L.A. Tries S.F.’s Retrofit Approach

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Kaiser Permanente’s weak concrete office building in Los Angeles suffered partial collapse in the 1994 Northridge Earthquake. Photo by Gary B. Edstrom, Wikimedia Commons.

Other California cities are following San Francisco’s example to compel owners of vulnerable apartment buildings to make them earthquake safe.

The Los Angeles City Attorney is drafting a law that would force owners to retrofit thousands of buildings whose weak first floors are vulnerable to collapse in a quake. The City of Santa Monica is also following suit. Building officials from both cities have been in direct conversation with policymakers in San Francisco.

“The L.A. project was strongly influenced by what had happened in San Francisco,” U.S. Geological Survey scientist Lucile Jones said in an email. “I met with San Francisco’s chief resilience officer, Patrick Otellini, several times before and during my year with Los Angeles.”

Jones helped Los Angeles Mayor Eric Garcetti conceive his proposed retrofit plan, which will mandate retrofits of the ground floors of soft-story wood-frame buildings with four or more housing units and will require even more extensive work for non-ductile, or unreinforced, concrete buildings.

San Francisco was the first city to mandate retrofits. After trying a voluntary program, the city has embarked on a 30-year timeline to get property owners to strengthen its building stock.

Jones called San Francisco’s “a very bottom-up process,” which started with technical analysis and ended many years later with a drafted law. As the Public Press has reported, San Francisco started studying the vulnerability of local buildings in 1998, and it was not until 2013 that legislators passed the retrofit mandate.

By comparison, Jones said, the approach in Los Angeles was “much more top-down,” driven mostly by the Mayor’s Office and on a quicker timetable. Jones said she and the mayor assumed they had “one shot at promoting resilience.” So they quickly drew up a retrofit plan that included weak concrete buildings as well as wood-frame structures.

“I think it’s likely that, just like L.A. learned something from San Francisco about soft-first-story approaches, San Francisco will study what L.A. did about concrete buildings,” she said.

Los Angeles contains an estimated 13,000 wood-frame soft-story structures and 1,000 built of concrete. To date, San Francisco’s own retrofit program has identified about 5,000 soft-story buildings within its bounds, and the city has tentative plans to strengthen weak concrete buildings in coming years.

A draft of the Los Angeles ordinance is expected to go before the city’s Housing Committee for deliberation this month, said Louis Reyes, communications director for Council Member Gilbert Cedillo, who initiated the legislative process.

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