Photo taken Summer 1995 by Joe Elliott for the Historic American Engineering Record
BH Photo #101696
"Then, as now, the bridge consisted of a three-span cantilevered through truss of approximately 1,127', comprised of two cantilevered units of about 415' and one suspended span of about 297'. Each cantilevered unit consists of an anchor arm of about 237' with a cantilever of about 178'. The two cantilevers and the susepended span provide a channel crossing of about 653'. The cantilevered units are carried by concrete piers supported by foundation piles. The bridge was originally about 25' wide with an apprioximately 22' roadway. The original bridge floor was of sheet asphalt plank on treated timber plank supported by steel beams. Acording to the Prospectus issued in 1931 to obtain financing, the bridge was designed to accomodate 2,300 vehicles per hour with a maximum vehicle load of 30 tons. Pictures provided by The Book of the Black Hawk Bridge, a promotional document produced for the dedications ceremony in 1931, indicate that the entire bridge project, from Second Street, Lansing to the Burlington railroad tracks at the foot of the Winneshiek Slough and several smaller bridges over the Henderson, Stevens, Indian and Big sloughs. The road bed between the main span and the Wisconsin bluffs was paved with crushed stone. There were no approach spans on the Iowa side of the river. There was a toll booth at the Iowa end of the bridge, located immediately adjacent to the southwest end.
"Although the Black Hawk Bridge does not serve any primary routes, it provides a regionally important vehicular crossing of the Mississippi River midway between La Crosse, Wisconsin and Prairie du Chien, Wisconsin. According to bridge consultant Clayton Fraser, it is only one of five long-span cantliever truss bridges remaining in Iowa." "A reality! Finished!" The Book of the Black Hawk Bridge, enthused at the structure's dedication in 1931. "The Black Hawk Bridge, three quarters of a million dollars of steel and concrete, linking the states of Iowa and Wisconsin, running eastward from Lansing across the Winneshiek Bottoms to De Soto, is a reality. It is the first passenger bridge to join these two states, the result of more than a generation of dreaming and scheming, planning and promoting--and two years of actual construction." Planning for the bridge had begun in 1898 by Lansing businessmen J.P. Conway and Tom Bakeman. The two promoted the proposed structure for years as a boon to the community, eventually forming the Interstate Bridge Company in 1914 to secure a Congressional charter for the bridge. The charter, secured in 1916, was turned over to the Iowa-Wisconsin Bridge Company in late 1929. Under the direction of Des Moines financier John Thompson, the latter firm sold bridge bonds to finance construction, hired Minneapolis engineer Melvin B. Stone to design the bridge, and contracted with the McClintic-Marshall Company of Chicago to fabricate and erect the trusses. The bridge was christened the Black Hawk Bridge to honor famous Indian Chief Black Hawk. The bridge was dedicated on June 17, 1929, with the governors of Iowa, Wisconsin and Minnesota present. Thebridge functioned as a toll structure until flooding washed out some of the approach spans over the Wisconsin bottoms in 1945. It stood unused for several years until the approaches were re-constructed and the bridge re-dedicated in May 1957. The Black Hawk Bridge now carries traffic as a free bridge, in essentially unaltered condition. The importance of the Black Hawk Bridge to commerce and transportation in northeastern Iowa can hardly be understated. The only highway bridge over the Mississippi River in the region at the time of its completion, the Black Hawk Bridge is historically significant for its role in the development of northeast Iowa. Although its design and dimensions fit within the mainstream of bridge technology of the time, the structure is technologically significant as an uncommon, large-scale example of cantilevered truss design. Few such cantilevered trusses were erected in Iowa, those primarily over the Mississippi or Missouri Rivers, and even fewer remain in use today. The Black Hawk Bridge is one of only five such long-span, cantilevered trusses in Iowa. [adapted from Fraser and McWilliams 1992]