Bay Bridge shut down due to broken cable | ABC30 Fresno

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By ABC30

Thursday, October 29, 2009

SAN FRANCISCO Crews worked against time and high winds to make the repairs. Caltrans says vibration from traffic and wind gusts of up to 55 mph contributed to the failure. But, it could be a couple weeks before the cause is fully understood.

Metal rods were used to secure a section of eyebeams where a crack was discovered during the Labor Day weekend closure. Contractor MCM is doing this repair. MCM Executive Ed Puchi says metal-on-metal vibration caused one rod to break off, which then caused a second one and a metal plate, to come crashing down on the upper deck.

Given that vibration on a bridge is not a surprise, ABC30 asked Puchi how this could have happened. "Well, I think what was unforeseen was the metal-to-metal rubbing at that location," he said Wednesday. When asked why it was unforeseen he said only, "I couldn't tell you."

MCM says the repair design includes enhanced anchor bolts that should prevent the metal-on-metal rubbing.

ABC30 asked Puchi if he was suggesting that that part of the mechanism was mis-designed. "I don't imagine exactly their contemplation was or what they planned with the original fix," he said.

Bay Bridge spokesman Bart Ney says Caltrans engineers signed off on the first repair. This time, Caltrans has asked the Federal Highway Administration and an independent panel of seismic safety experts to take a look.

"We're not doing this alone. We have the engineering community with us, looking at what the issues are, and basically vetting what some of our design changes are going to be with the enhancements that we will add to the system," Ney said.

The repairs to the bridge are actually happening in two phases, actually applying the new fix to the eyebeam, then testing that work. MCM, the contractor making the current repairs, is not the same contractor who made the repairs over Labor Day weekend. That was contractor CC Meyers.

During a Wednesday evening press conference Ney told reporters that Caltrans did not yet have an official time when the bridge would reopen.

Bay Bridge Closed Indefinitely