Mississippi River Bridge
Rigid-Connected, Double-Deck Swing Truss
National Register of Historic Places
Iowa 2/Illinois 9 over the Mississippi River in Fort Madison
The first Santa Fe railway and roadway bridge to span the Mississippi River at Fort Madison was both a financial and transportation boon to the city. Wisely offering the Santa Fe Railroad incentives in the form of a bridge charter, tax reductions, and land for the railroads' switchyards and shops, Fort Madison secured the newest Mississippi River crossing in 1887. The Chicago Santa Fe, and California Railway contracted with Sooysmith & Son of New York to construct the bridge's substructure and with the New York-based Union Bridge Company to fabricate and erect the superstructure. Work on the structure's timber pile bents and masonry piers began in April 1887, and eight months later the 1,925-foot bridge was complete. Designed by Octave Chanute, the iron and steel bridge consisted of an eight-span single track through truss bridge, with wagon lanes cantilevered on brackets outside the trusses. The Fort Madison-to-Chicago bridge was subsequently replaced forty years later "having long been a (traffic) bottleneck" and also because it could no longer sustain the increasingly heavy traffic loads.
The first bridge's successor, the massive Mississippi River Bridge, a rigid-connected swing through truss, dates to 1925. Structural work on the bridge began in April 1925 by the Union Bridge and Construction Company of New York. The American Bridge Company, also of New York, was contracted to fabricate and erect the superstructure, based on plans delineated by A.F. Robinson of the Santa Fe Railroad. The structure consists of a riveted double-track, double-deck swing through truss, a nine-span deck girder on the east approach, and a ten-span deck girder on the west approach, in addition to four 270-foot Baltimore through trusses, and a 530-foot swing span. The bridge was built with 29 million pounds of metal and 46,000 cubic yards of concrete at a total cost of $5.5 million. Simply painting the behemoth cost over $100,000. Formally opened to traffic on 28 July 1927, more than four hundred men were employed throughout the bridge's construction.
The Mississippi River Bridge is notable not only for its overall length of 1,675 feet, but because its 525-foot electrified swing span was the longest and heaviest in the country at the time it was built. The swing span is used to allow river traffic to pass through the bridge, the process of which fascinates on-lookers from the river bank. Excluding damage incurred by river traffic and regular maintenance-related repairs, the Mississippi River Bridge has functioned as a toll bridge in essentially unaltered condition [adapted from Crow-Dolby and Fraser 1992].