Tompkins Bridge

Key Facts

Bridge Name	Facility Carried / Feature Intersected	Location	Structure Type	Construction Date / Builder or Contractor
Tompkins Bridge	M-50 Over Sandstone Creek	Tompkins: Jackson County, Michigan	Metal Stringer, Stationary	1927 By: Walter Toebe Company

Technical Facts

Rehabilitation Date	Structure Length	Roadway Width	Main Spans	Approach Spans
2006	65 Feet (19.8 Meters)	30 Feet (9.1 Meters)	1	None

MDOT's website lists this bridge as a concrete-encased deck girder, but it is in fact a concrete-encased steel stringer. The bridge does not feature floorbeams, and instead has a set of parallel beams, therefore it is a stringer. The beams on the bridge are not rolled and are built-up which adds to the significance of the structure. Perhaps the most noteworthy feature is that the stringers are all encased in concrete. Only the bottom flanges of the beams are visible. Concrete encased stringers were built across the nation in limited quantities as engineers experimented with different designs. Few examples remain today.

This bridge should not be confused with Michigan's more prolific stringer design as seen on bridges like the Chesaning Bridge. Those bridges only feature concrete on the outside of the outermost beam. All other beams on those bridges are not encased.

This bridge was rehabilitated by MDOT because of its historic significance. Although MDOT has demolished more than its share of historic bridges, they have also restored a fair number of bridges, setting themselves above Michigan's county road commissions in terms of historic bridge success stories.

Historic Significance Rating (HSR)

Information and Findings From MDOT

M-50 / Sandstone Creek Michigan State Highway 50 Bridge is eligible for the National Register as a well-preserved early example of a steel deck-girder bridge.

It carries a route that has been important since at least the early twentieth century. A 1911 atlas shows Clinton Road following the present path of M-50 through the area. Within six years, the road had been incorporated into the state trunk highway system; a short length through the town of Tompkins was designated a reward route. A 62-foot pin-connected Pratt pony truss with a 16-foot roadway initially carried the road over Sandstone Creek.

The contract for the present bridge was awarded in March 1927. Bid specifications called for a reinforced concrete substructure with a single-span steel deck plate-girder superstructure. Plans were prepared by the state highway department.

Walter Toebe and Company of Shingleton, Michigan, won the erection contract for $16,455.85. Bids for the structural steel from the Wisconsin Bridge and Iron Company and the American Bridge Company were identical: $4,205.89. The State Administrative Board authorized State Highway Commissioner Frank Rogers to chose between the companies, and he selected the Wisconsin Bridge and Iron Company of Milwaukee. Both the state highway department and the county road commission contributed funds to the project.

Although steel deck girder structures had been used in the state since the 1900s, the highway department did not issue a concrete-encased design until the 1927-1928 biennium. Despite the addition of modern metal guardrails along the inner faces of the railings, the present bridge serves as a good early example of a state standard plan steel deck-girder bridge.

Visit MDOT's Historic Bridge Website

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