Sunday, April 20, 2014

San Joaquin County, California Bridges: BNSF Bacon Island Bridge across the Middle River

April 2014 (37.93979 Degrees-121.53310 Degrees) Bacon Island Bridge
Three Hugo Abt designed bascule bridges carry the BNSF Railway across rivers in San Joaquin County. The Woodward Island Bridge across the Old River was studied in February and can be seen (in the distance) in the photo above. The Bacon Island Bridge across the Middle River will be studied today. We'll look at the 3rd Hugo Abt Bascule Bridge over the San Joaquin River next week.
The BNSF - Bacon Island Bridge is part of a long concrete trestle that carries the BNSF tracks over a cut made between Woodward and Bacon Islands. The BNSF - Woodward Island Bridge is at the western end of the trestle. All of the bascule bridges were built by the American Bridge Company between 1928 and 1930.
On an Abt bridge, a large weight is suspended from a tall steel truss. As the weight swings down, a shorter truss folds, which lifts up the adjacent steel girder span.  A photo of an Abt bridge in the open position is provided by the HistoricBridges Website

According to 'Movable Bridge Engineering,' the vertical clearance for the Bacon Island Bridge is 11 ft in the closed position. However, whether this bridge is still being opened is questionable. 
Railroad bridge engineers have little interest in bridge aesthetics, which results in their bridges having a very utilitarian appearance. Apparently, a lack of concern about aesthetics results in a strong aesthetic statement. 

These bridges carry freight and passenger trains across the California Delta.
Creative Commons License
San Joaquin County, California Bridges: BNSF Bacon Island Bridge across the Middle River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Saturday, April 19, 2014

San Joaquin County, California Bridges: South Bacon Island Road Bridge across the Middle River

April 2014 (37.95608 Degrees-121.52795 Degrees) South Bacon Island Road Bridge
A second South Bacon Island Road Bridge (29C0108) crosses the Middle River a little south of yesterday's bridge. The current bridge is a 975 ft long concrete trestle with a 120 ft long steel girder swing bridge across the channel that was built in 1995. 
A previous bridge had been built in 1905 at this site. It was photographed by the Library of Congress and documented for its historic significance: 'The Bacon Island Road Bridge is the oldest highway swing span bridge in California. It is important in local history for its relation to agricultural and economic development in the Sacramento-San Joaquin Delta. It is the work of an unknown bridge company which utilized Carnegie Steel and U.S. Steel Company components.'
Creative Commons License
San Joaquin County, California Bridges: South Bacon Island Road Bridge across the Middle River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.