Willamette River Crossings: Union Street Bridge in Salem, Oregon

July 2017 (44.947, -123.0418) Union Street Railroad Bridge

Continuing downstream along the Willamette River we arrived at the Union Street Railroad Bridge in Salem, Oregon. This bridge (like last week's Van Buren Street Bridge) is from 1913 and was built by the Southern Pacific Railroad. It changed hands several times before it was finally sold by the Union Pacific Railroad to the City of Salem in 2003.  The bridge was added to the National Register of Historic Places in 2006 and converted to a pedestrian and bicycle bridge in 2009.

This structure is a vertical lift bridge that uses a patented system developed by the designers Waddel and Harrington. The top of the towers are 65 ft above the trusses for a total height of about 100 ft. The towers stopped working in the 1980s and the mechanism (and operator's house) was removed soon afterwards (see bottom photo).

This longitudinally asymmetric five span bridge sits on concrete piers that were designed to be high enough to keep the track five feet above the highest recorded flood water on the Willamette. There is a 134 ft long lift span (shown in photo below) and four Pratt truss spans for total length of 755 feet. There is also an 850 ft long timber trestle on the west end.

This railroad bridge (which carried it's last train in the 1990's) underwent considerable modification before it began carrying pedestrians. Lead based paint, ballast and the track all had to be removed. Besides being redesigned as a pedestrian bridge, it was also redesigned to carry emergency vehicles.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

San Joaquin County, California Bridges: Mossdale Railroad Bridge across the San Joaquin River

April 2014 (37.78749 Degrees, -121.30794 Degrees) Mossdale Railroad Bridge

In the town of Lathrop (north of Ripon and east of Tracy) are seven bridges including several historic structures across the San Joaquin River. Today's bridge is the Union Pacific Mossdale Railroad Bridge. It's composed of a six panel, riveted Warren truss with a center span that was once raised and lowered by the towers on the side spans. The river is too shallow at this location to carry large boats today. Besides, the bridge has 22 ft vertical clearance in the closed position to allow for the passage of vessels. The bridge is 526 ft long with a 110 ft long center span. This is the third railroad bridge at this site, the current bridge was built in 1946, and it is registered as a California Historical Site (780-7). 

There is a lot of good information about this bridge. The Trainorders website discusses the history of the bridge, disasters that occurred on the railroad line (between Mococo and Lathrop), and the different trains that it carried. 

Apparently, the first bridge at this site (built in 1869) was the final link of the Transcontinental Railroad. Before it was completed passengers had to get off in Lathrop and take a ferry across the river before boarding another train on the opposite side.

San Joaquin County, California Bridges: Mossdale Railroad Bridge across the San Joaquin River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Solano County, California Bridges: Rio Vista Bridge across the Sacramento River

January 2014 (38.15899 Degrees, -121.68393 Degrees) Rio Vista Bridge 

Continuing to the east of the Benicia Martinez Bridges is the Rio Vista Bridge across the Sacramento River (previously visited in May of 2010). This is the last bridge in our survey of Solano County bridges. It's a 2890 ft long vertical lift bridge that was built in 1944. It includes a 306 ft long Warren truss lift span across the river channel.

The Rio Vista Bridge is on State Route 12 (in the town of Rio Vista) and the bridge gets raised and lowered a lot, which can back up traffic for miles. The bridge tender was nice enough to let us into the bridge house so we could watch him raise and lower the lift span.

This bridge got an extensive seismic retrofit in the 1990s that included lead-rubber isolation bearings supporting the approach spans (see photo above) and viscous dampers that were placed transversely to allow the tower to rock if the anchor bolts were to break (see photo below).

Sacrificial expansion joints were used to accommodate large longitudinal movements. Also cable restrainers were placed in front of the counterweights to prevent them from swinging into the towers (see photo below). Thus, the retrofit allows movement and damage while preventing a collapse for the maximum credible earthquake. For a more moderate event, the retrofit may allow the structure to remain in service.

Solano County, California Bridges: Rio Vista Bridge across the Sacramento River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Solano County, California Bridges: Mare Island Causeway across the Napa River

January 2014 (38.11056 Degrees, -122.27472 Degrees) Mare Island Causeway

Just south of yesterday's State Route 37 Bridge is the lift bridge onto Mare Island (which is more like a peninsula) on the west side of the Napa River. People can get on and off the island using these two bridges. In this photo I'm standing atop the west tower of the new Carquinez Suspension Bridge looking up the Napa River, which empties into the Carquinez Straits.

The Mare Island Causeway was built in 1934. The bridge is 2008 ft long with a 165 ft long main span. It has long concrete trestle approach spans and a steel lift main span.  It's only 30 ft wide.

The lift span is normally in the closed position. It has 20 ft of vertical clearance on the deck and over 100 ft of vertical clearance across the channel when the lift span is opened.

Mare Island seems to be going through an economic depression. For over 100 years, it was the main Naval shipyard for the United States. In 1995 it was finally closed during the big round of base closures. Now there are many empty factories with broken windows. However, many entrepreneurs have bought the old factories for new ventures. For instance, Victor Zayas has a factory that builds friction pendulum bearings on the island.

Solano County, California Bridges: Mare Island Causeway across the Napa River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.