Thirty-nine high rises in San Francisco are at risk of collapse in a major earthquake, according to a new study by the U.S. Geological Service (USGS).
The vulnerable buildings (known as welded steel moment-frame buildings) were constructed by using a flawed technique to weld columns and beams together. This technique was found to be less resilient to seismic activity after the 1994 Northridge earthquake in Los Angeles where critical joints were damaged in several buildings that had been welded.
The building code was revised in the mid-1980s to require more stiffness, and then again in the mid-1990s to correct the defective welding technique. San Francisco outlawed the technique in1994 after damage from the Northridge quake on high rises was discovered. The list of vulnerable structures includes the former Bank of America building, the headquarters of Pacific Gas and Electric, three hotels, and the Salesforce West tower.
San Francisco has offered incentives to repair at-risk buildings. In 2009, the city expedited permits and agreed to waive fees for so-called “soft-story buildings” that have garages or windows on the bottom floor.
Related Stories
Codes and Standards | Mar 6, 2020
Design firms creating plans to re-imagine D.C.’s tidal basin
Area including National Mall is facing increased flood risk.
Codes and Standards | Mar 5, 2020
France to mandate all new public buildings be 50% timber or other natural materials
Measure would go into effect by 2022.
Codes and Standards | Mar 4, 2020
American Concrete Institute and Precast/Prestressed Concrete Institute expand partnership
Will collaborate on new code requirements.
Codes and Standards | Mar 3, 2020
Wallcoverings industry releases product scorecards concerning sustainability
Tool adds more transparency to certification.
Codes and Standards | Feb 28, 2020
Bay Area communities struggle with what to do about rising sea level
Policies include sea walls, levies, and relocation.
Codes and Standards | Feb 27, 2020
Cell phones present a safety hazard at job sites
Use of ear buds, headphones banned by some contractors.
Codes and Standards | Feb 26, 2020
American Concrete Institute releases 2020 codes, specifications, and practices
ACI Collection features guidance on structural concrete construction and rehabilitation.
Codes and Standards | Feb 25, 2020
New ISO standard for optimizing building use and reusing and recycling components released
Aim is to realize full potential value of a building throughout its life cycle.
Codes and Standards | Feb 21, 2020
Architects push back on proposed uniform design mandate for federal architecture
AIA speaks out against measure.
Codes and Standards | Feb 20, 2020
City-owned buildings to go carbon-free in Los Angeles
Mayor commits to goal for new and extensively renovated structures.