Corrosion Problems on New Bridge Date Back 9 Years

The old and new eastern spans of the Bay Bridge
The old and new eastern spans of the Bay Bridge. (Deborah Svoboda/KQED)

Update at 1:10 p.m: Caltrans has responded to the Sacramento Bee report: “All the Skyway tendons are stressed, properly grouted, and performing as designed and will do so for the next 150 years.”

Update at 10:15 a.m: Governor Jerry Brown said that he takes safety concerns about the Bay Bridge “very seriously, and that thing’s not going to open unless it’s ready.”

Corrosion problems have plagued the construction of the new eastern span of the Bay Bridge for years before anchor bolts snapped in March, the Sacramento Bee’s Charles Pillar reported this weekend:

• Beginning in 2004, inspectors frequently warned Caltrans about water leaks and corrosion.

• Experts blamed water problems on design or construction errors. Leaks of grout—a cement-based filler that normally prevents or halts corrosion—between hundreds of ducts forced long construction delays that left steel tendons exposed, making further corrosion likely.

• Caltrans used the wrong tests for corrosion, resulting in “essentially useless” findings, said UC Berkeley engineering professor Thomas Devine, an authority on corrosion-caused cracking in metals. He called the agency’s research “woefully inadequate” for detecting “environmentally assisted cracking,” which can worsen as tendons fatigue under stress, and can ultimately cause breaks.

This Caltrans video discusses the role of the various components, including the steel tendons meant to give the bridge ”extra strength and lift.”

A related video, dramatically called “The War on Corrosion” is also available on YouTube.

In a written statement in response to the Bee’s report, Bay Bridge project spokesman Andrew Gordon stated: “Corrosion has been an issue since the first steel bridge was built, and what we learned from this particular challenge six years ago is that we’re never going to be done fighting the battle against corrosion in the San Francisco Bay.”

 

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