© Iowa Department of Transportation
BH Photo #314775
Among the Madison County bridges included in Iowa's historic bridge inventory is this five-panel, pin-connected Pratt pony truss. The structure crosses an unnamed stream along a secondary road seven miles northwest of Winterset in Union Township. Named the Miller Bridge after an adjacent landowner, the structure features early Pratt truss characteristics, including, tee-iron verticals, unslotted turnbuckles and channel floor beams. The substructure is comprised of concrete-filled iron cylinder piers with timber and concrete abutments. The Miller Bridge dates to 1884. In the spring of that year the Madison County Board of Supervisors received a petition for a permanent structure at this crossing. The county contracted with local contractor V.S. Callison to provide and erect an 80-foot iron bridge. But when Callison had failed to begin construction by July, the supervisors released him from the contract and solicited competitive bids for an 82-foot iron truss. Proposals were received from the Milwaukee Bridge Company, Raymond and Campbell, the Smith Bridge Company and King and Twiss of Des Moines. Low bidder at $764.56, King and Twiss received the contract to supply the truss. The county then hired local contractors H.P. Jones and G.K. Foster to build the iron tube substructure (also supplied by King) and erect the truss. Completed later that year, the Miller Bridge has functioned in place since, with only maintenance-related repairs. From the 1880s through the 1910s, thousands of pinned Pratt pony trusses were erected on Iowa's roadways. Although several hundred of these structures remain in use today, less than fifty are known to predate the turn of the century. Fewer yet of the 19th century survivors remain structurally intact. The Miller Bridge stands out as one of Iowa's earliest documented Pratt pony trusses still intact [adapted from Fraser 1992].