Jefferson Ave. / Huron River

County:  Wayne

City/Township:  Brownstown Twp.

Location:  Jefferson Ave. / Huron River

Year Built:  1930

About this Bridge:
The Jefferson Avenue and Harbin Drive Bridges are eligible for the National Register as an example of an assessment district project. In addition, the Jefferson Avenue Bridge is eligible as an early long-span stringer bridge.

The Covert Act, passed in 1915, authorized the state highway department to serve as the legal agent for road projects involving two or more counties. The state held hearings, let contacts, sold bonds, and took care of other administrative matters for a given project, while the affected communities established an assessment district to help fund the improvements. Assessment District No. 463, which spanned Wayne and Monroe Counties, was created to improve a section of Jefferson Avenue, an important route connecting Detroit and Toledo.

In 1930, the district and the state highway department jointly built a state reward bridge to carry Jefferson (also known as River Road) over the Huron River, the dividing line between the two counties. The new structure was designed by the state highway department. Although its design follows one of the department's standard plans, the bridge's three 55-foot spans are relatively long for that era. In the early twentieth century, the strongest I-beams manufactured by steel mills could span only 45 feet. In the late 1920s, new technology allowed mills to roll beams with deeper webs that could carry spans of up to 60 feet.

The Jefferson Avenue Bridge replaced a 102-foot swing span, a Warren truss, as well as a 45-foot Pratt pony truss approach span, both of which were in very poor condition. The swing span may have been moved to serve as a detour during the construction of the new structure.

The road grade by the new bridge was raised to eliminate the need for a movable span. The change in grade apparently necessitated a significant renovation of the adjacent Harbin Drive Bridge, which might have provided access to silica mines in the vicinity. The original construction date of the bridge is not known. In 1930, the spandrel walls and fill were removed and replaced. A new deck was built, and railings complementing the Jefferson Avenue Bridge were installed.