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http://www.sfgate.com/bayarea/article/Bay-Bridge-troubles-began-with-design-4616774.php#photo-4819308

The team designing the new Bay Bridge eastern span had a problem.

Pressure was building to move forward on what would become the most expensive public works project in California history, but Caltrans' in-house steel experts reviewing plans for the new bridge had spotted what they believed was a major flaw.

Among the more than 1,000 pages, they pointed to a single sheet that called for the use of a particular type of high-strength steel bolt coated in molten zinc, a process known as galvanization. Such bolts, the experts warned, were prone to cracking in a moist marine environment such as San Francisco Bay and shouldn't be used.

It turned out that the bridge design called for thousands of other bolts and rods made of that same kind of steel - fasteners strong enough to enable the unconventional span to resist the everyday vibrations created by big rigs and the far stronger forces unleashed in a large earthquake.

In a flurry of deadline-driven decisions over the next few weeks in early 2003, the design team from the firm T.Y. Lin International and Caltrans officials made adjustments in response to the experts' warnings. But they also took their cue from a bolt manufacturer - which said Caltrans had used the same kind of steel on an earlier, high-profile bridge project - and opted to install more than 2,300 galvanized, hardened fasteners on the eastern span.

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