California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (4)

October 2008 (38.043 deg, -122.122 deg.) Benicia-Martinez Bridges

I was looking for a photo of the Benicia-Martinez Railway Bridge but all I could find was this photo from inside the Amtrak train going over the railway bridge. From the window is the new (2007) northbound Benicia-Martinez Highway Bridge, and Suisin Bay (with the mothballed fleet) obscured by the rising sun.

Amtrak's Capitol Corridor starts in the Sierra Foothills in Auburn, crosses the Straits on the old railway bridge, and then jogs to the west into Richmond before turning south and going all the way to San Jose. Passengers wishing to go to San Francisco get off in Emeryville where a bus takes them over the Bay Bridge.

California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (4) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (3)

1999 (38.043 deg, -122.122 deg.) Benicia-Martinez Bridges

The southbound Benicia Martinez Bridge is composed of seven 528 ft long truss spans. The seismic retrofit would have required extensive work to strengthen the piers and foundations for the resulting large inertia force. The use of 10 ft diameter friction pendulum bearings reduced the earthquake forces being carried by the piers which reduced the cost of the retrofit. 

Each bearing was tested on the giant shake table at UC San Diego before it was placed between the superstructure and substructure. Jacking platforms were built onto the top of the piers to allow for easy replacement of bearings, if required after an earthquake.

California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (2)

1999 (38.043 deg, -122.122 deg.) Benicia-Martinez Bridges

We have been looking at the toll bridges along San Francisco Bay. On the west side of the Benicia Martinez Railway Bridge is this 1.2 mile long truss bridge that was built in 1962. I am very familiar with this bridge because of the giant friction pendulum bearings that we used for it's seismic retrofit and also because I used to drive over it a lot when my son was going to UC Santa Cruz. We'll take a look at the bearings tomorrow.

Part of the pleasure of driving over this bridge is seeing the old mothballed ships from WWll sitting to the east in Suisin Bay. There's a Sam Peckipah movie, "The Killer Elite" where the big fight scene at the end of the movie takes place on these ships. I'll see if I can find a photo of the fleet.

I'll also see if I can find a better photo of the railroad bridge which is much older (build in 1930). I believe there is a lift span at the center of the bridge which may be permanently closed. I know the bridge is still used because the Amtrak trains take it a dozen times a day between Sacramento and San Francisco (actually to Emeryville and then a bus ride into San Francisco).


My photo has a reddish tint perhaps because it was originally on film and scanned at a later date. It's tough to find a good place to photograph these bridges. The Sacramento River eventually goes into Carquinez Straits, but there are so many islands and tributaries that I would get lost trying to paddle to it in my kayak.

California's Bridges: Benicia-Martinez Bridges across the Carquinez Straits (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.