Setting / Context:
The bridge carries a two lane street over a stream near the intersection of Campbell Avenue and SR 209 in Cambridge. The sidewalk, an original feature of the bridge, is to one side and outside of the truss lines.
The one span, 160' long, welded, Warren pony truss with verticals and polygonal upper chords is composed of all rolled section members. Because of the length of the span, channel was welded to the upper chords. Floorbeams are connected at the lower gusset plates with Dardelet bolts. The cantilevered sidewalk is supported on brackets, and it is finished with a plain metal railing. The bridge is supported on concrete abutments.
Statement of Significance:
The 1958 welded pony truss bridge is historically significant as the longest bridge fabricated by the Ohio Bridge Corporation, a prolific and notable instate fabricator of stringer and pony truss bridges for Ohioís counties. The firm is most noted for its all- welded pony truss bridges that continue to be built today based on a design developed by founder Herman Rogovin in 1946. This is the only one ever fabricated with this built-up upper chord detail. It was done to make the member stronger, which was required given the length of the span, and it stands out from the large population of Ohio Bridge Corporation bridges built in the 1950s in the state. The bridge has apparently not been altered.
Ohio Bridge Corporation was started in 1936 as the American Culvert Company at Cambridge by Herman Rogovin, who grew up in Cambridge and attended Case School of Applied Science where he received his BS in mechanical engineering in 1936. American Culvert fabricated and marketed corrugated pipe culverts to the counties and municipalities. The name of the bridge fabrication part of the business was changed to Ohio Bridge Corporation in 1952. While working at the B-29 bomber plant in Cleveland during World War II, Mr. Rogovin formulated ideas about an all-welded pony truss bridge design with rolled section members and welded shop connections that could be erected without expensive false work. He began producing that design in 1946 with the first one being placed at Millersburg (Holmes County). Dardelet bolts, a button-head bolt with a serrated center section were used for field connections. They automatically set themselves when driven in with a sledge and are locked with a nut. The bolts were used to connect sections of the truss lines into a unit and to attach the floorbeams. The pony truss bridge initially conceived by Mr. Rogovin is the one that the company continues to fabricate. Rogovin hired Sid Rockoff of Varo Engineers in Columbus to prepare the calculations and member specifications for standard truss designs in 10-foot increments between 50' to 120' in length. Standard plans were prepared for H12, H15, and H20 loading so the counties and municipalities could purchase the appropriate capacity.
Development of weld-connected truss bridges goes hand-in-hand with the development of electric arc-welding. The Westinghouse Electric Co. of Pittsburgh was a leading promoter of the technology and is widely credited with fabricating the nationís first weld-connected truss bridge in 1927-28. The arc-welding industry heavily publicized the technology, and its application to bridges spread rapidly during the 1930s. Pre-World War II examples are not rare. Ohioís 1951-1960 examples, including this one, are a continuation of a design that was well established in the state during the 1940s.
The bridge is one of over 350 extant examples of welded pony truss bridges built before 1961. It is of moderate significance based on the depth of the population and fact that most are nearly all the same Ohio Bridge Corporation design.