Rocky Fork Bridge

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge, which is abandoned and has no deck, is located off of a dead-end road in a rural setting. There are cultivated fields to the south of the bridge. The property to the north of the bridge is wooded.

Physical Description

The 1-span, bowstring truss bridge is approximately 75' long and is 11' wide. It has a tubular arch built-up from channel sections. The lower chords are bars with bolted splices. The verticals alternate between bars with a cross-shaped section (star bars) and built-up, tapered, lattice members. The web diagonals are wrought-iron bars. The rolled floorbeams rest atop the lower chords and are held in place by bolts. The floorbeams are much wider than the bridge and extend beyond the lower chords. At the bearings, the lower chord and upper chord are received by a cast-iron connecting piece. The bridge is supported on concrete abutments.

Integrity

Extra width of floorbeams is suggestive that this bridge was relocated here and narrowed. The truss lines have excellent integrity of original design. This is a gem.

Summary of Significance

The bridge is a classic example of the Wrought Iron Bridge Company's patented tubular bowstring truss. It is 1 of 7 identified examples in the Ohio inventory (June 2009). Bowstring trusses are characterized by arched top chords and a trussed or lattice web. They rank among the rarest and most technologically significant of 19th-century metal truss designs since they appeared early in the evolution of iron bridge development and were almost always based on the patents or proprietary designs of bridge builders and engineers. The progenitor of the form was the famed engineer Squire Whipple of New York, who built the first example in 1840 over the Erie Canal at Utica. After the Civil War, Ohio was a center for the development of the bowstring with its concentration of metal bridge-building companies. Companies such Wrought Iron Bridge, Champion Bridge, Massillon Bridge, and King Iron Bridge built their reputations on successful bowstring designs with a dizzying number of variant ways of forming and connecting the truss members. The companies emerged in time to fill the burgeoning demand for an economical, prefabricated bridge for use on American roads. Bowstring trusses thus document this exceptionally inventive and technologically significant period in the development of American metal trusses from the 1860s to early 1880s. The ODOT inventory has identified 22 surviving examples dating from ca. 1864 to 1880 (Phase 1A, 2008).

Justification

The bridge is one of the 22 extant bowstring truss bridges that survive in the state. Having so many is remarkable, and even though they are "common" based on their numbers, each is an important and irreplaceable record of the development of the metal truss bridge and the ingenuity associated with the Ohio industrial development. The bridge has high significance.

Bridge Considered Historic By Survey: Yes