As if we didn’t have enough problems on our cars with bolts stripping threads, cracking, rounding off, breaking, now the San Francisco Chronicle is reporting the new SF-Oakland Bay Bridge is having problems with its own bolts!
"The new Bay Bridge eastern span has more than 1,200 bolts made from galvanized steel that is virtually identical to a high-strength alloy that a nationwide group of transportation officials banned for bridge use because it can crack over time, The Chronicle has learned.
The bolts serve vital roles on the new span: They anchor structures that are supposed to keep the bridge stable in an earthquake, they band the main cables together, hold the cables down at the top of the tower and bind them to the road decks."
You would think that after the Titanic tragedy…engineers would have had enough time come up with a super strong alloy for both rivets and bolts. I know it’s not a simple task but it has been over 100 years.
I guess its a compromise @missileman between bolt strength, brittleness, and cost. This bridge design started 24 years ago, after a big earthquake we had here in the SF Bay area that knocked down a section of the old bridge. You may remember it from news reports, back in 1989. For years and years the two cities involved, the mayors mostly – SF and Oakland – argued about the design, each wanted a certain bridge function and appearance they liked, finally they decided on something they both liked, but I guess the bolt specs fell off the table during the final design process. Seems amazing, when they had from 1989 to 2013 to get it right, but when city politics gets involved with engineering, it appears anything can happen. And who am I to talk anyway. What do I know about the alloys used in making bolts? Nothing. Just an opinion is all.