Year constructed: 1890; 1902-1903
Bridge type: Pin-Connected Pratt Through Truss
National Register of Historic Places status:
Listed
Length: 345 feet
Width: 15.1 feet
Spans: 2
FHWA: 316660
Jurisdiction: Tama County
Location: 385th Street over the Iowa River, 4 miles southeast of Chelsea, Section 26, T82N-R13W
(Salt Creek Township)
Details
In April 1890 the Tama County Board of Supervisors received a petition from S. Wyman and other citizens of Salt Creek Township for a permanent bridge over the Iowa River southeast of Chelsea. The supervisors visited the proposed site, known locally as the Chambers Ford, the following month. They agreed to construct an iron bridge at this point if the citizens would "procure a right-of-way for said bridge and build all necessary trestle work on said right-of-way and all approaches to said bridge." The County Auditor subsequently solicited bids for the bridge's erection, and on July 11th a contract was let to the Clinton Bridge and Iron Works of Clinton, Iowa, for a single-span, pin-connected Pratt truss. Apparently completed later that year, the Chambers Ford Bridge functioned in place with only maintenance-related repairs for ten years. By the turn of the century, however, the original timber trestle approach that the local citizens had built on one end had deteriorated beyond the point of repair. In September 1902 the board of supervisors inspected the bridge and met with representatives of bridge firms at nearby Belle Plaine. A contract for the repair work, which included the erection of a new Lackawanna and Jones and Laughlin, King erected the new span during the fall and winter of 1902-03. Work was completed by April 1903, whereupon the county issued a warrant to King in the amount of $3,987. Since that time, the two-span structure has carried vehicular traffic in essentially unaltered condition. The south span is part of the original 1890 structure built by the Clinton Bridge and Iron Works, while to the north is the span built by the George E. King Bridge Company in 1903.
With virtually all of the in-state and national bridge companies promoting it, the pin-connected Pratt through truss was the steel bridge of choice for medium-scale crossings in Iowa in the late 19th century. Thousands of such spans were erected on the state's road system during this period of intense bridge construction activity, and today they remain the most populous structural type remaining from the 19th century. The Chambers Ford Bridge is distinguished among these for its staged construction, two-span configuration and well-preserved physical state [adapted from Fraser 1990].