Experts wonder why steel beam on the Bay Bridge cracked

SACRAMENTO — A cracked steel beam that compromised the safety of the Bay Bridge was repaired in miraculous time, and the span reopened to commuters Tuesday morning. But the speedy fix didn't bring an end to questions about the crack itself: how it materialized, how it was repaired, and whether the bridge holds other cracks like it still waiting to be found.

The crack was found by Caltrans inspectors Saturday during a routine safety inspection. The inspection was timed to coincide with the planned weekend closure of the bridge to allow contractor C.C. Myers Inc. of Rancho Cordova to slide a new bridge section into place as part of the replacement of the bridge's eastern span.

The bridge must be inspected every two years, according to Federal Highway Administration rules. The last inspection in 2007 — also on Labor Day weekend — covered the same section of bridge but turned up no cracks, according to Caltrans.

California Transportation Department officials say they don't know what caused the crack, which was discovered in a bridge part called an eyebar, a load-bearing structure that resembles a link in a bicycle chain.

"You've got to keep in mind, this is an almost 80-year-old bridge," said Caltrans spokesman Bart Ney. "It doesn't appear to be from any type of collision or anything like that. It's just something that happened, and when you find it, you have to repair it."

Caltrans immediately called on the C.C. Myers company to help design and install a fix. This resulted in construction of two giant steel boxlike structures, called saddles, to brace the eyebar on each end.

The saddles, which weigh 6,000 pounds each, are joined by high-strength rods that compress the eyebar structure.

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