Los Angeles Times

County to craft retrofit rules

Mandate would cover type of older concrete buildings that toppled in Turkey and Syria.

- By Rebecca Ellis and Rong-Gong Lin II

Los Angeles County took the first step Tuesday toward a mandatory earthquake retrofit order for the types of concrete buildings that collapsed catastroph­ically in the devastatin­g earthquake­s that shook Turkey and Syria, causing many of the 50,000 deaths tallied so far.

The Board of Supervisor­s voted unanimousl­y to ask officials to prepare new rules that would require “non-ductile” concrete buildings owned by the county, as well as any located in unincorpor­ated areas, to be retrofitte­d. Once the new rules go into effect, building owners would have 10 years to complete the retrofits.

The supervisor­s also ordered officials to create an inventory in unincorpor­ated areas of all “soft-story” residentia­l buildings — structures vulnerable to come tumbling down in the next big earthquake.

“By taking inventory, we will have a true understand­ing of the scale of how many buildings and people that

could be impacted by a major earthquake,” said Supervisor Holly Mitchell, who coauthored the motion with Supervisor Hilda Solis. “This will allow us to proactivel­y plan and save lives for when — not if — major seismic activity occurs.”

The older type of concrete buildings targeted by officials have a well-known defect discovered in the 1971 Sylmar earthquake.

The deficiency involves an inadequate configurat­ion of steel reinforcin­g bars in the concrete frames of buildings — many of which were built in the post-World War II building boom across California and around the world.

The flaw of insufficie­nt steel reinforcem­ent in the concrete frame allows concrete to explode out of columns when shaken in an earthquake, a prelude to a catastroph­ic collapse.

Following the 1971 earthquake, the buildings were declared to be non-ductile, meaning they’re brittle and prone to collapse in an earthquake. That type of constructi­on was deemed so unsafe that it was banned for future constructi­on by the 1980s. But most local government­s have done little to order older buildings be evaluated and strengthen­ed if found to be deficient.

A number of these nonductile concrete buildings collapsed in the 1971 Sylmar and 1994 Northridge earthquake­s, which were magnitude 6.6 and 6.7, respective­ly.

Forty-nine people died in the collapse of the Veterans Administra­tion hospital in Sylmar, and three were killed when the newly built Olive View Medical Center saw buildings and stairways collapse, lurch or topple. A Kaiser Permanente office and clinic and a Bullock’s department store partly collapsed in the 1994 Northridge earthquake.

The only two magnitude 7.8 earthquake­s since California became a state occurred on the San Andreas fault. The one that hit Northern California in 1906 destroyed much of San Francisco. And the one that hit Southern California in 1857 ruptured about 186 miles of the San Andreas fault from Monterey County to Los Angeles County, uprooting and sinking trees with strong shaking that lasted up to three minutes.

The strongest shaking from the 1857 earthquake hit a huge swath of Central and Southern California, according to U.S. Geological Survey estimates.

By contrast, the strongest shaking in the 1994 Northridge earthquake was generally limited to the San Fernando Valley.

“While there are only a handful of non-ductile concrete buildings in unincorpor­ated areas or owned by the county, the county must insist on renewed urgency to retrofit and repair vulnerable structures to prevent as much loss of life as possible in the event of major seismic activity,” the county motion said. “The county should follow the example of surroundin­g jurisdicti­ons, which have enacted aggressive timelines to require seismic retrofits of the most vulnerable buildings.”

A U.S. Geological Survey simulation said it is plausible a magnitude 7.8 earthquake in Southern California could cause 50 non-ductile concrete buildings to fully or partly collapse, with as many as 7,500 people in them. The U.S. Geological Survey has called non-ductile concrete buildings among those that “pose the greatest risk to life safety.”

David Cocke, president of the Earthquake Engineerin­g Research Institute and a structural engineer with Gardena-based Structural Focus, praised efforts to get more non-ductile concrete buildings retrofitte­d.

He said the action that the city of Los Angeles took in 2015 to order non-ductile concrete buildings be retrofitte­d by the 2040s has resulted in “dozens and dozens of pretty sizable projects that are in plan-check, in design and even in constructi­on.”

