Following on some comments last week by a retired engineer who says that Caltrans "fell on its face" with regard to the steel-bolts fiasco, it's come to light that there are some 1,200 bolts in total that might need to be replaced on the new eastern span of the Bay Bridge. And though Caltrans has not said that this will delay the scheduled Labor Day opening of the bridge, we're starting to think that it might.
SFGate is reporting that Caltrans ordered 1,200 galvanized steel fasteners made of the same metal used in the 32 bolts that were found to be cracked. They're testing 192 bolts for possible future failure, but what of these other 1,000?
Retired Bechtel metallurgist Yun Chung offered up a 32-page report last week stating that Caltrans engineers "were ignorant to the threat of hydrogen embrittlement a process in which high strength metals, such as steel, become brittle and fracture due to hydrogen exposure." The type of steel used in manufacturing the bolts, he said, was more hard on the outside than is required in Caltrans own specifications, and that the state's engineers were only focused on hydrogen exposure during the manufacturing, and not on exposure to the elements, which he believes caused them to become brittle and snap. Chung's findings have been vetted by other experts, who agree.
In any event, this is a huge PR nightmare for Caltrans, not to mention a potential major setback in the completion of the bridge. Stay tuned for more news this week.
Previously: The New Bay Bridge Span Is Seismically Shaky
