Caltrans first announced they had a problem with the bolts several weeks ago, citing "hydrogen infiltration." But on Wednesday, they said they still hadn't determined the source of that hydrogen or come up with a solution. Metropolitan Transportation and Caltrans officials now acknowledge that the new Bay Bridge may not be ready to open as planned.
"I'm trying not to give you a sense either way today that we're definitely going to make it or we're definitely going to miss it. We don't know enough to say," said Steve Heminger with MTC.
The possible delay involves the 96 giant rods or bolts installed beneath the bridge, an important tool for reinforcing the span during a large earthquake. They were manufactured in 2008 by Ohio-based Dyson Corporation. Last month, Caltrans revealed that one-third of the 96 failed or cracked when tightened.
Caltrans engineers believe hydrogen somehow entered the steel when it was galvanized by the manufacturer or rainwater could have seeped in after they were installed. Asked wouldn't they protect against water getting in, Steve Maller with the California Transportation Commission replied, "It was protected to the extent that it was protected, but nobody thought, probably, about how these things would be reacting."
Thomas Devine is a steel expert, a professor in the Materials, Science and Engineering Department at UC Berkeley. He says, "It's not impossible to embrittle high-strength steel by exposure to water. However, should that happen, you would have to feel that the galvanized steel was either improperly fabricated or that the high-strength steel was improperly manufactured."
Last week, a new batch of 192 bolts made by Dyson in 2010 were tensioned. So far, they seem to be fine. "We're going to subject them to fairly lengthy testing and analysis but at this point in time, everything else looks good," said Tony Anziano with Caltrans.
Caltrans says that since the faulty bolts are strictly related to the bridge's function in an earthquake, they could open the bridge as scheduled on Labor Day even while the work to repair the bad bolts is under way. Of course they would first have to determine that the new bridge, with the bad bolts, would be safer for drivers than the old bridge.