Year constructed: 1918
Alternate name: Volga River Bridge
Bridge type: Concrete Open Spandrel Arch
National Register of Historic Places status:
Listed
Length: 156 feet
Width: 17.1 feet
Spans: 1
FHWA: 119020
Jurisdiction: Clayton County
Location: Evergreen Road over the Volga River, northeast side of Mederville, Section 22, T92N-R5W (Cox township)
Details
This concrete arch bridge crosses the Volga River just outside of Mederville, in Cox Creek Township. Featuring two tapered arch ribs that spring dramatically from concrete pedestals, the bridge spans 155 feet over the deep ravine on the northern edge of the small town. The Mederville Bridge was built as a replacement for an earlier structure at this crossing, a 155-foot, covered timber Howe truss. Designed by Des Moines civil engineer James B. Marsh, its construction was first let for competitive bids in February 1918. When proposals were received in March, the county rejected all as too high. The supervisors re-solicited for bids and in June received proposals from six firms: the Des Moines Bridge and Iron Company, Alfred Olson, Rodies and Bales, the Federal Bridge Company, C.H. Williamson, and F.E. Marsh and Company. After considering the proposals, the supervisors contracted with F.E. Marsh to build the crossing for $17,454.32, including engineering fees. Presumably completed later that year, the Mederville Bridge has functioned in place since, in unaltered condition.
With the Iowa State Highway Commission and influential Iowa bridge contractors James Marsh and N.M. Stark actively promoting the concrete arch as an economical alternative to the steel truss for wagon bridge construction, Iowa's counties built hundreds of small-scale arches in the 1910s. Few of these structures even approached the 155-foot span necessary for the Mederville crossing, however. For this steep-sided location, James Marsh delineated an open spandrel concrete arch, which was bid competitively with the steel truss designed by the highway commission. By using an open spandrel arch, he could achieve a relatively long span at a reasonable cost, while contributing aesthetically to the small town setting in which the bridge stood. Relatively few open spandrel arches were ever built in Iowa. The Mederville Bridge is noteworthy as one of the earliest open spandrel arches built in the state. As it arches gracefully over this wooded valley, the Mederville Bridge is a handsomely proportioned example of this rather uncommon concrete technology [adapted from Crow-Dolby 1992].