It’s a disaster

Salty water swamping some Bay Bridge rods

By Jaxon Van Derbeken

The steel rod that is now the focus of a $4 million investigation into potential saltwater infiltration and corrosion on the new Bay Bridge eastern span is among a cluster of rods that were swamped by as much as 5 feet of water over a recent two-week period, The Chronicle has learned.

The prospective threat from salty San Francisco Bay is perhaps the most serious to the troubled $6.4 billion project, which has been dogged by failed rods, flawed welds, hundreds of deck leaks and misaligned deck sections. The 25-foot-long, high-strength steel rods provide an extra measure of protection for the bridge’s tower in a mega-earthquake — the kind the span is intended to survive.

The rod at the center of the investigation is at least 6 inches shorter than it is supposed to be, ultrasonic tests show, and it shifted upward two weeks ago when it was subjected to a machine pull test. Both are strong indications that the rod is corroded and broken, possibly because it sat in rainwater for several years thanks to a botched grouting and sealing job on its sleeve.

Caltrans says it won’t know for sure what is wrong with the rod until it is removed from its sleeve, which could happen as early as Monday. But in the meantime, new documents point to another possible source of infiltrating water — the bay, seeping in through the concrete-and-steel foundation — and suggest it is flooding other rods.

The risk to the tower is real, experts outside Caltrans say.

“You have all the ingredients for material failure here,” said Lisa Fulton, a corrosion expert in Berkeley who has tested samples of apparent corrosion residue found on the span.

“The fact that it’s flooded with saltwater basically guarantees corrosion,” Fulton said. “You can’t go back and fix it, because the damage is already done.”
Until recently, Caltrans officials downplayed the possibility that hydrogen-induced corrosion was attacking the towers’ 400-plus rods.

Caltrans district official Dan McElhinney suggested that the shortened rod had not been in place long enough or under sufficient stress to fracture. The chief engineer for the bridge project, Brian Maroney, theorized that the rod had been made shorter than the others or that its threads had been stripped when workers tensioned it — a less serious problem than if it corroded and snapped.

On Friday, Bill Casey, Caltrans’ chief resident engineer for the span, was reluctant to speculate. “We can’t say anything until we pull the rod out,” he said.

The latest bad news for Caltrans started in March, according to documents reviewed by The Chronicle. Crews had started to drain the hundreds of rod sleeves in which freshwater had accumulated because of an incomplete grouting and sealing job done by the project’s main contractor, the joint venture American Bridge/Fluor Enterprises. But soon, many of the sleeves began filling up again.

This new water had chloride levels that average more than 50 times what freshwater contains, suggesting that the source was saltwater coming in from the bay.

Saltwater is even more corrosive than freshwater, and Caltrans officials acknowledged that crews had previously attempted to fill cracks in the tower foundation that could now be a potential source of that saltwater.

One of the sleeves that was refilling with water was the one containing the unusually short rod, in the westernmost leg of the four-legged tower. A Caltrans accounting of tests shows that after they were drained last month, five other nearby rod sleeves also began refilling with water.

Over two weeks, the amount of water that collected in the sleeves ranged from 13 inches to 5 feet. The water from at least three of the sleeves tested showed elevated levels of chloride, Caltrans said.

Overall, of all the 421 remaining rod sleeves in the tower, about 100 gained some water over that two-week stretch, Caltrans found. The heaviest sleeve flooding was found on the western side of the tower.

Steve Heminger, executive director of the Metropolitan Transportation Commission, said the fact that the shortened rod is in an area where many rod sleeves are flooding does not prove it failed from water-borne corrosion.

“You ought to be careful about guilt by association,” he said. “We need to look all around where the problem is. Rather than speculate, I’m going to wait to get that rod out of there and we know what we have here.”

Still, Heminger said, if bay water is proved to be seeping into the foundation, it would pose a major issue for a project already dogged by what he called a “maddening” string of problems.

“We are going to get to the bottom of what is going on in there,” Heminger said. “If it is an ongoing intrusion, that is a much more serious development, a much bigger problem.”

He said the Federal Highway Administration has agreed to assist in the probe of the rod and water issues. The effort will be paid for out of $4 million in tollpayer money that the bridge oversight panel, chaired by Heminger, approved last week.

“We are going to have a whole mess of outside advice, and that’s what we need with a tough problem like this,” Heminger said.

One expert outside Caltrans said an influx of bay water would be an ominous development for the steel rods.

“They are almost guaranteed to have hydrogen-induced cracking,” said Charles McMahon, an emeritus materials science and engineering professor at the University of Pennsylvania who specializes in the study of fracturing of metals.

“With this material in a marine environment, failure is to be expected,” McMahon said. “It’s a disaster, a real disaster.”