High winds hampered efforts Wednesday to make repairs and reopen the San Francisco-Oakland Bay Bridge after two rods and a 5,000-pound crossbeam fell into traffic lanes.
Three cars were damaged, and one person suffered minor injuries when the metal debris fell onto the heavily used span during rush hour Tuesday.
Construction crews working through the night fought winds that gusted to 35 mph as they brought in heavy machinery to try to move the metal and make the repairs.
"We have several thousand pounds of steel we have to place hundreds of feet off the deck, so worker safety is a concern," said Bart Ney, a spokesman for the state Transportation Department
There was a chance the bridge could reopen Thursday, he said, noting wind was a contributing factor in the failure of the rods.
Traffic was jammed early Wednesday on other San Francisco-area highways, as motorists looked for alternatives to the bridge, which carries about 280,000 cars each day.
The pieces that broke were part of major repairs done over Labor Day weekend after crews discovered a cracked link during an earthquake safety upgrade. The rods that broke were holding a saddle-like cap that had been installed over the cracked link.
Federal officials are sending engineers to find out what caused the repair to fail. Federal Highway Administration spokeswoman Nancy Singer said the agency did not inspect the original Labor Day weekend repair, relying only on state inspection reports.
Singer said the agency's bridge experts have been dispatched to assist the state Transportation Department in finding out why that fix failed.
When a rod snapped about 5:30 p.m. Tuesday, it brought down a steel patch roughly three feet long, authorities said.
"It's a very fortunate situation," said California Highway Patrol Sgt. Trent Cross. "It was in the heart of the evening commute and you had a 5,000 pound chunk of metal fall approximately 100 feet."
The Bay Area Rapid Transit Agency increased service to accommodate commuters.
Abolhassan Astaneh-Asl, a civil engineering professor at the University of California, Berkeley, who has spent 20 years studying the Bay Bridge, called the initial crack a "warning sign" of potentially bigger safety issues with the bridge.
"The repair they were doing was really a Band-Aid," said Astaneh-Asl, who criticized Caltrans at the time for rushing to reopen the bridge.
Astaneh-Asl said the failure of the repair job demonstrates the need for a longer-term solution. The age and design of the bridge make it susceptible to collapse, especially if commercial tractor-trailers are allowed to continue using it, he said.
"I think Caltrans is putting public relations ahead of public safety," he said.