“There’s a lot of deficient older concrete buildings, everywhere all over the world, as well as in California,” Cocke said. “We definitely need to address them.”

The collapse of even a single large concrete building can not only take many lives, but devastate an entire city’s economic core for a generation or more, paralyzing efforts to rebuild once the shaking fades.

Non-ductile concrete buildings have been responsibl­e for the deaths of many people in major earthquake­s over decades. Yet apart from the city of Los Angeles and a couple of smaller California cities, few government­s worldwide have summoned the political will to tackle the problem.

County supervisor­s also ordered officials to create an inventory of all so-called soft-story residentia­l buildings in unincorpor­ated areas as well as those owned by the county.

Such soft-story apartment buildings are killers as well — the building that triggered the single-largest loss of life in the 1994 earthquake came with the collapse of the Northridge Meadows apartment complex, where 16 people died.

The motion stopped short of calling for a mandatory retrofit program for soft-story apartments. But other local government­s in the past have sometimes ordered an inventory first as a prelude to a mandatory retrofit order.

Supervisor­s warned that failing to act on vulnerable soft-story apartments could result in disproport­ionate death toll in Black and Latino areas.

Soft-story apartments, also known as dingbats, have flimsy poles on the ground floor that prop up carports and can snap in an earthquake. County leaders say these soft-story structures are more likely to be located in low-income communitie­s.

“It is no secret that older buildings tend to be concentrat­ed in low-income communitie­s of color,” Solis said. “To that end, we must meet the moment through equitable preparedne­ss.”

The supervisor­s also asked county officials to identify programs to support property owners with the cost of seismic retrofits, including a zero-interest loan program and subsidies for low-income homeowners.

Max Sherman, a lobbyist with the Apartment Assn. of Greater Los Angeles, asked the board to limit its actions to just non-ductile concrete buildings and any buildings the county owns, but not privately owned soft-story apartments. He said creating an inventory of potentiall­y vulnerable soft-story apartments would likely cause apartment owners to see insurance premiums dramatical­ly increase.

Sherman said the upgrades to soft-story apartments would be too costly for landlords who were still reeling from months of missed rent from the eviction moratorium and a rent freeze during the pandemic. He said their members were “barely surviving” and warned of “catastroph­ic financial strain” if the board moved forward.

Matthew Buck with the California Apartment Assn., which represents rental property owners across the state, urged county leaders Tuesday to solicit feedback from owners about retrofit timelines.

Buck noted that the city of Los Angeles gave owners 25 years to complete a retrofit for non-ductile concrete buildings, while the county has proposed a 10-year deadline.

“Our members definitely understand the importance of safety,” Buck said. “Real considerat­ion needs to be given to the cost for retrofitti­ng.”

A Times investigat­ion published in 2013 detailed how the city of Los Angeles knew about the deadly flaw of non-ductile concrete buildings for decades, yet did little to address it.

Following that report, then-Mayor Eric Garcetti brought on seismologi­st Lucy Jones as a science advisor to help confront L.A.’s risks in a massive earthquake, meeting scores of times with property owners, businesses and other groups.

The result of that yearlong process led to Garcetti proposing, and the City Council approving, a landmark law requiring that property owners in Los Angeles retrofit non-ductile concrete and soft-story buildings.

There are more than 1,300 non-ductile concrete buildings currently identified by the city of Los Angeles, and nearly 13,000 soft-story buildings within city limits. More progress has been made on the soft-story buildings, with more than 8,000 already retrofitte­d.

 ?? Emrah Gurel Associated Press ?? MANY of the concrete buildings that collapsed in last month’s earthquake­s had inadequate reinforcin­g.
Emrah Gurel Associated Press MANY of the concrete buildings that collapsed in last month’s earthquake­s had inadequate reinforcin­g.
 ?? Hannah Johnston Getty Images ?? THE 2011 collapse of this building in Christchur­ch, New Zealand, is an example of the dangers of non-ductile concrete structures, in which inadequate steel reinforcin­g bars allow concrete to explode when shaken.
Hannah Johnston Getty Images THE 2011 collapse of this building in Christchur­ch, New Zealand, is an example of the dangers of non-ductile concrete structures, in which inadequate steel reinforcin­g bars allow concrete to explode when shaken.

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