Benson Street Bridge

Information and Findings From Ohio's Historic Bridge Inventory

Setting/Context

The bridge carries a 2 lane street and sidewalks over a stream in downtown Lockland with a mix of industrial/commercial buildings dating from ca. 1890 to ca. 1960. I 75 is carried over Benson Street on a viaduct to the east of the bridge. At the northwest quadrant is a parking lot and a ca. 1960 commercial building. At the southwest quadrant is a ca. 1910, 1-story, brick commercial building with altered storefront. The City of Reading is located to the east side of the stream.

Physical Description

The 1 span, 100'-long, reinforced-concrete thru (rainbow) arch bridge has arch ribs with vertical reinforced-concrete hangers supporting floorbeams and a concrete deck. There are concrete pylons at the arch ends, topped by concrete light standards and lamps. The bridge has cantilevered sidewalks with galvanized pipe railings supported by concrete posts.

Integrity

Rehabilitated in 1992. Concrete repairs in kind, and replaced open-steel grid deck with concrete deck.

Summary of Significance

The 1909 rainbow arch bridge is an exceptional technologically significant example of its type/design, predating the Marsh patents, and developed by local engineer E. A. Gast. It was sensitively rehabilitated in 1992. The eligible recommendation of the prior inventory remains appropriate. It is the oldest of seven identified rainbow arches in the inventory (Phase 1A, 2008). The rainbow arch in the U.S. developed in the late 1900s and early 1910s, with its best known variation the 1912 patented design of James B. Marsh of Iowa, (which is debatably a steel arch encased in concrete). In the basic design the deck is supported by vertical hangers between the arch ribs and the floorbeams. The arch ribs, like Marsh's can have patented steel systems within them, or they can be un-patented systems of conventional reinforced concrete. The bridge type/design is known to be aesthetically pleasing and came to be popularly known as "rainbow" arches in some parts of the country, including Ohio, although technically they are perhaps best described as thru arches. The bridge type was always more numerous in the Midwest than other parts of the U.S., probably because of the influence of Marsh. The 1909 and 1911 thru arches designed by E. A. Gast in Hamilton County (3137600 & 3130622) are Ohio's oldest examples and very technologically significant as they predate the Marsh patent and are believed to have been developed independently. Later examples in Ohio are most often the design of the state bridge bureau, which developed its own standard rainbow arch by 1923.

Justification

The bridge is one of 5 remaining examples of the type that was once not uncommon in Ohio. It offered an aesthetic treatment preferred in urban and picturesque settings. The six examples date from 1909 to 1930, and this example has exceptional significance given that is the oldest precedent setting one in Ohio and one of the oldest known in the United States.

Bridge Considered Historic By Survey: Yes