3/16/2015 1:08:00 AM
NEWS BRIEFS
Cracking on Bay Bridge Rods ‘Widespread’
Courtesy the San Francisco Chronicle
Tests on one of the high-strength steel rods that secure the base of the tower of the new Bay Bridge eastern span show more widespread cracking than Caltrans officials had previously acknowledged, according to the San Francisco Chronicle.
“Rust and microscopic cracking were found after one of 424 fasteners intended to keep the tower from being damaged in an earthquake was removed for testing last year,” writes Jaxon Van Derbeken of the Chronicle.
“The problems were found on the lower part of the rod, which became flooded because of a botched grouting and caulking job during construction — a mistake that resulted in many of the 25-foot-long fasteners stewing in water for several years.”
Testing documents indicate that cracks were also found “at the top, where the rod had been under stress but had not been soaking in water.”
The Chronicle called the discovery “a troubling development for Caltrans because such cracks can get worse over time, leading to total failure, possibly during a quake.”
Caltrans has acknowledged the rods “were put at greater risk of cracking during processing, suffered damage in shipment, were left standing in corrosive water and then put under heightened stress when the tower was pulled back to keep it from leaning toward Oakland.”
Clearly more tests are need, but there is not enough money left from the $6.4 billion project to perform them.
Chief project engineer Brian Maroney thinks heightened stress and manufacturing problems could be to blame.
But corrosion expert Charles McMahon, a professor emeritus at the University of Pennsylvania told the Chronicle photos of the cracking indicates hydrogen.
“This is hydrogen-induced cracking,” McMahon told the Chronicle.
“It’s pretty clear that the guys who were in charge of this thing are clueless when it comes to selecting the right materials,” McMahon added. “They had no idea what they were doing. The whole thing is a disaster.”
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