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
| Mar 22, 2012
Bill would reintroduce “opt-out” provision in lead paint law
The Lead Exposure Reduction Amendments Act of 2012 (S2148) would restore the "Opt-Out" provision removed from the Environmental Protection Agency's Lead Renovate, Repair and Painting (LRRP) rule in April 2010.
| Mar 15, 2012
New Florida building code establishes flood and storm surge provisions
The new 2010 code establishes minimum design and construction requirements to protect buildings from wind, rain, floods, and storm surges.
| Mar 15, 2012
Illinois city rejects international code due to home sprinkler requirement
Macomb, Illinois aldermen voted to recommend that the city not adopt 2012 international building and residential code standards requiring the installation of overhead sprinkler systems in newly constructed one-family and two-family homes.
| Mar 15, 2012
Tenant advocates propose licensing landlords in New York City
With thousands of New York City rental units posing potential dangers to tenants, city advocates are proposing measures to make landlords improve building safety.
| Mar 15, 2012
Construction industry a big winner in federal small disadvantaged business procurement
Last year, only 5% of federal contract dollars went to small disadvantaged businesses. Construction and facilities support firms were the biggest beneficiaries.
| Mar 15, 2012
ANSI approves new fall protection standards
The American National Standards Institute (ANSI) has approved two American Society of Safety Engineers' (ASSE) standards addressing fall protection.
| Mar 8, 2012
Engineering innovation provides new option for meeting seismic codes in skyscrapers
Two University of Toronto engineers have developed “viscoelastic-energy-dissipating dampers” to replace many of the heavy concrete beams used in tall structures.
| Mar 8, 2012
CSI webinar on building code compliance March 22
A March 22 webinar will provide an overview of a 28-step process during the design of a building to ensure compliance with building codes.
