Newest Bay Bridge Problem Poses Threat to Its “Sacred Ground” in an Earthquake

Friday, May 16, 2014
New Bay Bridge, on the right (photo: Ezra Shaw, Getty Images)

There have been no shortage of stories about problems with the San Francisco-Oakland Bay Bridge's   new $6.4 billion span that opened last September, some linked to suspect manufacturing of parts in China and others to questionable design and construction mistakes.

After a while, as problems are addressed and others are minimized, the shear number of them can enure observers to the business-as-usual difficulties involved in a mega-project like the bridge. But when California Department of Transportation (Caltrans) senior engineer Brian Maroney expresses fear that bad bolts pose a threat to the “sacred ground” of the bridge's structure, people perk up.

Maroney confirmed to the San Francisco Chronicle this week that more than 200 steel rods anchoring the main cable and tower on the bridge's new east span could be at risk in an earthquake. The rods have shifted since first installed and are close to metal plates with sharp edges nearby.

“This is sacred ground,” Maroney said. “The cable and the tower are the backbone and the spine, critical elements to this bridge. I don't want to be worrying about the cable system.”

Nobody does, although some people have been worrying about it longer than others. Caltrans apparently learned of the problem when it reinspected the bridge's bolts following the snapping of a bunch of other rods last year. While Caltrans knew of the latest problem months ago, the Metropolitan Transportation Commission (MTC), which oversees the project and will be taking operational control of the structure later this year, only learned about it a month ago, the Chronicle said.

The issue was not on a list of problems Caltrans submitted to the commission on May 6. It first became public knowledge Tuesday when MTC deputy executive director Andrew B. Fremier briefed members of the Bay Area Toll Authority. In an interview with the Sacramento Bee, Fremier characterized the problem as important but not urgent.

A survey by Caltrans found that 205 of 274 key rods are way off center. At this point, it's uncertain how to readjust them and prevent contact with the sharp-edge plates. Two of the rods are already touching them and it's thought that vibrations and shifting in an earthquake could destabilize the bridge.

Bridge engineering expert Arthur Hucklebridge, professor emeritus from Case Western Reserve, told the Bee that these types of problems aren't unheard of and are acceptable in some instances. The fact that this one is being addressed suggested to him that it was, in the Bee's words, “relatively extreme.”

Fremier said he thought the problem could be solved by the end of the year and maybe cost somewhere around $2 million.

Last month, news reports publicized problems with rusting bolts caused by leaks in bridge chambers that were supposed to be watertight.

–Ken Broder


To Learn More:

Bay Bridge Rods Helping Hold Main Cable Are Misaligned, May Need Repair (by Charles Piller, Sacramento Bee)

New Bay Bridge Defect Could Be Trouble in Earthquake (by Jaxon Van Derbeken, San Francisco Chronicle)

New Bay Bridge Has Leaks, Rust and Weld Defects but No Independent Review (by Ken Broder, AllGov California)

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