Newcomer Road Bridge

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge carries a 1 lane of a rural road over a stream in a rural area of active farms. The road narrows at the bridge. Posted for 6 tons.

Physical Description

The 1 span, 81'-long, wrought-iron, pin-connected, Pratt pony truss bridge has built-up compression members and eyebar tension members. Those at the end panels are connected with upturned ends through cast iron connecting pieces, a detail common to early WIBC metal truss bridges. The verticals are built up using the bulb T section that is also a hallmark of the company and was intended to make a stiffer member. One abutment is concrete and one is ashlar. The floorbeams are in kind replacements, otherwise the bridge appears to be complete. The floorbeams appear to be original to the bridge. The waterway has migrated.

Integrity

Rehabilitated in 2000 but remarkably complete. Has not been painted in many years. There is impact damage to the upstream truss.

Summary of Significance

The 1874 pony truss is a very early and very technologically significant example of its type/design by a prominent Ohio fabricator. It appears to be the oldest Pratt truss highway bridge remaining in Ohio. The 2000 rehabilitation did not adversely impact the overall integrity of original design. The eligible recommendation of the prior inventory remains appropriate. The source of the date is unknown (2009).

The design, with its distinctive upper chord panel point connection details, is characteristic of Wrought Iron Bridge Co. (WIBCo) Pratt pony trusses dating from the mid 1870s to early 1890s. The design is described as "very popular" and having been built widely in an 1881 WIBCo catalogue. It is 1 of at least 12 very similar examples in the county dating from 1874 to the early 1890s.

Pratt trusses were undoubtedly the most popular truss design of the last quarter of the 19th century and continued to be built into the 20th century. The design, which initially was a combination of wood compression and iron tension members, was patented in 1844 by Thomas & Caleb Pratt. The great advantage of the Pratt over other designs was the relative ease of calculating the distribution of stresses. More significantly, it translated well into an all-metal design in lengths of less than 200'. Significant surviving examples of all-metal Pratt trusses mostly date to the last quarter of the 19th century, and they are found with thru, pony, and the less common bedstead configuration. Prior to about 1890, a variety of panel point connections were in widespread use (including bolts, cast-iron pieces, and pins), but engineering opinion was coalescing around pins as the most efficient and constructible. Many of the connection details were proprietary and associated with individual builders or companies, and thus earlier examples are generally taken to be technologically significant in showing the evolution of the design. Post-1890 Pratt trusses show a progression toward less variation in their details such that by 1900 the design was quite formulaic with few significant differences between the designs of various builders. In Ohio, Pratt truss highway bridges, whether pinned or riveted, were almost always built under the auspices of counties and local units of government; the Pratt was not a standard design of the state highway department.

In Ohio, there are 185 Pratt trusses dating from ca. 1874 to 1945 with at least 60 dating prior to 1900 (Phase 1A, 2008). The technologically significant unaltered examples of pin-connected Pratt trusses for the most part date prior to 1885 and have documented or attributed builders and dates of construction and/or significant connection or member details. Post-1885 examples are less technologically significant. Significant unaltered examples of riveted-connected Pratt trusses date from ca. 1900 to 1915.

Justification

The bridge is the oldest example of its design in the state, and it is remarkably complete. It has early details that are particular to the WIBC.

Bridge Considered Historic By Survey: Yes