Seismic Expert: Bay Bridge Could Open by Labor Day - NBC Bay Area

Seismic Expert: Bay Bridge Could Open by Labor Day

San Francisco-Oakland Bay Bridge officials are looking at a temporary fix for cracked seismic safety bolts that may allow the new eastern span to open as scheduled on Labor Day



    Seismic Expert: Bay Bridge Could Open by Labor Day

    A Toll Bridge Oversight Committee hearing was held Wednesday on the status of the Bay Bridge's eastern span. Jodi Hernandez reports. (Published Wednesday, July 10, 2013)

    Seismic safety experts said Wednesday an alternate fix for the new eastern span of the Bay Bridge could be done in a month, which would allow the bridge to open by Labor Day.

    The oversight committee said it would consider the plan, but said it still needs to be vetted. The temporary fix would include using wedges or shims to turn the bearings into sheer keys that would prevent movement during an earthquake. The idea would be to have the temporary fix in place to get the bridge open, while long-term repairs continue.

    Moving back the opening date was just one of the headlines from a Toll Bridge Oversight Committee hearing that was held on Wednesday.

    Caltrans officials gave more details Wednesday on its plans to repair cracked seismic safety bolts that have delayed the opening of the new span.

    The bridge was scheduled to open on Labor Day, but that has been delayed.

    A report released this week estimated the retrofit of the failed bolts will take months.

    The current problems started in March, when 32 of the 17-foot-long bolts that secure earthquake shock absorbers to the deck of the bridge were tightened.
    Tests found that hydrogen had infected the bolts, which were also made of poor quality steel, making them brittle. When tightened to high tension, the brittleness gave way, causing the cracks.

    The chairman of the Metropolitan Transportation Commission admitted mistakes were made.

    Steve Heminger said it is important to explain to the public what happened and why, adding that is the first step in restoring public trust.

    Heminger said the 2008 rods that broke were low quality. "The steel was not up to snuff," Heminger said, adding they will all be replaced.

    He said designers used the Richmond San Rafael Bridge as a model, and did not consider different uses and tension levels for the Bay Bridge in its embedded rod design.

    "This was a major part of the problem," Heminger said. 

    Caltrans director Malcolm Dougherty says going forward they will modify industry standards and make changes. He said crews will begin more tests of the bolts beginning th week of July 22.

    Steve Heminger said the bottom line is that it will be safe to open new Eastern span after replacing the capacity loss by failed 2008 rods.

    Engineers' review of other bolts throughout the structure has not found further problems, officials have said.

    Engineers will need to shut down the existing bridge for four days as they make final adjustments to divert traffic onto the new span.

    No official opening date has been set yet, officials said Wednesday.

    Heminger said all parties should help pay for the repairs.
    "If there's shared responsibility, we think there ought to be shared financial responsibility,'' Heminger said.
    Investigators said a faulty design also complicated repairs. The failed bolts were installed in an area of the bridge beneath a concrete cap that made removal impossible.
    The permanent repair is a steel saddle that would replace the clinching function of the failed bolts. It has been estimated to cost about $20 million.
    Officials said a review of other bolts throughout the structure have found no further problems, easing concerns that they could also have become brittle from exposure to hydrogen.