San Francisco Moving To Retrofit Vulnerable High-Rise Towers
On Thursday, San Francisco released an updated list of its vulnerable high-rise buildings, listing more than 150 of its tallest structures that may need earthquake retrofitting.
As high-rise structures in the area have already begun showing signs of degradation, the updated list is the latest move to make San Francisco seismically safe.
In addition to identifying vulnerable structures, the city is also requesting that any new construction in the area use updated measures to prevent sinking, in addition to making these buildings stronger in order to sustain the back-and-forth shaking of a sizable earthquake.
This a major step for California – while cities like Los Angeles and Santa Monica have also made moves to retrofit at-risk buildings in their areas – this is the first time a major city has begun identifying vulnerable skyscrapers in downtown districts.
“We must act before the next earthquake strikes to ensure the safety of residents, workers and visitors,” said San Francisco City Administrator Naomi Kelly.
California’s earthquake history has shown that many concrete and steel-framed buildings that were built before modern safety codes do not have the reinforcement required to survive a major quake.
“There is no doubt that those older steel frame buildings are far more likely to collapse than their designers anticipated,” Keith Porter, a professor of structural engineering at the University of Colorado, Boulder told the Los Angeles Times. “A collapse of one of these buildings could not only potentially kill many of its own occupants, but also people in nearby buildings.
“This is a problem we have known about for decades,” he added.
California officials have put off examining and retrofitting structures like high-rises because of cost, but hopefully cities like Los Angeles will follow in San Francisco’s steps and start inspecting vulnerable steel-frame buildings in their areas.
According to data from the U.S. Geological Survey, a simulation of a 7.8 earthquake along the San Andreas fault could collapse as many as five high-rise buildings in Los Angeles, and if the quake occurred in the middle of a typical workday, some 5,000 people could be inside these structures.
Now more than ever it’s important to be proactive about earthquake preparation and safety. Julian De La Torre is an expert in Los Angeles foundation inspection, foundation repair and foundation replacement.
Julian’s company, Julian Construction, has inspected over 30,000 structures, working with engineering firms and local departments of building & safety. The company has done more foundation repair and earthquake retrofitting in Los Angeles than any other company in the area over the last five years.