Following up on the successful implosion of the largest pier on the old eastern span of the Bay Bridge, Caltrans is seeking to demolish 15 remaining piers the same way at a cost of $130 million in what is expected to be the final steps of removing the old bridge.
Caltrans this afternoon will ask the Toll Bridge Oversight Committee, the three-member governing body for the Bay Bridge retrofit project, to approve a contract to a joint venture between construction and engineering firms Kiewit and Manson, Caltrans officials said today.
The implosion of Pier E3 in November demolished the pier in a matter of six seconds, collapsing the pulverized concrete into the pier’s own buried cavities and burying it at the bottom of the Bay.
November was chosen because of an anticipated minimal number of marine mammals in the area, although crews still kept an eye out for seals, porpoises and sea lions so they weren’t disturbed by the detonation of thousands of small explosives.
Caltrans officials said the method was not only more cost effective than mechanically demolishing the pier, but more environmentally friendly as well. Surrounding the pier with a dam, pumping the water out and dismantling the pier with construction equipment would take months and disrupt area wildlife in the process.
After the implosion, Caltrans declared it a success, saying that a “bubble curtain” of air around the pier successfully contained the implosion and that impact to protected wildlife was minimal, though some fish were killed in the process as expected.
So Caltrans now wants to move forward in using similar methods to demolish the remaining piers. If the contract is approved and Caltrans is granted the necessary permits from federal and state agencies, the next two piers would be removed this fall, followed by six more in the fall of 2017 and seven more in the fall of 2018.
Scott Morris, Bay City News