Year constructed: 1889
Bridge type: Pin-Connected Pratt Pony Truss
National Register of Historic Places status: Listed
Length: 117 feet
Width: 15.7 feet
Spans: 1
FHWA: 104650
Jurisdiction: Cedar County
Location: Plum Street over Mill Creek, 1 mile north of Clarence, Section 15, T82N-R2W (Dayton Township)
Details
In June 1888 the Cedar County Board of Supervisors received a petition from citizens in Dayton Township for a new bridge over Mill Creek near the township center. The structure would carry wagon traffic on the road that extended northward from the small town of Clarence, in the north part of the county. Supervisor William Hahn viewed the proposed site and recommended that the county erect a single 66-foot iron span on pile bents. What the county built instead was a 58-foot pony truss on concrete-filled iron cylinder piers, with timber stringer approach spans. The board contracted for the bridges construction with Ward and Keepers, who held Cedar Countys annual contract for bridge construction and repair in 1888 and 1889. The Clinton-based bridge builders completed the medium-span truss in 1889. The bridge displayed typical pin-connected design and detailing for its early date; two distinguishing features are the tapered "fishtail" riveted girder floor beams and the inclined lower chords at the outer panels. Over its hundred years of use, the Mill Creek Bridge has undergone several sub-structural alterations, including construction of concrete abutments on the south, encasement of the base of the northeast cylinder with concrete, and construction of new timber pile piers beneath the approach spans. The bridge no linger carries traffic and stands abandoned, with its superstructure intact but the deck in deteriorating condition.
Completed in January 1877, the Cedar Bluff Bridge over the Cedar River was the first all-iron span in Cedar County. It was followed by four other modest iron spans later that year. By the time the supervisors undertook the Mill Creek Bridge in 1888, Cedar County had contracted for several other iron spans, including major structures over the Cedar River at Rochester and Cedar Valley. This medium-span pony truss was thus neither the earliest nor the largest all-metal wagon bridge erected by the county. However, it is today distinguished as the last remaining bridge from this formative construction period. The structure is technologically representative for its period of construction. Comprised of a wrought iron, pinned Pratt pony truss, the bridge exemplified wagon bridge construction in Iowa in the late 19th century. One of the states oldest pony trusses, the Mill Creek Bridge is an important remnant of early Iowa transportation [adapted from Fraser 1990].