CPKC Kinnickinnic Avenue Bridge (South)

Located on the south side of Milwaukee, this through plate girder bridge carries the former Chicago, Milwaukee, St. Paul & Pacific Railroad (Milwaukee Road) Bay View line over Kinnickinnic Avenue (Wisconsin Highway 32). In the early 20th Century, the City of Milwaukee ordered grade separations at many of the busy railroad lines throughout the City. Inspired by track elevation projects in Chicago, early ordinances were passed for both track elevation and depression in approximately 1904, and the ordinances later expanded to include several other lines throughout the City. In approximately 1908, an ordinance was passed requiring the elevation of the Milwaukee Road mainline from downtown Milwaukee to a point south of the Kinnickinnic River. The first portion of this elevation came between 1909 and 1910, when the mainline line was elevated between south of Lincoln Avenue and north of Kinnickinnic Avenue. As part of the work, the Bay View Line, which branches off the mainline near Beecher Street, was also elevated to cross Kinnickinnic Avenue. In 1910, the present structure over Kinnickinnic Avenue was completed.

Currently, the bridge consists of a 45-foot through plate girder span, approached by an 11-foot through plate girder span on either end. The bridge is set onto concrete abutments and steel bent piers. In addition, a lengthy curved timber pile trestle approach is located on the east end of the bridge, as it was likely the cheapest way to return the railroad to ground level. It is also possible that it was unclear to the Milwaukee Road if further elevations would be required along this line, so this provided an initially temporary solution to reach ground level. The main span uses a typical design for track elevation projects, with two modest sized girders, which are constructed with rounded girder ends. The approach spans utilize shallow girders and square girder ends. All three spans use a floor constructed of a grid of I-beams, encased in concrete. The piers are constructed of two V-laced columns, set onto concrete pedestals and connected by a lattice beam on the top. While the west abutment uses a standard design with sloped wing walls, the east pier uses a square design, possibly further evidence that a retaining wall was eventually planned. An unknown contractor fabricated the superstructure, while it is believed that all concrete work was completed by labor employed by the Milwaukee Road Bridge & Building Department. Through plate girder spans were popular for grade separations, as they were durable and easy to construct. In addition, solid floors were easy to add to these spans, to provide greater protection to vehicles and pedestrians beneath. Since the initial construction, the bridge has seen no significant alterations, and remains in occasional use. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The pedestals at the base of the piers were encased with concrete in approximately 2010, repairing a deteriorated component of the bridge. The author has ranked this bridge as being locally significant, due to the common design.