Centennial Bridge

Information and Findings From Iowa's Historic Bridge Inventory

Discussion of Bridge

Of the myriad bridges crossing the wide murky Mississippi river, the Centennial Bridge, connecting Davenport, Iowa, and Rock Island, Illinois, claims the distinction of being the first tie-arch form bridge across the Mississippi River. Furthermore, the project's design, construction, and financial backing define its significance on several distinct levels. Approval by the commission of the bridge design drawn up by the Kansas City engineering firm of Howard, Needles, Tammen, and Bergendoff was finalized in late winter of 1939. In April the commission let the foundation contract to McCarthy Improvement Company of Davenport, Iowa. Construction began the same month and McCarthy was fortunate to discover, during the pier-building process, that individual piers could be founded on solid bedrock, either limestone or blue shale rock. Progressing rapidly, American finished its work early in 1940 and the bridge officially opened for traffic on 21 July 1940. Since its construction, the Centennial Bridge's only major alteration of note is that it currently operates as a free crossing instead of a toll bridge. Barring this planned conversion, the Mississippi River bridge carries heavy traffic while retaining an exceptionally high degree of structural and historical integrity. One of the primary designers working for Howard, Needles, Tammen, and Bergendoff of Kansas City, Edward Ashton of Iowa City, was responsible of many of Centennial Bridge's unique attributes. This structure combined Ashton's inherent thriftiness with his vision of simplistic beauty. The clean lines and lack of ornamentation of the tied arch configuration proved to be both cost efficient and visually striking. As far as aesthetics was concerned, Ashton particularly admired the view of the trusses as one approached the main spans. The simple massiveness of the structure makes a strong statement about how Ashton felt bridges should appear. The Centennial Bridge is a significant Iowa highway-related resource for several reasons. The structure is historically important as in important crossing of a major Midwestern river. The Centennial Bridge is technologically significant as the first tied-arch span across the Mississippi River--a nationally important example of this inherently long-span design. And, considered by Ashton to be the best bridge he had ever designed, this gracefully proportioned structure is significant for its association with one of Iowa's most influential engineers [adapted from Crow-Dolby 1992].

Bridge Considered Historic By Survey: Yes