Yale Bridge (also known as the Lewis River Bridge) is a short-span steel suspension bridge that spans the Lewis River near Yale, Washington, United States. It was built in 1932 by Cowlitz and Clark counties and was listed on the U.S. National Register of Historic Places on July 16, 1982.
Location and Specifications
The bridge carries State Route 503 across the Lewis River near the unincorporated community of Yale, Washington. It has a clear span of 300 feet (91 m) and a total length of 532 feet (162 m). The road deck, stiffened by a steel Warren truss, is situated 50 feet (15 m) above the high water line of Lake Merwin, a reservoir created by the construction of the Ariel Dam. The water depth at the site is approximately 90 feet (27 m), which necessitated a bridge design that did not require support piers in the water.
History
The bridge was designed by Harold H. Gilbert of the Washington State Highway Department and constructed by the Gilpin Construction Company of Portland, Oregon. It replaced a previous steel truss bridge at the same location. The counties transferred ownership of the bridge to the Washington State Department of Highways in the late 1930s. It underwent a major refit in 1957–58, during which the original timber approach spans were replaced with steel approach spans.
Structural Features
Yale Bridge is the only short-span steel suspension bridge in Washington State. It incorporates several unique engineering features:
- Only the central span is suspended from the cables. Separate, unloaded cables act as backstays, running from the 88.75-foot (27.05 m) tall towers to concrete anchorages embedded in the rocky canyon sides.
- Unlike most suspension bridges, where cables run continuously over saddles on the towers, the cables on Yale Bridge are discontinuous at the towers. This design allowed for smaller cables due to reduced wear.
- The bridge deck is constructed of timbers with an asphalt overlay.
Recognition
The bridge is noted for prominent brackets that support osprey nests on its towers. It was added to the National Register of Historic Places on July 16, 1982 (NRHP reference No. 82004206), and has been documented by the Historic American Engineering Record (HAER No. WA-87).
