A temporary double-deck roadway is taking shape just east of Yerba Buena Island. It will be a detour for four years while that section of the old bridge is demolished, replaced with the new side-by-side roadway and connected with the new suspension bridge.
"Our biggest challenge on the Bay Bridge is that we always have to keep traffic moving while we completely replace it in the same footprint that it exists in," said Bart Ney, Spokesman for Caltrans.
Caltrans took us out on one of its boats for a look at the work from below. The free-standing columns mark the path of the temporary bypass.
"The curves will be eased so you can make it through at 40 miles per hour on both decks, but it won't be the straight shot you've had before obviously because we want the best alignment for the new bridge," said Ney.
Spokesman Bart Ney says the bypass will look much like what exists now and has comparable seismic safety.
The other massive project about to begin on the other side of the bridge is work on the new suspension bridge. The contractor has to build a temporary structure to support the new bridge deck while the tower and suspension cables are constructed.
"So people will start seeing a steel truss structure going up out there. That is the not the signature span that we're going to build. Because of the nature of this bridge, we have to put a lot of steel out there and you're going to see it erected this year," said Ney.
It doesn't look like much now, but they've started on the foundation of the 525-foot tall bridge tower. It will be the tallest self-anchored suspension bridge in the world.
Caltrans engineer Rick Morrow is the project manager.
"That particular foundation is anchored into bedrock there on the edge of Yerba Buena Island and is designed to support the full weight of the bridge and tower that will be set on top of it," said Rick Morrow from Caltrans.
The suspension bridge will begin where the new eastern skyway now ends. The steel bridge roadway, like these white segments, is now being fabricated in China. That contractor is also having to build a special barge crane to lift the steel segments into place.
"Some of those segments are so large that there really isn't anything available locally to be able to lift the segments into place," said Morrow.
In 2007, the white segment of the westbound bridge, leading into Yuba Buena Island's tunnel, had to be replaced. Last Labor Day weekend, the bridge was closed so that that new piece could be rolled into place.
There will be a similar process next year to connect the temporary bypass, this detour, with the existing structure. They're going to have to cut out a section of the bridge and roll in a new connector section, but there will be a reprieve from bridge closures until next year, and all of this is on schedule to be completed on time in 2013.
