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 | Sep 17, 2019
California will enact rent cap bill limiting rent increases to 5% plus inflation
Applies to apartments built at least 15 years ago.
Codes and Standards | Sep 17, 2019
Zero energy buildings can be constructed with no added upfront cost
ROI can be realized in as little as one year.
Codes and Standards | Sep 13, 2019
Researchers use U. of Arkansas buildings as testbed for CLT panels
Investigation could influence future use of the materials.
Codes and Standards | Sep 13, 2019
At least 30 U.S. cities have adopted stricter building energy codes since 2017
Some followed their states in implementing more robust standards.
Codes and Standards | Sep 12, 2019
Illinois law sets maximum retainage on private projects
The change is expected to give contractors bigger checks earlier in project timeline.
Codes and Standards | Sep 10, 2019
Retreat may be the best option for some coastal communities in face of sea level rise
A new study makes the case for relocating in a "strategic, managed" manner.
Codes and Standards | Sep 9, 2019
Free app calculates maximum allowable heights and areas for buildings
A free app that calculates the maximum allowable heights and areas for buildings of various occupancy classifications and types of construction has been released.
Codes and Standards | Sep 6, 2019
Standard for assessing frame deflection using one component polyurethane foams updated
The standard offers guidance when installing fenestration products.
Codes and Standards | Aug 29, 2019
The high cost of gridlock: $166 billion per year
Growing economy means more jobs, more cars, more hours stuck in traffic.
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.
