Historic Bridges of Iowa
||pinned Whipple through truss|
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Abandoned part of Three Bridges Road over the Iowa River, 5.4 miles east of Marshalltown, Section 3, T83N-R17W (Green Castle Township)
The bridge over the Iowa River near the town of Quarry in Le Grand Township was one of Marshall County's oldest spans when it collapsed during late spring flooding in 1885. In June the board of supervisors hired the Wright Brothers, local contractors, to pull the wrecked structure from the river, and subsequently solicited competitive proposals from bridge companies for a replacement span. On July 1st the board awarded a construction contract to low-bidder King and Twiss of Des Moines for a 150-foot Whipple truss identical to the Stanley Mill Bridge, built by the county the year before. Using a superstructure fabricated by the King Iron Bridge Company of Cleveland, Ohio, the builders completed the bridge by September at a total cost of $3,295. The Quarry Bridge has carried traffic since, with the reconstruction of its north abutment with concrete the only major alteration of note.
As Marshall County's oldest originally placed wagon bridge, the Quarry Bridge is historically significant as an early wagon crossing. The structure is further distinguished as a well-preserved example of the Whipple through truss. Basically a Pratt with diagonals that extend over two panels, the Whipple truss was seldom employed for wagon trusses in the state. Few were ever erected and fewer yet remain today. For its exceedingly rare use of wrought and cast iron components, its rare truss configuration, and its long-standing role in regional transportation, the Quarry Bridge is a significant early transportation-related resource [adapted from Fraser 1989].