110th Avenue Brush Creek Bridge

Located west of Lucas, this bridge carries 110th Avenue over Brush Creek alongside a former Chicago, Burlington & Quincy Railroad mainline. Typically, crossing agreements with railroads stipulated that the railroad was responsible for constructing and maintaining bridges on their right-of-way, including any necessary bridges to carry roadways over ditches or creeks. It is unclear if there was previously a bridge at this location. In 1935, the present bridge was installed. Currently, the bridge consists of a 42-foot, 6-panel, riveted double intersection Warren pony truss span, approached by a single timber pile trestle span on either end. The entire bridge is set onto timber pile substructures. The truss span was originally fabricated in approximately 1885 for use as a railroad bridge at an unknown location. It appears that the majority of the truss is likely constructed from wrought iron. Upon being installed here, the bridge was partially rebuilt with additional stringers, a wooden deck and was converted to roadway use. Unique to this bridge, it does not appear that the span was widened at all to carry roadway traffic. Detroit Bridge & Iron Works fabricated the truss span, while the remainder of the bridge was constructed by railroad company forces.

The truss span follows an unusual design for the CB&Q, but is similar to other spans constructed for other Midwest railroads. Both the top chord and endposts consist of heavily riveted T-shaped beams, which are composed of a solid plate with L-shaped bars added to either side. The bottom chord uses a similar design, although it contains more splice plates and less rivets. The vertical members use T-shaped bars, formed from two L-shaped bars joined together. Unique to this bridge, there is no vertical member dividing the center two panels. The diagonal members use a light design, and consist exclusively of L-shaped bars. The floorbeams are composed of light plate girders, while the main stringers use metal I-beams. Two additional timber stringers were added between the metal stringers and one additional timber stringer was added at the outsides of the metal stringers. Additional hangers were added to the floorbeams to support the timber stringers. The floor consists of standard creosoted timber planks, and thin wooden boards are used above the metal stringers to support the deck. The approaches use a standard design, consisting of standard timber stringer spans. All substructures are composed of single bents, and the abutments are backed with a standard timber backwall. While the bridge likely originally had a wooden railing, this railing appears to have been replaced by a standard steel plate guardrail in the early 21st Century. Double intersection Warren truss spans were commonly used by a handful of Midwest railroads in the 1880s, although this is the only known example used by the CB&Q. Notably, the truss span is particularly short for this design, and it is unclear if the span was shortened from its original length. The use of light members may indicate that the bridge dates to earlier in the 1880s.

Railroads often reused steel and iron spans, as it provided a cost effective way to construct bridges without requiring significant amounts of new materials. In particular, aging metal spans were commonly reused for roadway bridges, either with or without significant alterations. In the late 19th and early 20th Century, hundreds of overpasses and railroad-adjacent roadway bridges were constructed throughout the United States by reusing metal railroad bridge spans. As automobiles became larger and heavier in the 20th Century, these spans became outdated often had severe geometric deficiencies. Since the mid-20th Century, a vast majority of reused railroad spans in the United States have been removed or replaced. Often, the metal portions of these bridges were still serviceable, but poor geometry, limited records and deteriorated timber components required the complete replacement of the structure. Because these bridges were typically maintained by the railroad, records are not typically publicly available. As a result, the complete history of the bridge is often unclear, and historic determinations are made using absent or incomplete information. Since the initial construction, the bridge has seen no significant alterations. The bridge was closed to traffic in approximately 2010, and has remained abandoned since. Overall, the bridge appears to be in fair condition, with no significant deterioration noted. A vehicle strike damaged a portion of the western top chord, crushing the top of the beam. Unfortunately, this bridge will inevitably be removed in the future. It is hoped that the truss could be salvaged for use as a pedestrian bridge or light vehicular bridge, as it is likely among the oldest remaining truss bridges in Iowa. The author has ranked this bridge as being regionally significant, due to the unique design, age and unclear history of the structure.