City Advised To Require Building Retrofits
Robert Selna, Chronicle Staff Writer
San Francisco should force owners of the city's weakest buildings to evaluate their properties' seismic safety and complete any necessary retrofit work, according to a new report.
At a minimum, such a mandate would cover about 2,800 large, wood-frame buildings that are liable to collapse or sustain serious damage in a major earthquake. Such a temblor is likely to hit the city before 2032, the report states.
The draft report was reviewed Wednesday by the city's Building Inspection Commission, and a final version is scheduled to be delivered to Mayor Gavin Newsom by Jan. 30.
The report estimates that mandatory retrofits would dramatically reduce damage and the need for emergency shelters and would preserve rental housing and neighborhood character. Retrofits could cost $9,000 t0 $28,000 per residential unit.
The city could help building owners pay for the retrofit work by offering low-interest loans backed by bonds, but the bonds would need voter approval.
The buildings that were analyzed house nearly 60,000 residents and 7,000 employees but represent just a fraction of the buildings that would be destroyed in the city if a big temblor hit today. The buildings studied make up only 10 percent of the city's residential units that are believed to be unsafe. Other building types will be studied later.
"This data is a confirmation that these buildings represent a significant hazard to the community and possibly all sorts of problems," said Laurence Kornfield, the city's chief building inspector.
In July, Newsom said he did not feel that it was necessary to require owners to shore up their buildings as other Bay Area cities have done. Last month, Newsom said he would be willing to reconsider after reviewing more data. On Wednesday, his spokesman reiterated that sentiment.
"There appears to be a growing consensus for a mandatory program. After the final recommendations are presented to him, Mayor Newsom will weigh the evidence and make a policy decision," spokesman Nathan Ballard wrote in an e-mail.
At issue are wood-frame, "soft-story" structures. They include the classic San Francisco apartment building with a store or restaurant on the first floor. They have a ground-floor space - for example, a large window or garage door - where a solid wall might otherwise be.
San Francisco has more of those buildings than any other Bay Area city, and they are made more precarious by neighborhoods perched on unstable soil. The open spaces in walls make the frames prone to twisting and buckling, and many of the buildings were damaged in the Marina district in the 1989 Loma Prieta earthquake.
The city-funded study focused on 2,800 buildings that have three stories or more, at least five residential units and proportionally large ground-level openings. The study notes that the city has thousands of other types of soft-story buildings, such as homes built over garages like those common in the Sunset District.
Many of the buildings under review were constructed before 1906, and 90 percent are rental apartments. Surveys indicate that the vulnerable soft-story buildings are most concentrated in six neighborhoods: the Mission, the Western Addition, the Richmond, North Beach, Pacific Heights and the Sunset.
The draft report is part of the city's first endeavor to fully understand the health, safety and economic risk posed by the city's buildings during a major earthquake. It considered the result of a 7.2 earthquake on the San Andreas Fault, which lies just off the city's western shore about 10 miles from downtown. The study also reviewed a span of quakes from magnitude 6.9 (Loma Prieta) to 7.9 (the 1906 quake).
A Chronicle report in June highlighted the fact that the city had no strategy for fixing the problem despite the fact that the danger of soft-story buildings had been known for decades.
As part of a study that had recently been restarted by the city's Department of Building Inspection, Newsom directed departments and earthquake consultants to analyze soft-story structures and to develop retrofit guidelines for them by the end of this month.
The study calls for mandatory retrofits within a 10-year period. The repairs would have to be sufficient to ensure that the buildings can be lived in after a large quake.
It also said the city should offer incentives to encourage property owners to retrofit. One option is to offer loans using several hundred million dollars in city bond funds that were previously set aside for fixing brick buildings.
Estimates put the total cost of retrofitting just the weakest soft-story buildings at $260 million. That could eliminate $1.5 billion in damage in the event of a big earthquake.
One member of the city's Building Inspection Commission who reviewed the report implied that property owners would need more than health and safety as incentive to retrofit.
"You've really got to make it attractive to individual homeowners to do this work ... it gets back to incentives," Commissioner Mel Murphy said.
Others were gung-ho about a city retrofit requirement.
"I think we need to mandate this," said Commissioner Debra Walker, who is planning a run for the Board of Supervisors. "It's scary for people financially, but it's much more scary to think about these things falling down and much more expensive if we don't do it."
A searchable database includes addresses of buildings that could be forced to undergo expensive retrofits under a new proposal. sfgate.com/webdb/softstory
This article appeared on page A - 1 of the San Francisco Chronicle