Mayor Eric Garcetti wants buildings across Los Angeles to be graded for their seismic safety as part of an ambitious plan to help residents understand the earthquake risks of their office buildings and apartments.
Garcetti announced what would be the nation’s first seismic safety grading system for buildings during his State of the City address Thursday, when he also for the first time said he supports some type of mandatory retrofitting of older buildings that have a risk of collapse in a major earthquake.
Informing the public about the quake safety risks of buildings has been discussed for years but until now has gained little political traction. New Zealand is now developing its own building rating system after a devastating 2011 earthquake killed 185 people.
The details of L.A.'s rating system are still being worked out but it would involve some type of scientific assessment that would rank the safety of various buildings, said Lucy Jones, a U.S. Geological Survey seismologist whom Garcetti recently appointed as the city’s earthquake advisor.
Grading the quake risk would be a huge undertaking. The city would first have to agree on a standard for evaluating buildings. Then it would have to come up with a process for inspecting each building, a task that could be long and complicated. Finally, officials would need to decide how to publicize the grades, either using placards on buildings like the restaurant health grading system or on a website.
“How do you get a million evaluations done?” Jones said. “You realize that’s not something that’s going to happen in the next year.”
Still, Jones called Garcetti’s proposal “unprecedented” and said it was a significant move in improving seismic safety in Los Angeles.
Jones said a rating system developed by the U.S. Resiliency Council, a volunteer group of structural engineers, could serve as a model. That system uses ratings of 1 to 5 stars.
A 1-star building would signify multiple, widespread deaths, while 2 stars would warn of deaths in isolated areas. Three stars would mean no deaths; four stars, no injuries; and five stars would mean no one would be expected to be trapped. The stars could be posted in the lobby.
“We need to have very clear descriptions of what the ratings mean,” Jones said. “Something like, ‘This building can kill you’ or ‘This building you can probably use the next day.’ And some things in between. But I want the descriptions to be that clear because I think that this is only going to work if people understand it.”
The rating system is likely to face opposition from building owners, who in the past have feared that their properties would lose value if rated as being at risk in the event of a huge temblor. Jones said she has already been talking to owner and tenant groups about what the system could look like.
Ron Mayes, a Bay Area structural engineer and acting president of the U.S. Resiliency Council, said that right now, most tenants have no way of knowing whether their buildings pose a seismic risk.
“They have no clue what is the earthquake status of the building,” he said.
The San Francisco Planning and Urban Research Assn. in 2009 proposed a similar program using letter grades.
“A” grades would mean buildings would be operational after a quake, Bs would be usable while repairs were made and C buildings would have to be vacated during repair. D buildings wouldn’t cause fatalities but would be unrepairable, and E structures would be the most unsafe.
“For me, those are words that people understand,” said Chris Poland, a structural engineer and coauthor of the report. “The thing that bothers me is that there is no transparency, and people don’t understand, and they don’t even have a chance to make a decision.”
One class of buildings that poses particular risks in Los Angeles is older concrete buildings. A Times story in October reported that by the most conservative estimate, as many as 50 of the more than 1,000 older concrete buildings in the city — those built before 1976 — would collapse in a major earthquake, exposing thousands to injury or death.
The costs for an engineering assessment of a single building could be tens of thousands of dollars or more. The fixes could cost $1 million or more.
Wooden apartment buildings with weak ground floors have also generated concern. Known as “soft-story” structures, they often are built over carports and held up with slender columns. The 1994 Northridge earthquake damaged or destroyed about 200 of these structures, and 16 people died in the Northridge Meadows apartment complex when the upper floors collapsed onto the first floor.
Political opposition and a lack of interest on the City Council in the 1990s thwarted efforts to require older buildings to be strengthened against earthquakes.
Garcetti alluded to this past opposition during his speech Thursday, saying that should not prevent the city from taking action now, both on grading and on some type of mandatory retrofitting.
“Some critics say the cost of those upgrades may be high. But as we saw with hurricanes Sandy and Katrina, the cost of being unprepared is much higher,” he said.
The mayor also said that two recent moderate quakes in the area were “literal wake-up calls to remind us that the Big One is indeed coming.”
Jones said the city is still working on a specific retrofitting plan. Since the Times’ report, the City Council also has started studying various plans to strengthen both concrete and wood apartments.
“Nobody should die in a building in an earthquake. That’s our goal,” Jones said. “And we want to find a way to encourage doing more than that. Perhaps requiring the minimal retrofit and an incentive for going beyond the minimum. We’re still trying to figure out what’s going to work.”