BRIDGE CONSTRUCTION: Experts recommend interim Bay Bridge fix

With bearings shimmed, bridge could open before permanent bolt fix

Bridges News TBPOC August 14, 2013
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The California Toll Bridge Program Oversight Committee (TBPOC) has received a report from the Federal Highway Administration in which the federal agency concludes that installing temporary seismic elements will make the new East Span of the San Francisco-Oakland Bay Bridge safe for traffic and should be put in place as quickly as possible. This plan involves inserting large steel plates, known as shims, into each of four bearings, enhancing their ability to safely distribute energy during an earthquake.

 

The TBPOC in July asked federal highway officials to analyze the shim installation plan to assess its viability to allow the new East Span to open prior to the permanent retrofit for broken bolts on the easternmost pier of the self-anchored suspension portion of the new bridge. Federal officials recommend adopting that plan. This recommendation is consistent with that of internationally known bridge designers Dr. Peter Taylor of Buckland & Taylor Ltd. in North Vancouver, B.C., and Dr. John Kulicki of Modjeski and Masters in Mechanicsburg, Pa., who submitted separate analyses of the shimming strategy originally advocated by the Toll Bridge Seismic Safety Peer Review Panel. Each of these independent reports can be viewed online at mtc.ca.gov and at baybridgeinfo.org.

 

“Safety has always been the driving factor for any decision related to this lifeline bridge, and these reports confirm that the temporary fix could allow us to safely move traffic while work continues on a permanent retrofit,” said Steve Heminger, chairman of the TBPOC. “We will meet in a public session to discuss this important information and to announce the opening date for the Bay Bridge.”

 

At the July meeting, the TBPOC concluded its investigation into the breakage of a batch of large bolts on the eastern span of the Bay Bridge and recommended that the bridge opening be postponed from the previously announced opening on Labor Day 2013 until further engineering work could be completed and considered.

 

The TBPOC will hold a public meeting on Thursday, Aug. 15, at which time these reports will be discussed and the opening date for the new East Span will be announced. The meeting will be audiocast at mtc.ca.gov/meetings/schedule.

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