How Much Is a Safe Building Worth?
Posted July 6, 2018 9:42 a.m. EDT
How safe will your building be in an earthquake? A bill in the California Legislature, AB 2681, would require cities to create inventories of potentially vulnerable buildings. It has passed through seven committees and is now in the Senate Appropriations Committee, where it faces uncertain passage for budget reasons. The bill would create extra work — and costs — for local municipal building departments.
Assemblymen Adrin Nazarian, who introduced the bill, says the cost of identifying weak buildings is worth it.
“When the ground starts shaking, you can either pray your building is safe or know your building is seismically safe,” Nazarian said by email.
Often the public is not informed that a building is not to code until after a problem has been fixed. Last month The New York Times published an article about high-rise buildings in San Francisco with a seismic flaw that make them potentially vulnerable to collapse in a very big earthquake.
The owners of one of the buildings, a 20-story building at 100 Van Ness St., reached out to disclose that the building had undergone a comprehensive renovation that brought the building up to code and thus made it more seismically safe.
Kevin L. Menninger, the chief engineer of the project, calculated that before the renovation the building was around 15 percent weaker than required by the code. The steel skeleton was too flexible and vulnerable to moving from side to side during a large earthquake, which in extreme cases can lead to collapse.
The solution was to significantly lighten the building, replacing the concrete cladding with glass and lopping off a heavy penthouse. Changes to the facade alone, which took a year, cost more than $20 million.
Marc Babsin, a principal at Emerald Fund, the building’s co-owner, said they had no choice but to seismically retrofit the building — they were changing the building from office to residential use and thus needed to meet current standards. But Babsin says he’s skeptical other owners would voluntarily go through the same process.
“Unless you’re required to do it by the building code it’s hard to imagine an owner/operator going through the expense of doing it — moving people out, giving up rent, breaking leases,” Babsin said. “It’s quite an undertaking.”