Preparing for the Big OneBay Area cities lag in making housing quake-safe
Many public buildings in Bay Area cities have been retrofitted to make them more earthquake-resistant; most of the two types of private homes which are especially vulnerable to damage by tremors — wood-frame, “soft-story” buildings and concrete-frame structures that lack sufficient steel reinforcement — have not yet been retrofitted
In the twenty years since the Loma Prieta earthquake, some of the Bay Area’s most dangerous schools, roadways, and buildings have been shored up. While hospitals have a long way to go, most have plans to undergo retrofitting.
San Francisco Chronicle’s Robert Selna writes that when it comes to housing — where people spend most of their time — many Bay Area cities have done little to prepare for a major temblor that scientists say has a 62 percent chance of striking the region in the next thirty years.
Selna writes that earthquake engineers say that ignoring the homes’ seismic danger is particularly risky because a high percentage of residents live in housing constructed before the mid-1970s, when building codes were made stricter. If the most susceptible buildings are not retrofitted, thousands of residents could be killed and scores more displaced by a major quake, stretching emergency shelter and social services to a breaking point, experts say.
“We have been retrofitting public infrastructure, but in the Bay Area and California, we have done a miserable job of retrofitting where we live,” said Peter Yanev, a seismic engineer and author who sits on engineering advisory councils at UC Berkeley and the Massachusetts Institute of Technology. “In San Francisco, there are hundreds and hundreds of buildings that are not retrofitted, and they are a risk to people’s lives.”
Other experts say it makes some sense that officials largely have ignored the potential danger presented by shaky housing. Government mandates instead have focused on critical institutions as well as unreinforced brick buildings, which cause the most deaths in earthquakes worldwide.
“On the one hand, we’ve dealt with these killer buildings (made of unreinforced masonry) and required owners to retrofit them so they don’t kill anyone, and we’ve come up with really high standards for hospitals, but then there’s everything in the middle,” said David Bonowitz, a local earthquake engineer and member of a citizen committee that has advised San Francisco on seismic safety.
Under a statewide edict, most cities have required owners of unreinforced masonry buildings to retrofit their structures. In such buildings, masonry serves as the frame as opposed to wood or steel, which is much safer. In San Francisco, 90 percent of the city’s 1,700 risky brick buildings have been fixed.
San Francisco and several other Bay Area
