Early last year, the City of Santa Monica announced plans to inventory all of the commercial and residential buildings that could collapse during a major quake.
That project is taking longer than expected, in part because more potentially vulnerable structures are turning up.
Ron Takiguchi, with Santa Monica’s Department of Building and Safety, said his team is in the process of identifying certain concrete, steel frame and wood frame buildings that are known to be vulnerable to collapse during large earthquakes.
Of particular concern are wood frame buildings called “soft story.” These are multi-level structures usually with an open garage on the ground floor and apartments on top, supported by weak pillars.
One such structure, the Northridge Meadows apartment complex, collapsed during the 1994 Northridge quake, killing 16 people.
The city had hoped to have a list of such buildings compiled by summer 2014.
Takiguchi says his team initially identified more than 2,000 potential soft story buildings last year using zoning maps and visual inspections from streets and alleyways.
However, as they examined city records, it became clear that they may have missed some soft story structures.
"Some buildings were behind others," he said. "They couldn’t be identified from the street or the alley."
Other buildings, he said, had garage doors closed making it tough to determine the design of the ground floor by simply looking at the structure.
Takiguchi said his team is finishing up a second round of visual surveys to locate any soft story buildings missed during the first one.
He expects to have that work done sometime in January or February. After potential soft story designs have been identified, the building and safety department will examine records on each address and see if previous retrofits have been completed.
Those properties that are either not soft story design or show adequate upgrades will be taken off the list.
In addition to soft story buildings, Santa Monica hired a contractor to help identify seismically vulnerable concrete and steel buildings. So far less than 300 have been found.
"We're looking at all types of potentially hazardous buildings," Takiguchi said.
Once the lists are complete, Santa Monica will work with the Structural Engineers Association of Southern California to come up with guidelines for retrofitting various building types.
Takiguchi says the long term goal is to require owners to upgrade up their vulnerable structures to the standards outlined in the guidelines.
In the meantime, officials from Santa Monica have been in communication with the Los Angeles Department of Building and Safety, since L.A. is working on a similar inventory of vulnerable buildings.
Takiguchi says he is also speaking with officials from San Francisco. That city called for mandatory retrofits of soft story buildings in 2013.