BNSF W. Branch Floyd River Bridge

Once located along Iowa Highway 10 between Sioux Center and Maurice, this unusual through plate girder bridge carried a former Great Northern Railway mainline over the West Branch Floyd River. The first bridge at this line consisted of a lengthy timber pile trestle bridge, constructed when the line was first built and periodically upgraded. In 1944, the bridge was upgraded by installing three secondhand through plate girder spans across the main channel and overflow channel. The bridge consisted of seven timber pile trestle spans, a 60-foot through plate girder span over the main channel (north span), 38 timber pile trestle spans, two 40-foot through plate girder spans (center and south spans) and eleven additional timber pile trestle spans. The entire bridge was set onto timber pile substructures. The three through plate girder spans used slightly different designs, and were likely relocated from three different unknown locations. All three spans appear to have originally been fabricated in 1900 by an unknown contractor.

The northern through girder span used two heavy plate girders, which contained a diagonal brace across the two outer panels on each end. The floor of this span was simply constructed, with two stringers and standard floorbeams. The center span also used two heavy girders and a standard floor, but did not contain any diagonal bracing. The southern span used a similar design to the center span, but contained diagonal bracing across only the southern two panels. It is unclear if the diagonal bracing present on the northern and southern spans was originally part of the design, or if it was added at a later date to strengthen the span. Through plate girder spans were commonly used by railroads, as they were durable and easy to construct. Railroads often reused steel spans, as it provided a cost effective way to upgrade bridges without requiring large amounts of material. These three spans could have come from anywhere on the GN system, and there is no obvious possible spots that they were reused from. In 2020, work to replace the bridge began by replacing the southern approach with precast modular concrete girder spans on new steel pile piers. Work was halted through 2021, before the steel spans and north approach were replaced in 2022. The center section of the bridge was replaced in 2023, providing a completely new structure. At the time of documentation, the bridge appeared to be in fair condition, with deterioration to the timber components noted. The steel spans appeared to be well maintained with an intact coat of paint. The author has ranked this bridge as being locally significant, due to the common design and unknown history.