Los Angeles approves sweeping earthquake safety rules covering thousands of buildings
Downtown Los Angeles is shown in front of snow-capped mountains on a rare smog-free day, on Dec. 18, 2006. Photo by Lucy Nicholson for Reuters.

Los Angeles on Friday approved safety standards that will require earthquake retrofits at thousands of apartment buildings and establish the nation's toughest rules for structurally weak concrete buildings.

The rules will apply to 13,500 wood-frame buildings with so-called soft first-stories, which often consist of thin pillars supporting upper floors in an area where tenants park, and 1,500 so-called brittle concrete buildings, which lack the ability to waver or bend in a temblor, the mayor's office said.

Many soft first-story buildings are rent-stabilized, which prompted concerns that any damage to the residences would wipe out Los Angeles' already limited affordable-housing stock.

San Francisco and a few other California cities have instituted rules for soft first-story buildings.

But the Los Angeles ordinance, which passed the City Council by a unanimous vote on Friday and was quickly signed by Mayor Eric Garcetti, marks the first time a U.S. city has mandated retrofits of brittle concrete buildings, said U.S. Geological Survey seismologist Lucy Jones, who last year was hired by Los Angeles as an adviser on earthquake safety.

"I applaud the mayor and City Council for their commitment to a safer Los Angeles that will be here for future generations," Jones said.

Owners of the brittle concrete properties, which also are called non-ductile concrete buildings, will have 25 years to complete strengthening upgrades while owners of soft first-story wood-frame properties will have seven years to finish the work, officials said.

The vulnerability of soft first-story buildings, many of which were built in the 1960s as apartments with tuck-under parking, became clear in the 1994 Northridge earthquake when one collapsed in Los Angeles and killed 16 people.

California cities are seen as facing a high risk of extensive damage from weak buildings in an earthquake, and officials have warned that based on historical patterns the state could be due for a major temblor.

"We’re leading the nation in requiring this level of building safety retrofit before, not after, the big quake we know is coming," Garcetti said in a statement.

Los Angeles officials have not made any firm commitment to help fund the sweeping retrofits at commercial and apartment buildings, and plans to pay for the work are still being formulated.

(Reporting by Daina Beth Solomon; Editing by Alex Dobuzinskis and Eric Beech)