Iowa Falls is a city that is known for its historic concrete arch bridges, with three open spandrel arch bridges in town all listed on the National Register of Historic Places, and indeed have been included as part of a historic tour. The bridge that serves the main road through town, US-65 (Oak Street) is the largest of the three and the most visually impressive. In addition, it is more significant than the other two bridges because it spans the entire river with a single span which is the longest span among the three bridges. The large span length and high-level design of the bridge makes it a significant engineering achievement. Indeed, this bridge when built was the largest single arch span of steel or concrete in the entire state of Iowa when completed. The bridge's design is both elegant and graceful, with its sweeping arch that integrates with the unique rock that lines the edge of the Iowa River. The deck and railings have been replaced, but superstructure and substructure of the bridge retain excellent historic integrity. This is a historic bridge that fits in beautifully with its natural and man-made surroundings, including the scenic rocky Iowa River and the other historic arch bridges in town.
Despite the importance of this historic bridge to the city of Iowa Falls, and despite the high level of historic significance this bridge carries, Iowa DOT has designed a plan to demolish this historic bridge and replace it with a modern structure with no heritage or historic value whatsoever. This is most unfortunate. Rehabilitation projects were completed successfully with the other two arch bridges in the city, and it seems likely this bridge could be rehabilitated if engineers were able and allowed to apply some creativity to their work. There does appear to be a need to have a wider bridge, but this could have been accomplished by building supplemental arches next to the existing arch bridge. This would have altered and diminished the historic integrity of the historic bridge, however not as severely as demolition of the historic bridge will. Further, widening the existing bridge would have retained the same bridge shape and profile. In Michigan, MDOT has done this with the Dort Highway Bridge.
Like most historic bridge demolition projects that have to deal with Section 106 and/or a community that wants their bridge preserved, a "context sensitive" bridge has been designed. Context sensitive bridges range from putting decorative lighting on the new bridge to building something other than the usual slab of concrete that composes most modern bridges. While these efforts may result in a rare example of a modern bridge that is something less then nauseatingly ugly, they never manage to convey the beauty of the historic bridge they are replacing, often because even if the overall design is interesting, modern bridges lack an attention to detail and the bridges look very plain. The proposed new "context sensitive" bridge is a steel through arch. While the overall shape of this bridge may be a decent-looking as modern bridges go, this plain and unadorned structure is nowhere near as beautiful as the historic bridge, nor will this bridge have any heritage/historic value. It would have been nicer to see engineers devote their time to forming a creative rehabilitation project that would repair and widen the existing bridge.
One interesting feature of the historic bridge is that it is practically built right into the solid rock which lines the Iowa River in this area, with hardly any man-made abutment work visible on this bridge. Instead, a portion of the rock itself appears to have been removed to fit the arch ribs in. However, this removal of rock was done carefully and efficiently, and indeed a section of the rock was left in place between the two arch ribs at the base of the bridge because its removal was not needed. As a result, this bridge is an excellent example of how in the past bridge builders used the environment and surroundings of the bridge to their advantage. In this sense, while there may have been a greater amount of pollution and environmental contamination (like lead paint) during this period in history, bridge construction activities did not damage or alter natural physical geography directly as much as it done today. Here in the modern era, the physical geography around a bridge construction site is merely something to be destroyed to fit the bridge, rather than having the bridge coexist, and perhaps even take advantage of the natural geography. Indeed, this is a striking contrast to the proposed new bridge which includes a massive concrete abutment that will cover up the beautiful, natural rock and provide a more traditional concrete abutment.
Below is a link to a rendering of the replacement bridge.
Information and Findings From Iowa's Historic Bridge Inventory
Discussion of Bridge
This long-span concrete structure spans the Iowa River in Iowa Falls. Carrying U.S. Highway 65 (Oak Street) in this mildly urban setting, this open spandrel arch features two massive ribs, upon which are borne a series of paneled concrete columns. The Iowa State Highway Commission described the bridge as the "longest arch span either concrete or steel in the state of Iowa." The 255-foot long Iowa Falls Bridge, dating to 1928, was built by the Weldon Brothers Construction Company at a total cost of $51,374.98. The construction contract was awarded to the Iowa Falls firm on 9 July 1927 by the Iowa Department of Transportation. The state highway commission used this banner headline to depict the concrete landmark: "Nature Gives Scenic Beauty Touch to New Jefferson Highway Bridge at Iowa Falls." Since its completion, the Iowa Falls Bridge has carried a steady stream of urban traffic with minimal alterations.
"Iowa Falls residents are fortunate in having the most beautiful and most picturesque section of the Iowa River thru the heart of the town," the state highway commission stated in 1927. Although highway commission engineers typically used riveted steel trusses for medium-span river crossings in rural settings, they used concrete open spandrel arches for a number of urban and small town structures in the 1920s. The Mederville Bridge, built in 1918, was apparently the first of these, designed as an alternate to a steel truss bridge. This was followed bye the Adair Viaduct in 1923 and this bridge in 1928. By using open spandrel arches, ISHC could achieve a relatively long span at a reasonable cost, while contributing aesthetically to the urban settings in which the bridges stood. But given the restrictive parameters of the arches' use--urban setting, long-span crossing, sufficient vertical clearance--only a few were built during this period. The Iowa Falls Bridge is distinguished as a well-preserved example of this application of urban bridge design. A centerpiece for this small city, it is a local landmark and an important transportation-related resource [adapted from Crow-Dolby and Fraser 1992].
Bridge Considered Historic By Survey: Yes
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