Can a temporary patch done on the fly hold the aging and increasingly fragile Bay Bridge together? Should we even be trying? Those are questions state highway officials face this week as they struggle for the second time since September to concoct a quick fix for a crack on the eastern span of the bridge.
Apologetic Caltrans officials said Wednesday evening they likely will extend this week's bridge closure a third day today. They adamantly declined to offer any estimate of when the bridge might reopen.
Motorists unable to use the Bay Bridge jammed alternate routes and Bay Area Rapid Transit on Wednesday. Others flocked to the ferries that cross the bay.
Alarmed California Department of Transportation officials closed the bridge Tuesday when a newly installed 100-foot-long steel rod snapped, pulling another rod and part of a 6,000-pound steel clamp onto the road during the evening commute, damaging three vehicles, but causing only minor injuries.
The incident has put Caltrans on the defensive and launched concerns about the agency's ability to assure a safe bridge.
Inspectors found the 2-inch crack in a beam on the east span's cantilever section two months ago while the bridge was shut for work as part of a multiyear construction of a seismically safe replacement span.
Caltrans engineers quickly designed a "unique" repair, essentially a steel splint to take weight off the cracked beam, and reopened the bridge three days later, assuring drivers the bridge was safe.
Wednesday night, Caltrans officials acknowledged the design did not work. They said they believe high wind caused the patch's metal rods to vibrate and rub against other metal, causing one to break.
"In retrospect, we should have done more isolation on those tie rods, so they wouldn't have vibration issues that they had," said Caltrans spokesman Bart Ney.
Ney said officials are redoing the fix, but bolstering it with new crossbars, stronger welds and wider clearances where the rods rubbed against brackets.
Caltrans officials said inspectors had been up looking at the repair patch most weekends since it was installed, and recently saw where rods were rubbing. Before they could decide on new work, a rod snapped Tuesday.
Ney said engineers are working out final design details for the repair, but he and other officials said they are confident the fix will stick.
Caltrans toll bridge program manager Tony Anziano responded sharply when asked if Caltrans believes it erred by reopening the bridge hastily after the initial fix, and whether the agency would back off its policy of quick fixes.
"The short answer is no," Anziano said. "That assumes we went too fast in the initial repair work. That was not the case."
He said Caltrans tries to work fast when it has to close major roads, but "we do not open facilities if we do not fundamentally believe it is safe."
Engineering experts weighed in Wednesday, some offering cautions, but also saying the failure of the Labor Day solution doesn't mean bridges can't be fixed quickly.
Dawn Cheng, assistant professor of civil engineering at the University of California at Davis, said she was "shocked" by the failure.
"Those emergency patching techniques should work," she said. She called Tuesday night's problem "one of the very rare ones."
But experts also said a temporary remedy is no match for replacing aging structures.
"There is such a thing as a safe, temporary fix, (but) our nation is faced with thousands of bridges that are structurally deficient," said Thomas Young, a former Caltrans bridge engineer and head of Civ-Tek engineering in Rocklin. "In the broader issue, the Band-Aids don't work."
Noting that commuters could have been killed, Young said Caltrans should submit its solution to an outside expert to verify its safety.
Caltrans officials said they are submitting their designs to an agency peer review group.
Federal Highway Administration officials were on the scene to review Caltrans' plans Wednesday, a representative said, but the agency is not independently investigating the failure.
This week's failure comes 20 years to the month after the Loma Prieta earthquake damaged the bridge, forcing a monthlong closure and prompting the state to launch a multibillion dollar effort to solidify major bridges.
The Bay Bridge west span, connecting with San Francisco, has been upgraded, as have other Bay Area bridges. But the east span was determined unsuitable for repair.
Rancho Cordova contractor C.C. Myers did the original repair. Caltrans officials said they have found no problems with the company's work.
MCM Construction of North Highlands is doing the fix instead of Myers. Both had crews working on the new bridge when the rod failed. MCM crews got to the scene first, officials said.