Thursday, July 31, 2014

San Francisco County, California Bridges: Illinois Street Bridge across Islais Creek

July 2014 (37.74740, -122.38617) Illinois Street Bridge
The last movable bridge in San Francisco County is the Illinois Street Bridge. Sitting one block away from yesterday's Third Street Bridge, it is a single leaf bascule bridge without counterweights. Instead, the bridge is raised and lowered by hydraulic cylinders that pull and push on lever arms connected to the steel deck. Perhaps this is the future for bascule bridges? It was built in 2006 by Shimmick Construction and others. It doesn't have a county bridge number because it's owned by Bay Area Rapid Transit (BART). It was built between San Francisco Port's north and south terminals, mainly for trucks, but also with sidewalks for bikes and pedestrians and with rails for freight trains.  
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San Francisco County, California Bridges: Illinois Street Bridge across Islais Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Wednesday, July 30, 2014

San Francisco County, California Bridges: Third Street Bridge across Islais Creek

July 2014 (37.74694 Degrees, -122.38694 Degrees) Third Street Bridge
Today's bridge is also on Third Street but several miles to the south across Islais Creek. It's called the Levon Hagop Nishkian Bridge (34C0024) after the senior member of a family of civil engineers that have practiced in San Francisco for the last 100 years. It is a double leaf bascule bridge that was built in 1945. Some nice photos of Islais Creek and the bridge (taken just after the Second World War) are on this website. An unusual aspect of the bridge is the art deco style of the bridge tender's house and of the shiny silver-painted covers over the arms supporting the counterweights, which are under the bridge. The bridge also has overhead catenary cables and tracks for the trolleys (owned by Caltrain) that cross the bridge.
Creative Commons License
San Francisco County, California Bridges: Third Street Bridge across Islais Creek by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.