1887 Iron Bridge at Manitowoc Rapids Is a Significant Engineering Achievement

In 1887, a single span Pratt truss bridge over the Manitowoc River on the Green Bay Road, south of the village of Manitowoc Rapids, was built by the Wisconsin Bridge & Iron Co. of Milwaukee. The firm, founded by Friedrich and Reinhold Weinhagen in 1886, became one of the states’s leading bridge manufacturers.

The Green Bay Road bridge, 150 feet long × 15 feet wide with a truss height of 23 feet, is set on massive cut stone abutments. The six-panel bridge features vertical and angled end posts, light tension diagonals which slope toward the center of the bridge and a flat top chord – common design elements of a Pratt overhead truss patented in 1844 by American engineers Thomas and Caleb Pratt for highway and railroad bridges.

Particularly interesting are the triangular, sunburst builders’ plaques mounted atop portal struts at each end.

The Green Bay Road iron bridge replaced an earlier wooden structure built by Ira Clark and Thomas Cunningham in 1847, one year before Wisconsin statehood. This was the first bridge built in Manitowoc County. Prior to a bridge crossing, travelers had to ford the river at The Rapids.

In May 1887, due to safety concerns, the Manitowoc Rapids Town Board petitioned the Manitowoc County Board of Supervisors for one-half of the $4,075 cost of constructing a new bridge, as stipulated under state bridge laws. On June 2, the petition was adopted on a vote of 17 to 8.

The Green Bay Road bridge was virtually identical to a double-span Pratt truss bridge, 302 feet long, built to replace a wooden structure at Rapids in 1886 by Friedrich Weinhagen when he was agent for the Pennsylvania Bridge Works. This iron bridge was located about three-quarter mile downstream of the Green Bay Road crossing, just beyond a horseshoe bend in the river. The Broadway Street bridge, costing $6,600, was replaced by concrete spans in 1986.

The Green Bay Road was one of the earliest overland routes in Wisconsin. Built in the 1830s as a military road between Fort Howard at Green Bay and Fort Dearborn at Chicago, it also served as an early mail route. The road was an important route for immigrants and settlers coming to the area.

For nearly 70 years, the Green Bay Road (old Highway 119) at Manitowoc Rapids was one of the primary routes to Manitowoc until 1956 when County Trunk Highway R (Rapids Road) and a two-lane concrete bridge were constructed to bypass this portion of the historic roadway and river crossing. In 2019, the Rapids Road bridge was replaced by a four-lane span. This new concrete bridge is visible from the old iron bridge, a short distance downstream to the east.

The Green Bay Road bridge remained open to one-lane traffic on this section of the former highway, renamed Mill Street for the old Klingholz grist mill located  nearby on the south bank of the Manitowoc River. In 1962, the 3-inch wood plank deck was replaced at a cost of $5,333.19.

After 136 years, the Green Bay Road bridge remains today on the landscape in the southeast quarter of Section 23, Township 19 North, Range 23 East, just behind the Shipbuilders Credit Union branch office at Rapids. The bridge, closed to vehicular traffic since the late 1990s, has been converted for bicycle/pedestrian use. Black and yellow 9' –6" clearance signs to discourage truck traffic remain from when the bridge was still in use. With the exception of deck repairs and rust, the iron bridge remains remarkably intact and well-preserved.

The Green Bay Road bridge was listed on the National Register of Historic Places in 1998. It is of statewide significance in engineering as one of the oldest remaining Pratt truss bridges from the pre-1890 period still on its original site in Wisconsin.