Construction crews working on the Bay Bridge retrofitting project discovered a crack Saturday night that could keep the heavily traveled bridge closed beyond its scheduled reopening at 5 a.m. Tuesday.
The bridge has been closed since Thursday night.
On average, 280,000 vehicles cross the bridge every day, according to Caltrans. It was closed Thursday night as part of a planned seismic retrofitting project that requires cutting out and replacing a double-deck section of the east span.
A 50-foot section of the bridge collapsed in 1989 during the Loma Prieta earthquake, prompting efforts to make it more quake tolerant.
After a snag on Friday afternoon, construction crews for the Bay Bridge were able to successfully remove the 300-foot, 3200-ton section of double-decker freeway from the existing bridge, easing it out of place at a rate of about 20 feet per hour.
As they were prepping to insert the new section of roadway, an inspection of the east span of the bridge showed a crack in one of the eyebars on the side of the structure, said Bart Ney, spokesman for the California Department of Transportation.
Caltrans determined that the two-inch beam was cracked through about halfway, and declared the problem to be "significant enough to have closed the bridge on its own." Crews are now undergoing emergency repair of the crack, and the bridge will not be reopen until both the repairs and the planned detour construction are complete.
While the planned work at Yerba Buena Island is on schedule to be completed by the planned reopening of 5 a.m. Tuesday, also finishing the emergency repairs on the crack by Tuesday would be a "monumental effort," and thus may require postponing the reopening beyond Tuesday, Ney said.
"It's a significant crack, significant enough to have closed the bridge on its own," he said in a news conference aired on the agency's Web site Saturday night.
Ney said the crack has to be repaired immediately and acknowledged that the work may stretch past Tuesday when the bridge was scheduled to reopen.
"I want to assure everyone that this repair will be made and we will return the Bay Bridge safer than when we took it out," he said.
It's not yet clear when the bridge will be reopened. In the meantime, ongoing updates are being posted on BayBridgeInfo.org.
This is the third time in four years that Caltrans has closed the bridge over Labor Day weekend to do important work so that a new, more seismically safe eastern span can open on schedule in 2013. The cost of the entire project is estimated to be $5.7 billion.
Caltrans has been building a new eastern span and upgrading the western side of the bridge in the wake of the 1989 Loma Prieta earthquake, which damaged the bridge and forced it to be closed for a month.
But the closure of the bridge Friday was the first time it was be closed on a regular commute day for seismic work.
The work to replace a section of the Bay Bridge east of the Yerba Buena Island Tunnel to connect the bridge to a temporary detour is one of the biggest and most important parts of the project to build the new eastern span, Ney said.
Ney said when the work is completed, traffic will flow on a half-mile long replica of the bridge connecting the new eastern span to the Yerba Buena Island Tunnel.
The replacement will allow crews to demolish a portion of the original bridge and build a new, permanent connector from the tunnel to the new eastern span, he said.
Ney said motorists will have to use the half-mile-long detour for three or four years while the old approach to the Yerba Buena Island Tunnel is demolished.
There are "safety concerns" about the detour because it has sharp, S-shaped curves, Ney said. As a result, the speed limit on that section will be reduced from 50 miles per hour to 40 mph and it will be strictly enforced.
Ney said Caltrans was able to reopen the bridge 11 hours ahead of schedule on Labor Day weekend in 2007 but he said the construction work this year will be more challenging than last time.
The cost of putting in the new section has increased dramatically in the last several years, from $34 million to $140 million.
Ney said one reason the cost increased so much is that design changes were made after engineers determined that more should be done to prevent the bridge from collapsing in a major earthquake.
Another reason is that it was decided that more steel should be used for the project and the cost of steel escalated, he said.