McMillin Road Bridge

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge carries a 1 lane, unimproved road over a stream in a rural area of active farms. It is posted for 6 tons.

Physical Description

The 4-panel, 1 span, 58'-long and 12'-wide, wrought iron pin-connected Pratt pony truss bridge is supported on ashlar abutments. The truss lines are traditionally composed with toe-out channels with lacing for the verticals. The diagonals, end-panel floorbeam hangers, and lower chords are eye bars. This is a rare example of an eyebar floorbeam hanger used on a pony truss bridge.

Integrity

Severe impact damage.

Summary of Significance

The 1884 pin connected Pratt thru truss was fabricated by the Massillon Bridge Co. The company sold many metal truss bridges to the county with the oldest extant example of their work dating to 1883. The bridge is also one of 24 examples of the important bridge type in Morrow County with the oldest extant example dating to 1876. With its unusual eye bar floorbeam hangers, the bridge represents and early and non-standard design that makes it historically and technologically significant in the development of the metal truss bridges.

Massillon Iron Bridge Company is believed to have been established by Joseph Davenport about 1869 to market his all-iron Howe truss bridges. It was incorporated as the Massillon Bridge Company in 1873. Davenport left the firm in 1875, but it went on to become one of the several successful and prolific metal truss bridge fabricators in the region selling standard-design, pin-connected bridges to counties throughout the Midwest. In 1903, Toledo interests gained control of the company, and it was moved to Toledo and restyled the Toledo-Massillon Bridge Company. The business was moved back to Massillon in 1909, and they manufactured ships during World War I. It was acquired by the Fort Pitt Bridge Company of Pittsburgh in 1930 or 1933. The works closed in 1943. There are over 25 Massillon Bridge Co. truss bridges remaining in Ohio (2009) with the largest concentration in Morrow 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-1885 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. 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-1895 examples are less technologically significant.

Justification

The bridge is one of over 150 extant pin-connected truss bridges dating from 1874 for pony trusses and 1876 for thru trusses. Twenty six predate 1888 and represent the era of experimentation that evolved into standardized designs by about 1888. The bridge has moderate significance because it is a type that is common in Ohio.

Bridge Considered Historic By Survey: Yes