As months have gone by on the seemingly endless construction of the Bay Bridge's new eastern span, the structure has gradually started to look more and more like something actually resembling a bridge.
This week, Caltrans construction crews are going to begin the installation of the suspension cable that should be a big step forward in giving the bridge its shape.
The cable will be supported by the eastern span's single tower in an unconventional manner. The cable will anchor on the Oakland side and run over the tower to Treasure Island, where it will loop back around, travel again over the tower and then finally anchor its other end back on the mainland. Even though the end result is going to look like four separate cables, it's really just a single, nearly mile-long cable--the longest of its type used for bridge construction anywhere in the world.
Once the main cables are installed, which Caltrans expects to happen by the end of the week, workers will begin hanging the 137, 2.5 inch, 5,291 ton cable, that will hold up the bridge's deck. However, the way these cables will be attached is something revolutionary in the world of bridge construction.
"This is not your grandfather's suspension bridge. We're not going to pull this cable one-by-one," said," Caltrans spokesman Bart Ney told CBS San Francisco. "This bridge is special. We're going to pull whole bundles of wire."
The San Francisco Chronicle reports:
When all the strands are strung, and placed in a predetermined order, crews will use compacting devices to crunch them into a single steel cable. It will be coated, wrapped and treated with a protective solution. Then vertical suspender cables will be draped from the main cable and connected to the bridge deck. Once that work is done, crews will remove the temporary steel trestle supporting the deck, and it should stand on its own.
The job is expected to take up to six months, Ney said, though the contractor believes it can be completed faster.
"Everything that we're doing here is the first time," Caltrans Public Information Officer Kenyon Johnson told the San Jose Mercury News. "It's a unique experience...we have a lot of designs that have never been done before."
The entire project, which is years a billions of dollars over budget largely owing to the California Department of Transportation's battles with the U.S. Navy (and Willie Brown) over the proposed design for the bridge and delays in receiving necessary shipments of steel from a Chinese manufacturer, is expected to be completed in 2013 with a price tag just north of $6 billion.