UP 6th Street Bridge (Racine)

Located in Racine, this through plate girder and steel stringer bridge carries the former Chicago & North Western Railway mainline over 6th Street. It is unknown what previous bridges were at this location. It is believed that an iron girder and stone structure was constructed during a double tracking project in approximately 1892. In the early 20th Century, the C&NW invested significant capital into this line, replacing light iron bridges with new heavier steel bridges. In 1908, a major project revised the line through Racine, constructing a new bridge across the Root River and replacing bridges across 6th Street and 9th Street. Currently, the bridge consists of a 47-foot through plate girder span, approached by a 9-foot steel stringer span on the south end and a 7-foot steel stringer span on the north end. The bridge is set onto stone abutments and steel bent piers. Stone for the abutments consists of a white limestone, likely quarried at Duck Creek, Wisconsin. The superstructure uses an unusual design, where the through plate girder span is effectively cantilevered and supported by additional longitudinal plate girders underneath the approaches. The through plate girder span uses a trough floor, with numerous parallel troughs between the girders. This span uses rounded and tapered girder ends, typical for through plate girders constructed for the C&NW. The approach spans are set directly onto a concrete deck, which is placed upon the additional plate girders. In addition, the entire bridge is set at a slight skew. Trough floors use transverse channels, which are filled with asphalt cement and ballast. This style of floor became popular in the early 20th Century, particularly for grade separations, as it reduced noise and limited the possibility of falling debris. The substructures use a standard design, with the abutments using stepped wing walls which extend perpendicular to the track. The piers are constructed of three steel columns, connected an X-bracing. While many piers of this design use a transverse plate girder, the transverse plate girders are set further back under the additional longitudinal girder, and are offset to account for the skew. The columns are set onto concrete footings. American Bridge Company fabricated the superstructure and steel bents, while an unknown contractor constructed the substructure. Trough floor girder and stringer spans were popular in the early 20th Century, as they were durable, easy to construct and met requirements for grade separations. Since the initial construction, the bridge has seen few alterations. While the bridge was constructed for two tracks, only the eastern track remains in service today. Overall, the bridge appears to be in fair condition, with no significant deterioration noted. The author has ranked this bridge as being locally significant, due to the common design.