The federal government’s chief bridge engineer voiced concern that “rogue plate” — steel that does not meet Caltrans’ standards – is being used to seismically reinforce the tower of the new Bay Bridge, according to documents disclosed under the state’s Public Records Act.
“We think it’s prudent for Caltrans to look into this further,” Brian Kozy, the Federal Highway Adminstration official, told Caltrans officials in a June email, but added, there’s no “immediate safety concern.”
Kozy cited independent test results on a four-inch thick piece of steel taken from the system designed to bolster the 525-foot tower at its base.
Testing showed that three out of four samples taken from the steel stretched too readily when exposed to quake-level stress. The worry is not outright failure, but a permanent weakening as the result of a quake.
For Kozy, the worse-case scenario explanation for the bad test results is that Caltrans unknowingly accepted “rogue plate” that did not meet its specifications.
The issue is just the latest in a string of problems on the $6.4 billion eastern span project, which includes cracked bolts, flawed welds and a foundation flooded with corrosive saltwater.
Brian Maroney, the chief bridge engineer on the project, said Caltrans did a new review of the steel’s quality control documentation, created before it was installed.
The review concluded that all the sampled material met Caltrans’ standards, including its ability to handle 50,000 pounds-per-square-inch stress. But the test data suggests that the steel only meets a 36,000 pounds-per-square inch standard, a lower grade.
Maroney emphasized that the steel at issue is not intended to bear weight during normal conditions, only to channel and control the twisting and upheaval of a massive earthquake.
“The only reason this thing is there is for a seismic event,” said Maroney, who says the four-inch thick plates help bind the four-legged tower together to restrain…