the new space to be constructed without requiring structural upgrade, but also improved its seismic performance capability. Most importantly, it eliminated the need for a major seismic retrofit of the occupied building underneath.