Year constructed: 1935-1936
Bridge type: Rigid-Connected Cantilevered Warren Deck Truss
National Register of Historic Places status:
Listed
Length: 2120 feet
Width: 43 feet
Spans: 5
FHWA: 009386
Jurisdiction: City of Ottumwa
Location: Jefferson Street over the Des Moines River in Ottumwa, Section 24, T72N-R14W (Center Township)
Details
Although it was built in 1935-36, the Jefferson Street Viaduct traces its roots 15 years earlier. Beginning in 1921 Ottumwa city officials began meeting with the CB&Q, the CRI&P and the CM&StP railroads with the idea of building a viaduct over the numerous tracks that paralleled the Des Moines River. Nothing concrete came of these discussions, however, and after a change of city administration, the project was shelved until 1929. Planning began again that year, with the city considering sites at several streets. Because the proposed bridge was to carry U.S. Highways 34 and 63, the city sought financial and design help from the Iowa State Highway Commission. ISHC agreed to fund construction of a new bridge over the Des Moines River, provided the city would pay for construction of the viaduct on the northern end. Between 1930 and 1935 ISHC presided over meetings with the city and the railroads in an effort to resolve differences among the three entities. Finally, highway commission engineers drew up a five-span, riveted Warren deck truss, cantilevered from massive concrete piers in the river. The highway commission designated the viaduct's construction Project P-480 and in December 1934 awarded a contract for it to the Wisconsin Bridge and Iron Company. The Milwaukee-based firm began excavations for the substructure early in 1935 and the bridge was completed in May 1936. At the dedication ceremonies on May 28th, Iowa Governor Clyde Herring and Ottumwa Mayor Edwin Manning spoke before a crowd of about 15,000 people, before two Ottumwa girls christened the bridge with bottles of champagne. The Jefferson Street Viaduct has carried heavy traffic since, with a major rehabilitation in 1983 as its most substantial alteration.
Fueled with federal funds from the various relief agencies, the Iowa State Highway Commission designed several large-scale urban viaducts in the 1930s. These featured a variety of superstructure types, but perhaps none was as distinctive as the Jefferson Street Viaduct in Ottumwa. The city had wanted a concrete bridge here, in part because of the aesthetics of the concrete arch form. But ISHC opted instead for this steel truss design as a more economical alternative. With its five arched deck truss spans held above the Des Moines River on tapered concrete pedestals, the structure is one of Iowa's most handsomely proportioned highway trusses. It is technologically noteworthy as an uncommon application of deck truss technology in Iowa, a state not known for generous underdeck clearances at its stream and river crossings. With its structural integrity largely intact, the Jefferson Street Viaduct was an important exercise in Iowa urban bridge construction in the 1930s [adapted from Fraser 1993].