Los Angeles city building officials have concluded that it would take inspectors more than a year to identify all the apartment buildings in the city that have a certain type of wood frame vulnerable to collapse in a major earthquake.
City staffers developed a plan to winnow out these so-called "soft" story wood-frame buildings among the 29,000 apartment buildings across the city that were built before 1978, Ifa Kashefi, chief of the engineering bureau at the building and safety department, wrote in a report submitted to a City Council planning committee.
Officials have long known about the risk of soft-story buildings, particularly after the Northridge earthquake in 1994, when about 200 of these structures were seriously damaged or destroyed, and 16 people died in the Northridge Meadows apartment complex.
Soft-story structures often are built over carports and held up with slender columns, leaving the upper floors to crash into ground-floor apartments during shaking. No city data exist to easily identify which structures are wood-framed and soft-story, Kashefi said.
The city's housing department provided addresses to 29,226 apartment buildings in the city built before 1978, according to Kashefi's report. Staffers would then use mapping programs to narrow down which apartment buildings need further field inspection.
The report estimates that 20% of the 29,226, or about 5,800 buildings, will be soft-story buildings, and an additional 11,690 buildings will need to be inspected on site to determine whether they are soft-story buildings or not.
Each inspector would be able to inspect about 30 buildings each day, according to the report, and the overall inventory effort would take about one year and a couple months, a department spokesman said.
A motion, introduced in July by City Councilman Tom LaBonge, asks building officials to present a proposal for how the city would be able to identify wood-frame soft-story residential buildings with at least two stories and at least five units and built before 1978.
LaBonge's motion came after San Francisco passed a landmark earthquake safety ordinance this year that requires about 3,000 wooden apartment buildings to be strengthened there.
L.A. Building and Safety officials are scheduled to present the report to a City Council committee Tuesday.