Infrastructure & Environment

Los Angeles Will Identify the City's Most Earthquake-Vulnerable Apartment Buildings

by | June 16, 2014
 

By Rong-Gong Lin II and Rosanna Xia

Los Angeles Mayor Eric Garcetti signed off on the city's most aggressive action on earthquake safety in nearly three decades, instructing building officials this week to comb the city and identify thousands of apartment buildings vulnerable to collapse in a major temblor.

The survey will focus on wood-frame buildings similar to the Northridge Meadows apartment complex that collapsed and killed 16 people in the magnitude 6.7 earthquake in 1994. Building officials estimate there are at least 5,800 buildings of that type in the city, and an additional 11,690 buildings will need to be inspected to determine whether they should be included on the list.

Garcetti's signing comes a week after he took the issue of earthquake safety to Sacramento, where he lobbied the governor and legislative leaders on the issue of earthquake retrofitting.

In a brief interview earlier this week, Garcetti said it was important for Los Angeles to share its plans on earthquake safety with state officials.

"I said, specifically, we're going to be developing some of our own solutions in Los Angeles, some of our own mandates," Garcetti said in the interview after welcoming the Electronic Entertainment Expo to the Los Angeles Convention Center. "We want to see if the state can step up and help, and vice versa, if anything we're doing can be helpful to the state."

Sharing ideas on earthquake retrofitting is important, he said. "If L.A. develops something, that's great, maybe for our buildings. But too bad if you're right over our border," Garcetti said. "So we're really looking at L.A. inspiring leadership throughout the state."

One example would be making sure that the Edmund G. Brown California Aqueduct can continue to transport water to Southern California after a big earthquake.

"If we're cut off -- because the California Aqueduct is near the epicenter -- for six months from fresh water? That's something you need to consider in any water legislation they're looking at," Garcetti said.

In May, Patrick Otellini, who is in charge of implementing San Francisco's earthquake safety program, told the Los Angeles Times that there has been a close collaboration between Garcetti's office and San Francisco Mayor Ed Lee's staff on trading earthquake safety policy ideas. Last year, San Francisco passed a landmark law that requires the city's wooden apartment buildings to be strengthened. "There's a pretty robust conversation happening between Los Angeles and San Francisco," Otellini said. "I have never seen this much communication before ... establishing quarterly meetings with mayors' staff to compare notes, trying to figure out how we can all get safer through this process."

Having two of California's largest cities talk about earthquake safety "gives us tremendous leverage to look at it on a statewide level," Otellini said.

While San Francisco is well underway in identifying its wooden apartment buildings that are vulnerable to shaking, Los Angeles is starting from scratch.

Until now concerns about costs have stalled Los Angeles' efforts to tackle the issue of retrofitting. Seismic experts and policymakers say a citywide survey to figure out which structures might be vulnerable is a necessary first step.

"It's so key," L.A. City Councilman Tom LaBonge said last month after the City Council backed the motion he introduced about a year ago. "You have to have the data to know how many buildings are like this and where they are. And to give us a kind of road map of what we can do to improve these buildings."

The city has not decided what to do once it compiles the list. The action marks the first in what is expected to be several seismic safety measures at City Hall. Garcetti said earlier this year that he supported some type of mandatory retrofitting of older buildings that have a risk of collapse in a major earthquake. He also said he wanted buildings across Los Angeles to be graded for their seismic safety.

Other elected officials in Los Angeles have sought state backing for tax breaks for owners who retrofit their buildings or funding for cities to implement local earthquake safety programs.

Garcetti has said he would be looking specifically at older concrete buildings and "soft-story" wooden apartments. Soft-story buildings have weak first floors because they are often built over carports and held up with slender columns.

No city data exist to easily identify which structures are wood-framed and soft-story, said Ifa Kashefi, chief of the engineering bureau at the L.A. Department of Building and Safety. The survey would focus on structures built before 1978 with at least two stories and at least five units.

Three people would be hired to work for the building and safety department to create this inventory. The project would take about 18 months, officials said.

In January, Garcetti appointed Lucy Jones, a U.S. Geological Survey seismologist, as his earthquake science advisor and asked her to come up with recommendations on how to get vulnerable wooden and concrete buildings retrofitted. He has also asked her to develop plans to preserve water and telecommunications systems during a Big One.

In October, The Times reported that by the most conservative estimate as many as 50 of the more than 1,000 concrete buildings in the city built before 1976 would collapse in a major earthquake, exposing thousands to injury or death.

(c)2014 the Los Angeles Times

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