Rock Rapids Trail Bridge

Located in Rock Rapids, this attractive plate girder bridge carries the former Rock Island Sioux Falls Branch over the Rock River. At this location, the Rock River splits into two distinct channels, forming an island. The first bridge at this location consisted of a timber bridge, with the channel spans constructed of combination Howe through truss spans and the approaches and island spans consisting of timber pile trestle spans. In the late 1890s and early 1900s, the Rock Island made significant improvements to this line, replacing timber bridges with steel, stone and concrete structures. The original timber bridge was replaced in sections over a four year period, likely to minimize disruptions to railroad traffic. In 1898, a new stone west abutment, west pier (pier #9) and through girder span (span #10) were constructed across the west channel of the river. In the summer of 1899, a new east abutment and several stone piers (piers #1 and #3 through #8) were constructed in preparation for installing steel spans. Due to delays in production, the seven deck girder spans (span #1 and #4 through #9) were not installed until 1900. The final section to be replaced was across the east channel, where a concrete pier (pier #2) was constructed in 1902 and the two through plate girder spans (spans #2 and #3) were installed in early 1903, giving the bridge its present configuration.

Currently, the bridge consists of a 44-foot deck plate girder span (span #1), two 78-foot through plate girder spans (spans #2 and #3), six 44-foot deck plate girder spans (spans #4 through #9) and an 80-foot through plate girder span (span #10). The superstructure is supported on stone substructures, with the exception of pier #2, which is constructed of concrete. Unique to this bridge, the structure is set on a 3.7-degree curve. All three through girder spans are similar, consisting of heavy plate girders, a standard floor and rounded girder ends. The deck plate girder spans also follow a standard design, and consist of two modest sized girders. The substructures also follow a standard design, with rectangular piers and abutments with stepped wing walls. Stone for the substructures was likely quarried at the Cedar Valley, Iowa quarry; which supplied all stone for the BCR&N. American Bridge Company fabricated spans #2 and #3, while unknown contractor(s) fabricated the remaining spans. Pier #2 was constructed by railroad company forces, while it is unclear if the remaining substructures were constructed by company forces or under contract. Girder spans were commonly used by railroads, as they were durable and easy to construct. Since 1902, the bridge has seen no significant alterations. Today, the bridge is used as part of a trail and is listed on the National Register of Historic Places, along with the depot at the west end of the bridge. A wooden deck and handrails have been added to the bridge. 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.