Year constructed: 1929
Alternate name: Spring Street Bridge
Bridge type: Concrete Open Spandrel Arch
National Register of Historic Places status:
Listed
Length: 142 feet
Width: 19.7 feet
Spans: 1
FHWA: 009970
Jurisdiction: City of Rock Falls
Location: Spring Street over the Shell Rock River in Rock Falls, Section 21/22, T97N-R19W (Rock Falls Township)
Details
Dating from 1929, this long-span concrete arch carries Spring Street across the Shell Rock River in Rock Falls, a small community northeast of Mason City. Plans for the bridge, prepared by the Iowa State Highway Commission, were first drafted in September 1928, with revisions made the following February. Competitive bids were solicited by the county that spring, and on April 29th a contract to build this bridge and five others was awarded to C.A. Holvik of Mason City. Holvik began work on the substructure soon thereafter, completing the bridge later in 1929. Since then the Rock Falls Bridge has carried traffic, in unaltered condition.
Although state highway commission engineers typically use riveted steel trusses for medium-span river crossings in rural settings, they used concrete open spandrel arches for a number of urban and small town structures in the 1920s. The Mederville Bridge, built in 1918, was apparently the first of these, designed as an alternate to a steel truss bridge. By using open spandrel arches, ISHC could achieve a relatively long span at a reasonable cost, while contributing aesthetically to the urban settings in which the bridges stood. But given the restrictive parameters of the arches' use--urban setting, long-span crossing, sufficient vertical clearance--only a few were built during this period. The Rock Falls Bridge is distinguished as a well-preserved example of this application of urban bridge design. The centerpiece for this small town, it is a local landmark and an important transportation-related resource [adapted from Hybben, Roise, and Fraser 1992].