A bridge engineering expert told a Bay Area transportation panel today that a short-term fix could allow the new eastern span of the Bay Bridge to open on schedule by Labor Day after all.
Frieder Seible’s comments surprised members of the Metropolitan Transportation Commission’s Bay Area Toll Authority as well as transportation officials who are overseeing the $6.4 billion project to build the new span, which is aimed at being safer during an earthquake than the existing span built 77 years ago.
Seible’s proposal came only two days after those officials—MTC Executive Director Steve Heminger, Caltrans Director Malcolm Dougherty and California Transportation Commission Executive Director Andre Boutros—announced that the bridge opening will have to be delayed until December to fix problems with failed anchor bolts on a pier along the new span just east of Yerba Buena Island.
Transportation officials learned in March that 32 of the 96 bolts installed on the pier had failed, popping out several inches after being tightened. They were manufactured in Ohio in 2008.
The bolts are holding in place seismic safety devices known as shear keys that help prevent swaying during an earthquake.
Transportation officials are addressing the problem by covering the broken rods with an exterior saddle and cable system that will be encased in concrete. Heminger said today that the repair work probably will cost about $20 million.
But Seible, a emeritus dean at the University of California at San Diego who chairs the Toll Bridge Program Seismic Safety Peer Review Panel, recommended today that transportation officials pursue a temporary fix that would use wedges or shims that would turn bearings into shear keys that would prevent movement during an earthquake.
“We could still achieve full seismic safety for the bridge and we could do it in a month,” Seible said.
He said it’s important to open the new span as soon as possible because there’s “little confidence” the existing span, which was damaged in the 1989 Loma Prieta earthquake, could withstand even a moderate temblor.
“We don’t know when the next earthquake could occur,” Seible said, “It could occur any day.”
Several members of the Bay Area Toll Authority, which consists of local elected officials, said they’re in favor of exploring the temporary fix.
Rohnert Park City Councilman Jake McKenzie, who represents Sonoma County, said, “If we can expedite the opening, I’m here to support it.”
After today’s three-hour hearing, Heminger told reporters at a briefing that he’d previously heard of the concept of using shims to turn bearings into shear keys but today was the first time he found out that Seible has prepared an engineering concept that can be implemented soon.
He said, “It merits vetting and will discern if it can happen soon.”
Dougherty said, “It’s a developing conversation that will be subjected to review and we’ll give it due diligence.”
Jeff Shuttleworth, Bay City News