Bay Bridge Bolts Get ‘Simple, Cut-Rate’ Fix

April 30

00:00 2014

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FEATURE

The state agency in charge of the $6.4 billion Oakland Bay Bridge “installed a relatively cheap and simple fix” for 192 galvanized high-strength rods susceptible to hydrogen embrittlement, the San Francisco Chronicle reports.

“Caltrans put the fix in place for 192 rods installed near where the cracking problem first became apparent last year, when 32 of the high-strength rods used to hold down one of the bridge’s seismic shock absorbers snapped,” writes Jaxon Van Derbeken of the Chronicle.

After years of marine exposure, the rods broke within days of tensioning. Testing revealed the giant fasteners were manufactured harder than allowed by Caltrans regulations, making them “unusually susceptible to hydrogen,” which can cause steel to crack.

The fix – a steel cap “placed over the nuts on the heads of the rods and filled with special grease” – cost $189,000 to install on the nearly two hundred rods, according to the Chronicle.

“The grease acts as a shield against the electrochemical reaction” that makes steel brittle, Van Derbeken writes.

After the rods broke in 2013, Caltrans initiated a study to test 2,200 bolts and rods for hydrogen embrittlement. Early results “confirmed that the remaining rods…could fail prematurely.”

But the study’s cost – $10 million – has been criticized, leading State Sen. Mark DeSaulnier (D-Concord) to call for its termination now that a remedy has been found.

“They should just do their job – focus on getting the work done, making sure the bolts are safe, in a cost-effective way,” DeSaulnier said.

Bridge officials defended the testing program.

“If we simply installed grease caps on all the rods and did not do the testing, then we would no doubt be criticized by the media for applying a one-size-fits-all solution that provides absolutely no data about the long-term prospects of the rods,” bridge spokesman Andrew Gordon told the Chronicle.

“We want as much information as possible before making any final decisions about those other rods.”

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