Joliet Railroad Bridge

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Located in Joliet, this large through truss lift bridge carries the former Chicago, Rock Island & Pacific Railway over the Des Plaines River. The first bridge at this location was likely a wooden truss bridge, which was likely upgraded multiple times in the 19th Century. In 1900, the bridge was reconstructed with a five span double track deck plate girder bridge, set onto concrete substructures. The superstructure of this bridge was fabricated by the Chicago Bridge & Iron Company, and the substructures were likely constructed by company forces. In addition, a 153-foot quadrangular lattice through truss bridge carried the railroad over the Illinois & Michigan Canal at the west end of the Des Plaines River bridge. In the early 1930s, the Army Corps of Engineers sought to improve the Des Plaines and Illinois Rivers for navigation, creating the Illinois Waterway. As part of the improvements of the waterway, a number of fixed-span railroad bridges would be replaced or retrofitted with vertical lift spans.

Owing to the acute angle at which the railroad crosses the river, a large lift span would be required for the new bridge. Work began in 1931, and was completed in 1932. As part of the work, new piers would be constructed at either end of the lift span, and the existing abutments retrofitted for the new bridge. As part of the work, the tracks were raised 12 feet to accommodate the new elevation of the bridge. As part of the work, the old deck plate girder spans were raised span by span, while the truss at the west end had to be raised as a single unit. This work involved using temporary timber cribbing on top of the original substructures. After these spans were raised, erection on the new bridge could commence. Work continued through 1932, with minimal interruption to railroad traffic. At least one track was kept open at all times. After completion of the new bridge, the old bridge would be removed. It is unknown if the spans from the old bridge were reused elsewhere, which was common practice for the Rock Island. American Bridge Company fabricated the superstructure, towers and machinery; while the Herlihy Mid-Continent Company constructed the substructures. Erection work, including the temporary configuration of the old bridge, was handled by the Ketler-Elliot Construction Company. The new bridge, including the design and sequence of construction was performed under the direction of Chief Engineer William H. Peterson and Bridge Engineer Irvin L. Simmons. As part of the bridge reconstruction, the separate Illinois & Michigan Canal was removed, and would use the main channel of the Des Plaines River.

The bridge consists of a double track 306-foot, 20-panel, riveted subdivided polygonal Warren through truss vertical lift span. This span is approached by a 100-foot, 8-panel, riveted subdivided Warren through truss on the east end and a 151-foot, 12-panel span of the same design on the west end. All three spans are heavily constructed, using a combination of solid and heavily built-up members, a ballast deck and heavily constructed portal bracing. In addition, the lift span uses vertical endposts, which allowed for the construction of the large towers. The entire bridge is set onto concrete substructures, and the piers each consist of two columns constructed parallel to the river. The steel towers were constructed integrally with the lift span and approach spans, which required careful construction. These towers are connected to the superstructure by riveted connections, located at the hip vertical of the approach spans, and the end panel of the main span. The operating house is located on the south face of the west abutment.

The lift span is a tower driven span, consisting of massive towers, which carry a counterweight. This counterweight is operated by a set of wheels on each tower, typical of spans from this era. This bridge is an early example of a direct lift span, where the machinery is driven on the towers, and the counterweights are each carried by sixteen cables. This type of span was first used as part of a Rock Island bridge across the White River in Arkansas, and quickly became the standard for vertical lift spans. Previous lift spans used cables which were separate from the counterweights. The subdivided Warren through truss design became popular with the Rock Island in the late 1920s, as it allowed for an exceptionally strong span, while not sacrificing economy. Since the initial construction of the bridge, the structure has seen very few alterations. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. While the bridge was built for two tracks, only the northern track remains in use today. The author has ranked this bridge as being regionally significant, due to the lift span design.