Tall buildings safety strategy results released for San Francisco

SAN FRANCISCO (KGO) -- A tall buildings study commissioned by the late San Francisco Mayor Ed Lee focused on buildings above 240 feet. Now 16 recommendations are aimed at strengthening the city's seismic safety requirements, promoting earthquake preparedness and enhancing the city's ability to respond to large earthquakes.

"We don't expect to have complete failure of these buildings. Our bigger concern is probably the longer term recovery, can we get people back in their residences and businesses back up," said Mary Ellen Carol, executive director of the Department of Emergency Management.

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A review of more than 150 tall buildings in San Francisco included building a database, cataloging in part the age of the materials used in the buildings.

Stanford University Professor Greg Deierlein is one of the authors of the resulting report.

"Current building codes really just protect or are geared to protect life safety of a building... don't necessarily address recovery," said Deierlein.

Deierlein says 60 to 70 buildings used the same type of steel welds that fractured during the 1994 Northridge Earthquake in Los Angeles.

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"It was due to a combination of design and detailing practices, kind of connection details that were used the weld metals that were used and the welding processes," said Deierlein.

The report suggests San Francisco's tall buildings should be inspected for similar damage that might have gone undetected after the 1989 Loma Prieta Earthquake.

"This is one of the first efforts to really look back and start to address, be proactive about starting to look more carefully at assessing those buildings," said Deierlein.

The study suggests there is a link between the geotechnical aspects of construction and the integrity of tall buildings.

The report compiles best practices in geotechnical engineering and foundation types and discusses acceptable limits of settlement.

The final report will be released in November. The city administrator says her office looks forward to implementing the recommendations.

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