Cardington Denmark Martel Road Bridge North

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge carries a 1 lane, rural road over a stream in a sparsely developed, rural setting. The road appears to be have a higher volume of traffic than many other rural roads.

Physical Description

The 1 span, 72'-long, rivet-connected Warren with verticals pony truss bridge is supported on stone abutments that may well predate the superstructure. While the truss lines are traditionally composed, the floorbeams are suspended with U-shaped suspenders rather than being framed into the lower panel point gusset plate. The suspenders are a 2000 in kind replacement. The plank deck is 15'-5" wide.

Integrity

Some holed section in lower chord battens.

Summary of Significance

The 1910 York Bridge Company riveted Warren with verticals pony truss bridge is historically and technologically significant because of the rare, transitional detail of pin connected floorbeams. It is one of eight examples in the state with the detail but the only one that is not railroad related. Any connection between this bridge and the B&O Railroad that placed the other bridges is not known at this writing. The Morrow County bridge is the only one documented to a fabricator. This is a rarely seen feature on otherwise riveted bridges. The connection is by means of a single suspender/hanger over a traditional pin, a detail that recalls earlier means of field connections. This suggests that the bridge design is transitional and that using the simple pinned connection expedited erection. Whatever informed the decision, the detail is uncommon and reflects experimental thinking the Warren pony truss bridge design. The detail is also seen on a series of 1904-07 B&O RR mainline overpasses in Ashland, Medina, Trumbull, and Portage counties.

Warren trusses are the most common truss design found in Ohio and the nation. The Ohio Phase 1A survey (2008) has identified more than 500 examples dating from 1897 (25XXXX1 and only 19th century example) to 1961, accounting for well over half of the approximately 800 pre-1961 metal trusses. The Warren design was particularly well suited to rigid (riveted, and later welded connections), but not as well suited to pin connections. This helps to explain its popularity in the 20th century rather than the 19th century, although it is based on a British patent issued to engineers James Warren and Willoughby Monzani in 1848. In the U.S., the popularity of the Warren truss coincided with improvements in pneumatic field riveting equipment starting about 1900. The Warren design, which is based on a series of equilateral triangles, is identified by its simplicity of design, ease of construction with equal-sized members, and ability of some diagonals to act in both tensions and compression. A bridge with riveted field connections is rigid and thus stronger than a pin connected bridge. It also better accommodates secondary stresses.

Warren trusses were a standard design of the Ohio State Highway Department in the 1910s and 1920s, but the design achieved greatest popularity with county engineers starting in the early 1900s. The counties purchased the bridges from Ohio fabricators such as the New Columbus Bridge Co., Champion Bridge Co. and the Mt. Vernon Bridge Co. Despite the popularity of the Warren truss bridge, fewer than 12 rivet-connected Warren trusses date prior to 1910 have been identified in Ohio, and they represent the period when the rivet-connected design solidified its position as the most popular prefabricated county truss design. The design was also popular with the railroads for the same reasons; it was efficient and economical.

Justification

The bridge has a rare construction detail that appears to be transitional from pinned to riveted field connections. The same floorbeam connection detail is used on a series of 7 B&O main line overpasses, but this example is the only one that is not railroad related. Its fabricator is documented.

Bridge Considered Historic By Survey: Yes, High Significance