Los Angeles city officials and property owners are making progress retrofitting the types of apartment buildings that proved especially vulnerable in the 1994 Northridge earthquake. The devastating—and deadly—temblor struck 25 years ago this week, toppling and damaging tens of thousands of buildings.
As of this month, 1,500 “soft-story” buildings have been retrofitted, and roughly 6,400 are in-progress, according to figures from the city’s building and safety department.
Owners for about 5,000 buildings have yet to submit retrofitting plans, the first major benchmark in the process. But “orders to comply” have been issued for all of the 12,865 soft-story buildings that need seismic upgrades.
The orders are the first step in the city’s mandatory retrofit program, which requires owners, within two years, to either submit proof that their structures have already been retrofitted or file plans to do so.
The city’s chief resilience officer Marissa Aho called the progress “really exciting news.”
“We’re ahead in terms of the number of buildings” that have met their two-year compliance deadline so far, Aho says.
She said the city made an effort to send orders to comply to the owners of larger buildings first, so the retrofits would begin quickest for the bulk of the units that needed them.
Soft-story buildings are wood-frame structures where the first story is largely open— like LA’s famed dingbat-style apartment buildings, which contain open space for parking on their first floors.
The Northridge earthquake highlighted the vulnerabilities of these types of buildings and their proliferation throughout the city.
Approximately 49,000 apartment units in LA were destroyed or seriously damaged due to the Northridge earthquake; two-thirds of those were in soft-story buildings, according to a 2006 report from the Public Policy Institute of California.
Twenty one years after Northridge, in 2015, the city rolled out a program requiring property owners to strengthen these buildings to withstand earthquakes. It began sending notices to property owners in May 2016, according to the city’s department of building and safety.
Last year at this time, retrofits on 608 soft-story buildings were complete and another almost 4,000 retrofits were in progress, according to the mayor’s office. The new numbers show that those totals have at least doubled since then.
Retrofits are also required for nearly 1,500 non-ductile concrete buildings built before 1977, another type of structure prone to collapsing. They have been identified by seismologist Lucy Jones as “the deadliest buildings when they fall.”
By the end of 2018, the city had issued orders to comply to about 1,200 non-ductile concrete buildings. Owners for about 160 of those structures have begun the retrofitting process. They have 25 years to complete construction.
Mandatory building retrofits are part of a larger plan released in 2014 focused on preparing the city to weather and bounce back from a major earthquake.
The plan made a variety of recommendations aimed at better earthquake preparedness, including upgrades to water delivery systems and mandating cell phone towers that are less likely to topple in a quake.
With a 93 percent chance that an earthquake as big as the deadly Northridge quake (or bigger) will strike Los Angeles again in less than 30 years, the city’s upgrades can’t come soon enough.