L.A. Researchers Know But Won’t Say Which Buildings Are Vulnerable to Earthquakes – Next City
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L.A. Researchers Know But Won’t Say Which Buildings Are Vulnerable to Earthquakes

A building in San Francisco’s Marina District that suffered from soft-story collapse after the 1989 Loma Prieta earthquake. Credit: J.K. Nakata, United States Geological Survey

If you live in Los Angeles, you may be interested to know that a group of university scientists has compiled a list of concrete buildings vulnerable to collapse in an earthquake. But they aren’t going to tell you where.

The Los Angeles Times reports:

Los Angeles officials have known about the dangers for more than 40 years but have failed to force owners to make their properties safer. The city has even rejected calls to make a list of concrete buildings.

In the absence of city action, university scientists compiled the first comprehensive inventory of potentially dangerous concrete buildings in Los Angeles.

The scientists, however, have declined to make the information public. They said they are willing to share it with L.A. officials, but only if the city requests a copy. The city has not done so, the scientists said.

We can, however, make some educated guesses as to where these vulnerable concrete buildings are — namely, any erected before 1976, “when city codes started requiring more steel rebar,” according to the piece. Another worrisome class of buildings are those made of wood and vulnerable to so-called “soft story collapse.”

“Many apartments and condos can collapse in earthquakes because they have parking, ‘tuck-under’ parking or open commercial space on the first floor,” J. Perkins, earthquake and hazards program manager for the Association of Bay Area Governments, wrote back in 2005, “making this story ‘weak’ or ‘soft’ and likely to lean or even fall over in earthquakes.”

“Soft-story apartment and condo buildings were responsible for about two-thirds of the 46,000 uninhabitable housing units in the Northridge earthquake,” Perkins wrote, referring to the 6.7-magnitude quake that rocked the San Fernando Valley, 20 miles northwest of downtown Los Angeles, in 1994.

He suggested a menu of policies to encourage retrofits, from allowing vulnerable lower-level parking to be converted to more lucrative space, to tax subsidies, to rent control breaks for landlords to undergo retrofits.

Mandatory retrofitting of soft story buildings didn’t happen after the Northridge quake, but back in August L.A. Councilmember Tom LaBonge proposed drawing up a list — this one to actually be released to the public — of those vulnerable to collapse. But doing something about these buildings is a lot tougher than just identifying them.

“If San Francisco is any indication, Los Angeles may have a long road ahead,” the Times reported last week. “The city began to focus on soft-story buildings after many of them collapsed in the Marina district during the 1989 Loma Prieta earthquake. The regulations were finally passed 24 years later.”

The Works is made possible with the support of the Surdna Foundation.

Stephen J. Smith is a reporter based in New York. He has written about transportation, infrastructure and real estate for a variety of publications including New York Yimby, where he is currently an editor, Next City, City Lab and the New York Observer.

Tags: infrastructurelos angelesthe worksdisaster planning