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transportation
BRIDGES
Bay Bridge Rehab Gets a Lift With 6,500-Ton Deck Section
 
By Greg Aragon
Bay Bridge Rehab Gets a Lift With 6,500-Ton Deck Section
Bay Bridge Rehab Gets a Lift With 6,500-Ton Deck Section
Contractor had Labor Day weekend to replace a big piece of Bay Bridge, but finished 11 hours ahead of schedule.

Over the Labor Day weekend, a contractor lifted out a 6,500-ton, football-field-sized slab of roadway connecting the San Francisco-Oakland Bay Bridge to Yerba Buena Island, fitting it with a more suitable seismic replacement. It was the first time a fully constructed bridge deck had been lifted into position in the state.

Led by Rancho Cordova, Calif.-based C.C. Myers Inc., the $40-million west tie-in project began on Aug. 31 at 8:40 p.m. and ended on Sept. 3 at 6 p.m., 11 hours ahead of schedule. The contractor did not receive a bonus for finishing early but faced no penalties if the project was tardy.

After closing the bridge to traffic, work began with demolition of the existing five-lane-wide Interstate 80 viaduct section just east of the Yerba Buena Island Tunnel using 12 water-cooled saws to cut up the deck. Crews then used 600-ton cranes to lift out 63 reinforced concrete beams.

After the area was cleaned, crews laid eight tracks on the lower deck of the Bay Bridge. The new 6,500-ton section was lifted a few inches off its temporary supports and rolled into place on the bridge's upper deck using 16 computer-controlled hydraulic skid jacks. Since January, workers had been constructing the new 350-ft-long by 95-ft-wide section, about 100 ft south of the bridge portion it replaced.

“We had a total of 3 in. of tolerance on each side to move this big piece into place,” says Caltrans spokesman Bart Ney. He says one of the biggest challenges of the job was getting the word out to the 280,000 drivers who use the bridge daily that it would be closed.

Related Links:

Early Opening Earns Highway Contractor $5-Million Bonus,

“Managing the work straight for 81 hours without a break” was another challenge, says Linda J. Clifford, chief financial officer for C.C. Myers. “Obviously, keeping crews alert and safe [was] more difficult under these circumstances.” She says that moving a fully constructed bridge deck into place has never been done before in California.

The new bridge section was placed on 12 new 6-ft-diameter piles that were cast in drilled holes between 50 ft and 80 ft deep. “The support has piles that go much deeper than the existing structure, which uses a spread- pile foundation,” says Ney.

This project is part of a $5.3-billion, five-phase effort to reconstruct and retrofit the Bay Bridge’s east span, a job that will be completed in 2013 and include a self-anchored suspension main span. This is the first time the connection between the East Bay and San Francisco has been closed since the 1989 Loma Prieta earthquake.

“We were really happy that the equipment that transferred the new deck into position worked so well,” says Clinton C. Myers, the contractor’s chief operating officer. “The equipment worked exactly as promised, and the bridge deck was in place in much less time than originally anticipated. Considering we went through the entire weekend without issuing even a Band-Aid, it was great to be so safe and get the work done ahead of schedule too.”

 

 


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