Hospital Bridge — Downieville, CA - U.S. National Register of Historic Places on Waymarking.com

The following information from California State Parks Office of Historic Preservation files:

The Hospital Bridge, also known as the Downieville Steel Bridge, built in 1908 across the Downie River near its confluence with Pauley Creek, is rare surviving example of a steel pin-connected truss bridge that was once common throughout California. 100 feet long and 12 feet wide with timber stringers and decking, this bridge is a simple but striking example of Pratt truss bridge design, exhibiting a very high degree of historic integrity.

The Hospital Bridge is a 100 foot long through Pratt truss bridge spanning the Downie River east-west between Upper Main Street and Lavazzola Road. The bridge is constructed of riveted steel box members connected with lacing bars. The lower chords and stringers are steel I-beams. The top chords are C-channel members held together with lacing bars and topped by flat sheet steel. The end posts are C-channel members held together with lacing bars and topped by flat sheet steel. Verticals are C-channel held together with lacing bars, except for the outermost verticals, which have a base of C- channel members held together with lacing bars, topped by two steel rods attached with pins to the C-channels and the connection between the end posts and top chords. Struts are L-shaped structural steel. Top and bottom lateral bracing is flat structural steel, and each diagonal consists of two flat structural steel bars. The center two trusses have cross-diagonal members of steel rods connected via turnbuckles. Additional steel rods and steel bars are connected horizontally parallel to the lower chord, via large bolts at the base of each vertical, providing a common connection point for verticals and diagonals, mounted atop each floor beam by a U-shaped bolt and sections of C-channel. The roadway deck is wooden, with a lower layer of beams tangent to the road surface and two rows of four wooden beams parallel with the road surface. Guardrails consisting of two steel L-girders attached with interlaced lacing bars are located on either side of the bridge roadway, with chain-link fence affixed in front of the guardrails on either side of the roadway. The bridge is supported by board-formed concrete abutments on either side. The remains of earlier bridge abutments, consisting of irregular stone secured in place with concrete mortar, is visible behind the bridge abutments along the canyon wall. A water pipe runs along the southern side of the bridge, attached to the floor beams.

The Hospital Bridge today carries only pedestrian traffic but was once the only access to the historic settlements and mining country upstream from the gold rush community of Downieville. In the wake of the 1937 flood (see Section 8) it was the only intact bridge in the community until repairs could be made. The bridge was removed from service for vehicular traffic in 1980 with the construction of a nearby concrete structure designed to handle the traffic of loaded logging trucks.

The 1937 Downieville Flood

In 1937, Downieville had a total of five bridges. The easternmost (and farthest upstream on the Downie River) was the Hospital Bridge, originally called the Downieville Steel Bridge (due to its status as the town’s first steel truss bridge) constructed in 1908. Next was the Hansen Bridge, a Pratt pony truss bridge completed in 1936. Third was a concrete arch bridge constructed by the State of California to carry traffic on Highway 49. Just downstream of the highway bridge was the Jersey Bridge, a wooden bridge constructed in 1875, and the Durgan Bridge, just downstream of where the Downie River met the Yuba, constructed in 1881. Aside from the highway bridge, all were constructed as single-lane bridges by the county government.

On December 10, 1937, major storms sent a torrent of water through Downieville via both rivers. Nearly ten years had passed since the last high water, and an enormous amount of debris was swept into the river by the storm. State highway crews, aware of the storm’s danger, stood by to clear debris from the bridges, but as the river rose to the point where the highway bridge’s arches were underwater, clearing debris became impossible. The storm passed mostly under the Hospital Bridge and damaged the footings of the Hansen Bridge. The Highway 49 concrete arch bridge, unlike the truss bridges, had several pillars that extended into the river, and once road crews could no longer reach the bridge, debris collected on the piers and blocked the passage of water through the arches. The temporary dam brought the water level high enough to send the river through the streets of Downieville, lifting homes from their foundations and sending them floating downstream. The highway bridge could not withstand the pressure of the water and debris for long, and collapsed after approximately 30 minutes. The catastrophic break-through of water and debris caused more damage to the buildings of Downieville, and utterly destroyed the two wooden bridges downstream from the highway bridge, the Jersey and Durgan Bridges.

When Sierra County officials selected designs to replace the Jersey and Durgan Bridge in 1938, county engineer George Taylor designed two steel truss bridges. Taylor also chose to repair the damaged Hansen Bridge and retain the Hospital Bridge, whose unfashionable steel trusses had survived the disastrous 1937 flood. By the end of 1938, the town of Downieville was again connected by its four traditional single-lane bridges, all of steel truss design. The California Division of Highways rerouted Highway 49 temporarily over the Jersey Bridge as a temporary expedient until a new highway bridge could be constructed to replace the fallen 1936 bridge. As of 2016, no replacement bridge has been constructed, and the temporary expedient of the Jersey Bridge still carries Highway 49 through the city.