NS Sunset Avenue Bridge (Decatur)

View an article discussing the reconstruction of this line

Located on the south side of Decatur, this unique through plate girder bridge carries the former Wabash Railroad over Sunset Avenue (formerly St. Louis Avenue). A timber trestle bridge was first constructed here in 1881. In 1914, the Wabash would construct a 45-foot through plate girder span across St. Louis Avenue, set onto concrete substructures. Throughout the 1920s, the Wabash began to study improvements to this line, including constructing underpasses and reconstructing the St. Louis Bridge. In May 1926, contracts were awarded for the reconstruction of the St. Louis Bridge, rebuilding the underpass at St. Louis Avenue and constructing two new underpasses at Forest Avenue and Decatur Avenue. Work on the project was began later that year, and substantially completed in 1927. As part of the work, a large embankment was constructed, and the project exceeded a cost of $850,000.

Because the abutments from the previous bridge were too narrow, it was impossible to raise the bridge while keeping the abutments at the same location. As a result, it was decided to construct piers on the old abutments, and add concrete slab spans on either end. To improve the visual appearance of the structure, a concrete curtain wall would be constructed along the approaches, appearing as a solid abutment. Currently, the bridge consists of a 45-foot through plate girder span, approached by two 40-foot concrete slab spans on either end. The entire bridge is set onto concrete substructures, and the main span runs at a slight skew. The girder span uses a standard Wabash design, including a ballast floor consisting of parallel I-beams covered by a timber deck and square girder ends. American Bridge Company fabricated the girder span, while an unknown contractor constructed the original concrete abutments. The new approaches and substructures were constructed by the Carmichael-Cryder Company, which had the contract for concrete work on the entire project.

Through plate girder spans were popular for railroad use, as they were durable and easy to construct. The Wabash preferred solid floor spans, as it reduced the amount of maintenance required. The process of raising the bridge and constructing new approaches was an ingenious solution to a complicated problem. During construction, traffic over the bridge needed to be maintained. A temporary trestle was constructed on the west side of the bridge, which allowed uninterrupted work on the rebuilding of the bridge. Since the 1927 reconstruction, the bridge has seen little changes. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The author has ranked this bridge as being locally significant, due to the common design.