SAN FRANCISCO (CBS SF) -- The old eastern span of the Bay Bridge is closing for good Wednesday evening but won't be disappearing from view -- bridge officials say it will take around three years to take apart and remove the seismically unsafe span.
The old cantilever bridge, built in 1936 to connect Oakland to Yerba Buena Island, has been slated for replacement since the 1989 Loma Prieta earthquake collapsed a section of the span's upper deck.
After years of delays, it is finally closing to traffic forever at 8 p.m. Wednesday and will be replaced by a new self-anchored suspension bridge opening next week just to the north of the old span.
But while a building on land can be demolished fairly quickly, the bridge's location over the Bay requires the painstaking removal of the span piece by piece.
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Bay Bridge spokesman Andrew Gordon said the demolition of the old span can begin "as soon as traffic is off the bridge" and should be completed by 2016.
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Crews will begin taking apart the bridge from west to east, starting with the temporary S-curve installed in 2009 and then moving east along the cantilever section toward Oakland, Gordon said.
The project will use the plans for the old bridge to help crews take it apart, Gordon said.
"We're studying the blueprints of how the bridge got built to use that as a guide to how to basically take it apart," he said.
Bridge officials say the demolition work must be done with great care because it will be performed within close proximity of moving vehicle traffic on the new span, as well as a new bike and pedestrian pathway on the bridge.
Gordon said Silverado Contractors Inc. and California Engineering Contractors Inc. are carrying out the project.
The two East Bay-based companies both have experience working on the Bay Bridge project, as well as the replacement of the old Carquinez Bridge near Vallejo.
Metropolitan Transportation Commission spokesman John Goodwin said authorities do not anticipate drivers to be distracted by the dismantling work, citing the Carquinez Bridge project as a similar example.
"To a large degree, people are used to it," Goodwin said. "It's pretty slow work, cutting loose one piece at a time, so you're not seeing an entire section of bridge coming down at one time."
He said the current cost forecast for the demolition project is $233.7 million, which is part of the overall $6.4 billion cost of the bridge replacement.
Goodwin also cautioned Bay Area residents to not be impatient with the dismantling of the old bridge.
"It's going be a long, slow, laborious process under the best of circumstances," he said.
More information about the replacement of the eastern span can be found online at www.baybridgeinfo.org.
(Copyright 2013 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed)
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