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Key Facts |
Bridge Name | Type | Road | Location | City | Crossing |
| Junction Road Bridge | Truss | Junction Road | Preble County, OH | Rural | 4 Mile Creek |
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Technical Facts |
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Construction Date |
Structure Length | Roadway Width | Builder |
| c. 1875 | 142.1 Feet | 15.75 Feet | Massillon Bridge and Iron Company of Massillon, OH |
The bowstring truss bridge represents one of the most intricate and beautiful bridge types ever built. They are the oldest type of metal truss bridge, and were most commonly built in the 1870s, as the covered bridge era came to a close, but before the pin connected Pratt truss era took off. This spectacular bridge type has been all but eliminated from the roads of today for a number of reasons. First, this bridge type was built for a relatively short period of time, mostly within a single decade, so less examples had a chance to get built in the first place. Second, because they are so old, and were built decades before the motorized car, they were not designed to hold heavy loads, and many were replaced over the decades. Third, despite their rarity, the discriminatory National Historic Covered Bridge Act provided federal funding for preservation of for the more numerous wooden covered bridges while the less populous bowstring truss bridges continued to be demolished.
Although one can hardly call the period of the pin connected Pratt truss "standardization in bridge design", the era of the bowstring was even less standardized, and represented a period of experimentation, as companies that would later bring about the pin connected Pratt era about experimented with bridge designs. As a result, bowstrings can usually be quickly associated with a builder based on their general appearance. The King Bridge and Iron Company for example built very simple and plain bowstrings. The Wrought Iron Bridge Company utilized Phoenix or Keystone columns for the top chord, and the rest was heavily latticed or v-laced as with the Blackfriars Street Bridge. The Massillon Bridge Company's bowstring bridges were noted for highly unusual top chords, which utilized a design that the company developed, which had a truss-like design that resembled the Howe configuration. This design actually has roots in a bridge itself. Read below to learn more.
There are two "Iron Howe Bridges" in Ohio and one is utterly ancient for a metal bridge, having been built in 1859. It is ironically located in Massillon, Ohio. The bridge is documented in a HABS HAER page, and the page mentions that Joseph Davenport built the bridge. Davenport later became the founder of the Massillon Bridge Company. The HABS HAER article says the design of his 1859 bridge anticipated the later development of his "Davenport Straight Howe Truss" Here is a HABS HAER photo of the bridge. Note that the design of the trusses are similar to the top chord of the Junction Road Bridge, but there are less poles making up the truss. The only other iron Howe bridge is ironically in Preble County and is the Longman Road Bridge. It is also ancient, but is newer than the 1859 bridge, having a c. 1875 date, which is the same period as Junction Road. Note that the Longman Road Bridge looks like the 1859 bridge in design, yet has more poles, much like the Junction Road Bridge. The Longman Road Bridge may indeed be the Davenport Straight Howe Truss that HABS HAER discussed, although I cannot be sure. Actually, the builder of the Longman Road Bridge is not documented either, but it must indeed be a Massillon Bridge Company Bridge, as it is so much like the other iron Howe and the bowstring's top chord, both bridges that were apparently later patented.
This bridge is a through bowstring truss bridge. It sits on concrete abutments, which may not be original, as I would expect abutments from 1875 to be something other that concrete. Perhaps cement was added on top of original stone abutments. The vertical members are made of star-shaped steel rods, which are commonly found on old bridges of the 1870s period, particularly on bowstring bridges. The sway bracing is latticed on the bridge, and represents the only lattice on the bridge. The arched top chord is as discussed above a truss in itself, and forms a Howe-like arrangement. Anyone who is curious as to how an 1875 bowstring is supporting modern traffic need only glance under the bridge at the beams running the length of the crossing. In truth this is today a beam bridge, with the trusses simply sitting on top of it all. This is an unfortunate addition, but understandable given the frailty of the bowstring truss bridge. These additions do not affect the appearance of the bridge to those who simply drive across it without actually getting out and inspecting the bridge. There are u-shape steel railings on the bridge, which may be original (or may not be) but they are nevertheless old with Jones and Laughlin stamps on the steel. There are wooden railings under the steel, which are probably not part of the original design. The deck of the bridge is wooden with an asphalt wearing surface.
