This bridge is a traditionally composed example of a pin-connected pony truss. It retains good historic integrity, with the only substantial alteration being the replacement of the original railings. The Historic Bridge
Inventory says that the floorbeams were replaced in-kind in 2005. The floorbeams on the bridge look old (they are rusted similarly to the rest of the truss) and are American Standard Beams, not modern wide flange beams. If they really are
replacements, they must have been salvaged from another bridge. It is also possible that the "floorbeams" that the Historic Bridge Inventory refers to are actually the deck stringers. The deck stringers do look fairly new, and it would not
be unusual for them to be replaced as part of a deck repair.
Information and Findings From Ohio's Historic Bridge
The bridge carries a 1 lane, unimproved road over a stream in a rural area of active farms.
The 1 span, 50'-long, pin-connected Pratt pony truss bridge is supported on concrete abutments. The trusses are traditionally composed of built-up compression members and eyebar tension members. There are no
unusual details, but the bridge is wrought iron with some cast pieces, like the seats. Additional material has been welded to the end posts and upper chords. Floorbeams replaced in kind in 2005.
Impacted rust and some welded repairs in the usual places.
Summary of Significance
The pin connected Pratt pony truss bridge dated stylistically to ca. 1888 is one of 20 examples of the important bridge type in Morrow County with the oldest extant example dating to 1874. Many are undocumented
and represent the era of standardization. This example is attributed to the Massillon Bridge Co., who sold many truss bridges to the county.
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'. Prior to about 1890, a variety of panel point
connections (including bolts, cast-iron pieces, and pins), end panel floorbeam connections, and lower chord designs were in widespread use. 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 1895
the design was quite formulaic with few significant differences between the designs of various builders. This marked the end of the pin-connected Pratt's technological evolution and, in fact, it was soon eclipsed in the highway
bridge market by more rigid, rivet-connected truss designs, particularly the Warren design, but also the Pratt design as well. The transition to riveted field connections, which happened even earlier with railroads than highways,
was in no small part due to concerns about stress reversals at the pins under heavier loads and improvements in pneumatic field riveting equipment in the early 1900s. 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 1900 and have documented or attributed builders and dates of
construction and/or significant connection or member details. Later post-1895 examples are less technologically significant.
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