Caltrans has a $10 million plan to keep corrosive Bay water away from high strength rods designed to secure the tower of the new eastern span of the Bay Bridge in a quake.
Brian Maroney, the chief engineer on the $6.5 billion project for Caltrans, said dealing with the various water issues on the span has been grueling, but the end of its troubles with water and corrosion may be in sight.
“There’s been a lot of work and it’s been a long hard road,” he told NBC Bay Area News. “But everyone has had a sense that this is important to do.”
Water first became an issue on the span when high strength steel rods that hold down vital seismic stabilizers failed in March 2013. It turned out they were stewing in water for some five years and were attacked by hydrogen from the rainwater. Hydrogen makes high strength steel brittle over time.
Caltrans spent nearly $50 million on a retrofit for the broken rods and research on whether the more than 2,000 remaining similar rods were at risk of failing when exposed to water.
Then, in 2014, water became an issue again.
Caltrans discovered that the contractor bungled the grouting of many of the 400 rods that hold the tower down to the foundation in a quake. Some rods were unprotected and others only partly sealed – and more than one quarter were now stewing in water.
Local
The source turned out to be water both from rain and from the Bay, compounding the problems. Caltrans blamed the contractor, American Bridge/Fluor, a joint venture firm, for not properly grouting the rods to keep rainwater from getting into the sleeves.
But after the rods were drained, however, Caltrans discovered that water getting in from cracks in the foundation. Those cracks were supposed to be repaired when they were spotted during construction in 2007. But the high strength glue used to seal them apparently failed, allowing saltwater to get in.
On Thursday afternoon, a three member panel -- composed of the heads of Caltrans and the state and regional transportation agencies -- is expected to vote on Maroney’s plan to seal the rods for good.
Under the proposal, it could take crews two years to systematically remove all the problem grout that currently surrounds the more than 400 rods at the foundation base, then replace it with new material.
The $10 million proposed fix comes as the $6.5 billion project is now running $90 million in the red.
Maroney said the investigation was complex.
“We started pulling back layers of the onion, and we found a few more problems, a few more problems, until we diagnosed the whole thing,” he said.
The new grout the plan calls for will bolster the strength of the rods to resist the forces of a massive quake, Maroney says.
But Maroney acknowledges the proposal will be another hit to the cash strapped project, which is nearly complete.
“I’m asking for $10 million in construction funds,” he says. “That hurts, there’s no doubt about it.”
Another $10 million may be needed to protect the flooded steel foundation itself against corrosion. But on Thursday, Maroney will ask for $1 million to assess the corrosion risk to the now flooded foundation and come up with a plan to deal it. Just dealing with the grout, he says, will be major progress in dealing with the span’s water problems.
“I think we’re there – I’m really excited about it. That kind of wraps up the construction of the self-anchored suspension bridge,” Maroney said.
The oversight panel is expected to consider the measures at its meeting Thursday afternoon in Sacramento.
