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 | Aug 29, 2019
Industry leaders ask for government help as trades shortage worsens
AGC asks for more funding for education and increased immigration to fill gaps.
Codes and Standards | Aug 29, 2019
Code-conforming wood design guide available
The guide summarizes provisions for the use of wood and wood products in the 2018 IBC.
Codes and Standards | Aug 29, 2019
LEED residential market up 19% since 2017
The U.S. Green Building Council says that the LEED residential market has grown 19% since 2017. Nearly 500,000 single family, multifamily, and affordable housing units have been certified globally.
Codes and Standards | Aug 27, 2019
Slower speed limits in urban areas offer multiple benefits
Improved safety, better adoption of electric scooters and autonomous vehicles are possible if drivers ease off the accelerator.
Codes and Standards | Aug 27, 2019
Renewables creating significant savings for commercial and public facilities
Payback ranges from five to 15 years.
Codes and Standards | Aug 27, 2019
Oregon rescinds tsunami-zone construction ban
Other states have no ban, but have strengthened building codes for tidal wave resilience.
Urban Planning | Aug 27, 2019
Pop-up parks revitalize empty lots
Pop-up parks that provide instant open areas for public use and programming can revitalize under-utilized spaces and add vibrancy to neighborhoods.
Codes and Standards | Aug 22, 2019
Texas flood prevention initiative would create nation’s most ambitious barrier system
Plan including sand dunes and mechanical barriers would cost as much as $32 billion.
Codes and Standards | Aug 22, 2019
Multimedia app identifies construction hazards
Researchers say program will reduce injuries, save lives.
Codes and Standards | Aug 22, 2019
Cities take action to keep cool as climate heats up
Initiatives include cool streets, cool roofs, and broader urban tree canopy.
