St. Joseph Railroad Bridge

View an article discussing the 1917 reconstruction of this bridge

Located in St. Joseph, this large swing bridge once carried the Union Pacific subsidiary St. Joseph & Grand Island Railway across the Missouri River. The first bridge at this location opened in 1873, and was an iron truss swing bridge, fabricated by the Detroit Bridge & Iron Works. By 1904, this bridge had become too light for traffic, and would be replaced with a new bridge reusing the stone piers. The 1904 bridge utilized two 298-foot and one 295-foot 12-panel pin-connected Pennsylvania through trusses, with a 358-foot pin-connected swing span. The new spans would be fabricated by the American Bridge Company, which fabricated most spans for the Union Pacific in the early 1900s.

In 1915, severe deterioration to the pivot pier was discovered, and deterioration of the other piers was soon noted as well. The first plan was to construct new piers downstream of the existing bridge, and shift the spans laterally to the new piers. These plans were submitted to the War Department. The War Department deemed the swing span inadequate, and required the installation of a larger span. A new design was developed, which resulted in constructing new piers at an offset under the existing structure. The three Pennsylvania spans would be shifted 140 feet to the west, and a new swing span installed. The new swing span utilized a 465-foot, riveted subdivided Warren through truss, with each leaf utilizing 7 panels, for a total of 16 panels. In addition, an 80-foot and a 60-foot deck plate girder span were installed on the east end of the bridge. The substructures would be built of concrete, and were constructed by the Missouri Valley Bridge & Iron Company. American Bridge Company fabricated the new swing and deck girder spans, as well as shifting the existing spans to the new substructures. Work was completed by early 1918.

The Pennsylvania through truss design was commonly used by railroads starting in the early 20th Century. This design was well suited for long truss spans, often exceeding 300 feet. These spans utilize heavily laced members and X-frame portal bracing. The swing span utilizes a modified subdivided Warren design, with only the panels closest to the pivot pier utilizing subdivision members. The swing span is constructed with heavy members, riveted connections and a solid portal bracing. The deck girder spans are somewhat unusual, using widely spaced girders. It is unknown why this feature was added to the girders. Overall, the bridge appears to be in fair to good condition, with no significant deterioration noted. The bridge is now used by UP to access industries in Elwood, and is used a handful of times each week. The author has ranked this bridge as being highly significant, due to the unique design and history.