AASHTO Journal, 16 October 2015
The California Department of Transportation received approval to construct a pair of models – one of calculations, one physical – to determine the best way to protect more than 400 of the 25-foot-tall anchor rods at the base of the San Francisco-Oakland Bay Bridge span’s signature tower.
The three-person Toll Bridge Program Oversight Committee on Oct. 13 OK’d recommendations from a panel of bridge experts that included Federal Highway Administration engineers, international scholars and members of the U.S. Academy of Sciences and Engineering.
“You can’t overstate the value of us listening to the experts,” said Caltrans Director Malcolm Dougherty, who is one of the oversight committee members. “We took a step closer to resolving definitively and permanently the issues at the tower base.”
The other two oversight members are Chairman Steve Heminger, the executive director of the Bay Area Toll Authority, and Will Kempton, executive director of the California Transportation Commission.
Last fall, Caltrans inspectors found the contractor had not properly sealed the steel rods embedded in the tower’s foundation, failing to protect them against the elements.
The oversight committee solicited help of the international experts in June, and that panel assessed what actions should be taken to protect the rods that anchor the tower to its foundation. Its recommendations were summarized in the committee’s Oct. 13 meeting documents.
Last month, the oversight group had also voted to penalize contractor American Bridge/Fluor $11 million for a July 2013 failure of rods intended to help the bridge’s eastern span survive an earthquake.
In its latest action on 400 anchor rods, Caltrans said the oversight committee declined to adopt a repair plan that could have cost more than $15 million, with members saying they wanted more information to make the most prudent resolution possible.
Recommendations that were adopted included rendering a mathematical analysis of how the Bay Bridge tower would perform in a major seismic event, as well as full-scale construction model in which 17-foot-long steel rods would be cemented into sleeves mimicking their placement in the bridge.
