OAKLAND, Calif. – The planned repair for broken seismic safety rods on the new span of the San Francisco-Oakland Bay Bridge could cost between $5 million and $10 million, a state transportation official said Wednesday.
Officials still don’t know whether the repair will be done in time for the span’s scheduled Labor Day opening, but say it’s still possible. A decision is expected May 29.
California Transportation Commission Executive Director Andre Boutros told a meeting of the Bay Area Toll Authority that the repair for the 32 snapped rods involves installing steel saddles.
The saddles would be placed over the base of the seismic shock absorber that was initially intended to attach to the bridge by the rods. About 430 steel cables covered in concrete will tie down the saddles. Another repair option would have been more expensive.
Officials said they aren’t taking short cuts in an attempt to get the bridge opened on schedule.
“We’re dealing here with not only engineering concerns but public confidence, and public confidence has taken a beating over the last few weeks, and we are mindful of that,” said Steve Heminger, executive director of the Metropolitan Transportation Commission.
Bridge officials Wednesday also sent a letter to the Federal Highway Administration requesting an independent review of the California Department of Transportation’s investigation into the broken rods, and the chosen fix.
The rods connect earthquake safety devices called shear keys to the deck of the bridge and a large concrete cap. Shear keys are like big, steel shock absorbers that help control swaying during an earthquake.
The new bridge, which is replacing a span damaged during the 1989 Loma Prieta earthquake, is already years late in opening and billions of dollars over budget.
Documents released last month by the California Department of Transportation show its inspectors found structural integrity issues with some of the rods several years ago, before they were installed.
The documents were unclear about whether the problems were remedied before the rods were delivered and installed, but official later said they were. The inspectors noted that they failed elongation tests for structural integrity and said they were concerned about the quality of work by the company that galvanized them to prevent corrosion.
According to a metallurgists’ investigative report released Wednesday, the steel in the broken rods was “found to be less than ideal.”
The report said the hydrogen corrosion in the rods could have been discovered earlier if Caltrans had required tougher tests. The agency is developing new requirements that would require more testing in the future.
Crews also are testing bolts installed in shear keys on other parts of the bridge. So far there have been no signs of weakness, Heminger said.
Also, bridge crews are developing further “wet tests” to address concerns that bolts might corrode in the future.
“After the wet tests we’ll know whether these bolts are OK or not, and those that are not we’re going to rip them out and replace them,” Marwan Nader, a bridge structural engineer working on the repairs, said.
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