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A Bridge Too Weak? 

A UC Berkeley professor believes the unique new Bay Bridge design is fatally flawed

Wednesday, Mar 17 2004
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After hearing a lengthy presentation from Astaneh in 1999, Brown held a news conference the next day to announce his opposition to the single-tower design, saying he was convinced it was unsafe. Although critics accused him of posturing, suggesting that Brown's agenda was to torpedo any design that might interfere with plans by politically connected friends to develop part of Yerba Buena Island, the mayor never recanted his safety concerns.

With a boost from Brown, Astaneh was dispatched to Washington, D.C., where he gained an audience with Clinton administration staffers including a high-level assistant to then-Transportation Secretary Rodney Slater. With Brown and the Navy resisting the self-anchored design on one side, and Caltrans, the MTC, and Gov. Davis pushing for the bridge project to move forward on the other, the U.S. Army Corps of Engineers was called in to study the issue.

Although the Army engineers gave their seal of approval to the bridge design, a voluminous Corps report issued in October 2000 can hardly be classified as a ringing endorsement. About the best the engineers could say about the seismic concerns Astaneh had raised was that "the design team is moving along a path to design a bridge that meets the seismic performance criteria" established by the MTC.

The Army Corps concluded that the bridge was not designed for a "maximum credible earthquake," or MCE, along either of the two nearby fault lines. An MCE denotes the most severe ground motion considered possible at a given location. Scientists say the San Andreas fault, which runs beneath the peninsula on which San Francisco rests, is capable of producing an MCE of 8.0 on the Richter scale, and that the Hayward fault, which passes beneath the Oakland hills within five miles of the bridge, could produce a 7.25 shaker. By comparison, the Loma Prieta quake, which, among other things, collapsed the Cypress Freeway in West Oakland, killing 42 people, and killed another person on the Bay Bridge, measured 7.1. But its epicenter was 60 miles south of the bridge; experts say damage to the span would have been worse had the epicenter been closer.

Caltrans and the new Bay Bridge's designers say their plan incorporates the highest seismic safeguards. But they based their calculations on a different model, called the "safety evaluation earthquake." SEE places more emphasis on the probability of a major quake occurring during the bridge's anticipated 150-year life span.

The Army engineers didn't take a position on which is the better approach. Neither did they pass judgment on the self-anchored bridge's seismic characteristics compared to other designs.

"On a scale of A to F weighing seismic safety reliability and cost efficiency, where A is the best system and F is unacceptable, how would you rate the standard anchored suspension bridge and the proposed self-anchored, asymmetric single tower, pile-supported East Span replacement?" reads a question posed in an appendix to the Army Corps report. The engineers' response: "The rating requested in this question is outside the current scope of work."

The MTC board voted 11-1 in favor of the self-anchored design recommended by its advisory panel. Then-Oakland Mayor Elihu Harris was the lone dissenter, at the time citing cost and aesthetics as his primary objections. His successor, Jerry Brown, took a similar position. Looking back, Harris now says, "I think [the MTC] was too eager to get on with it. And it was too dismissive of Astaneh."


Although his expertise remains highly sought-after by others, Astaneh says he has paid a price as the bridge's chief naysayer.

After he spoke out, Caltrans halted payments on a $500,000 grant to the university's engineering department for work being done under Astaneh's supervision. "Caltrans is not good at tolerating dissent," he says. Caltrans denies any retaliation, saying budget cuts forced it to scale back spending for academic research.

Inevitably, Astaneh's stance has been labeled as sour grapes by some who note that a competing bridge design that he and R. Gary Black submitted was among those that the MTC panel rejected. The suggestion draws a chuckle from the professor. "Oh, come on," he says. "More than 275,000 people a day cross that bridge. We're talking about people's lives." As for his design, he insists, "We were very proud of it, but from my perspective it was as much an exercise for my students as anything. I never expected that it would be chosen, and I certainly wasn't heartbroken over it when it wasn't."

Even now, he says, if the governor or someone else were to ask, he would recommend scrapping the self-anchored span and finding another way to link Yerba Buena Island and the East Bay, even if it meant merely extending the skyway. But he isn't on a crusade.

"My friends and my wife have said, 'Why not just be quiet about the bridge?' But it's very simple. If, God forbid, a tragedy should occur on that span someday, I don't want anyone to say I didn't do enough to speak up."

About The Author

Ron Russell

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