Bay Bridge rods, bolts are safe and can stay, draft report says

A puddle of water sits next to bolts on top of the Eastern span of the Bay Bridge in Oakland, CA Monday, February 10, 2014. A puddle of water sits next to bolts on top of the Eastern span of the Bay Bridge in Oakland, CA Monday, February 10, 2014. Photo: Michael Short / Special To The Chronicle Photo: Michael Short / Special To The Chronicle Image 1 of / 1 Caption Close Bay Bridge rods, bolts are safe and can stay, draft report says 1 / 1 Back to Gallery

More than 2,000 rods and bolts on the new Bay Bridge eastern span whose safety was questioned last year when 32 of them cracked are not in danger of failing and should remain in place, according to a report that an oversight panel will consider Friday.

The Toll Bridge Program Oversight Committee’s decision could lay to rest one of the biggest uncertainties hanging over the $6.4 billion project — whether hundreds of the steel fasteners will have to be replaced at toll payers’ expense.

The oversight panel — consisting of Caltrans’ director and the heads of the state and local transportation commissions — voted in a closed meeting Tuesday to release the draft report. The staff-prepared document outlines extra steps that should be taken to protect the galvanized steel fasteners while concluding that they can “safely remain in service with continued inspection and maintenance.”

The rods and bolts are in place throughout the span. They anchor its main cable to the road deck, secure it to the top of the tower and hold down structures designed to keep the bridge from swaying excessively in an earthquake.

Caltrans began a $20 million testing program for the rods and bolts after 32 of the high-strength fasteners snapped last year when they were tightened in their positions on two of the bridge’s eight seismic stabilizers. The agency also spent $25 million engineering a work-around for the stabilizers because of questions about the safety of another 64 rods and bolts that were made in the same batch as the ones that failed.

Those rods and bolts, delivered to the bridge construction site in 2008, sat in pools of rainwater for as much as five years before they were tightened, investigators found. The draft report to be considered Friday concluded that the remaining 2,210 fasteners were safe both because they had not been submerged in water — which can allow embrittling hydrogen into the metal — and because they were “fabricated differently and installed differently.”

The report’s findings were based on tests in which rods and bolts were submerged in saltwater and stressed over time. Some failed at below their rated strength, but the report found that they were failing while holding greater loads than they would have to hold on the span.

The rods that failed last year, unlike the balance of the steel fasteners on the span, lacked a basic property of steel known as toughness, which resists cracking, the report found. It said the remaining rods and bolts are safe at current tension levels because they are tougher.

Caltrans has already started adding protection for the remaining rods and bolts, covering many of them with water-repelling grease or painting them with a protective layer to keep embrittling hydrogen out.

Caltrans’ testing program has come under fire from a retired Bechtel engineer, Yun Chung, who told the bridge panel in an unsolicited report this month that the effort was “unscientific” and its findings “erroneous.”

Chung said the testing was too limited to prove that the rods and bolts won’t crack, even at their current level of tension. In some cases, the rods’ tension levels are too close to the safety threshold, he said, accusing testers of not taking into account the possibility that stress levels can be elevated where the rods and bolts are secured by nuts.

He said Caltrans should replace hundreds of the rods. The oversight committee’s draft report said staffers had considered the possibility but rejected it in favor of adding protective measures, “since it is safer for workers, more timely, more cost effective and ... is consistent with industry experience.”

Jaxon Van Derbeken is a San Francisco Chronicle staff writer. E-mail: jvanderbeken@sfchronicle.com