Bay Bridge Leaks Prompt New Fastener Fears
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MEDIA SPOTLIGHT – “Several of the giant steel rods that anchor the tower of the new Bay Bridge eastern span to its base have been exposed to water — possibly for years — that could cause corrosion to attack them,” the San Francisco Chronicle reports.
The problem reportedly exists in nearly a dozen galvanized rods. While Caltrans has drained the water, it’s unclear whether the rods have been damaged, writes Chronicle reporter Jaxon Van Derbeken.
The news evokes memories of March 2013, when rainwater doused many of the 32 rods that snapped after being tensioned on the $6.4 billion bridge. Those rods were used to anchor seismic stabilizers, according to the Chronicle.
Caltrans spent $25 million on a replacement system for those rods, which failed due to hydrogen embrittlement. Testing on the 2,000 remaining bridge rods costs an additional $20 million. Final results of the study are due by early October.
The latest corrosion issue presents a different problem.
“The 525-foot tower is bolted to its base with 424 steel rods,” writes Van Derbeken. “The rods, each 25 feet long and about 3 inches thick, sit in steel sleeves that are filled to near their top by moisture-proof grout, covered by a ring of foam and then sealed by caulking.”
Somehow water was trapped between the grout and the caulking, most likely before the tower was lowered into position in 2010. And while the tower chamber housing the rods has a dehumidification system, the system couldn’t dry out the rod sleeves because the water was buried under the caulk, bridge officials told the Chronicle.
“Testing the water for zinc, which is left behind when hydrogen attacks galvanized steel, will help determine if the rods have been compromised.”
Editor’s Note: Articles in Media Spotlight are excerpts from publications or broadcasts, which show the industry what the public is reading or hearing about fasteners and fastener companies. ©2014 Fastener Industry News
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