Sunday, May 12, 2013

What's Going to Happen to the New Span of the Oakland-San Francisco Bay Bridge When an Earthquake Hits?

Mary Theroux explains:

I have written before about the amazing saga of the new span for the Oakland-San Francisco Bay Bridge, now 24 years and $6.4 billion in the making...with no end in sight. A full account of its background can be found here.
The “signature design” never before built and of dubious seismic stability in one of the Continental U.S.’s most earthquake-prone areas, now faces a new round of problems:2,300 bolts holding it together are likely to fail.
Bolts that the agency building the bridge had itself banned from use on bridges.

Generic specifications are for a run-of-the-mill bridge, and this bridge is not run-of-the-mill.But rules—when you’re the government and they’re your rules—are made to be broken. As explained by the Director of the California Department of Transportation (Caltrans):
Indeed it’s not. It’s “art,” and pesky notions like safety and engineering principles must simply understand.
Almost from the get-go, safety and engineering have taken a backseat as politicians hijacked the bridge-replacement process. Under their guidance, designers came up with an asymmetrical self-anchored suspension bridge with unique cabling features—a design that has never been built, but nevertheless carried the politicized vote of approval.
An architect serving on the panel offered this explanation for the final vote:
“The novelty factor kicked in, especially with the engineers. And everyone was getting a bit tired by then.”
Fast-forward 15 years: the resulting bridge is supposed to be opened for traffic this September, with a final price tag somewhere north of $6.4 billion—nearly five times that projected. The general perception is that if it doesn’t open on schedule it will be a black eye for somebody—though I’m not sure for whom, since none of the original political gamesmen seems to be standing up—and one wonders if safety will now, finally, be allowed to trump politics.
An earlier safety whistle blown was quickly silenced. The Sacramento Bee conducted an exhaustive investigation, reviewing 50,000 technical files, and consulting with the world’s leading experts in bridge construction, to reveal significant questions regarding the safety of the bridge’s concrete foundations.
Questions that have never been answered.

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