N. Saginaw Rd. / Salt River

MDOT Historic Bridge Midland County N. Saginaw Rd. / Salt River

County: Midland

City/Township: Jerome Twp.

Location: N. Saginaw Rd. / Salt River

Year Built: 1932

About this Bridge:
The North Saginaw Road Bridge over the Salt River is located about one-half mile northwest of Sandord in Jerome Township. The area surrounding the bridge is dominated by thick woods. Steep banks covered with undergrowth lead down to the river. Immediately southwest of the bridge is an abandoned railroad bridge, and about 150 yards to the northeast lies a concrete, curved-chord, through girder bridge.

The North Saginaw Road Bridge is oriented on a northwest-to-southeast axis; for the cake of clarity, the following description assumes a north-south position. The bridge is a steel, eight-panel, riveted Parker pony truss. The single span has a length of 109 feet. The overall length of the bridge is 115 feet. Raised steel plates form narrow sidewalks and provide the curbing for the 30-foot-wide roadway. Steel plates make up the deck. The polygonal upper chord if formed by back-to-back channels tied with lacing, with battens near the panel intersections. The lower chord consists of two pairs of back-to-back angles connected by lacing. Two pairs of back-to-back angles joined by large plates form the verticals. Diagonals are made of two pairs of corner posts. Detached Armco guardrails extend from all but the northwest corner. Steel I-beam stringers, riveted to the superstructure, are used for floor beams. The stringers are also I-beams, which are bolted to the floor beams. Roller bearing at the north end allow for expansion. Concrete abutments support the structure. The back- and wingwalls are also concrete. Bottom lateral bracing is provided by angles. The physical condition the the bridge is good, and the historic integrity has been maintained.

The North Saginaw Road Bridge was erected in 1920 to carry U.S. 25 over the Belle River in St. Clair County. Original bridge plans show that two identical federal-aid bridges were built that year in St. Clair County. These are two of the first three Parker low trusses built in Michigan. Both the Sarnia Bridge Company, Sarnia, Ontario, and the Michigan State Highway Department are listed on the plans. Since the Sarnia Bridge Company's name is prominent, the firm may have been involved with the design in addition to fabricating the superstructure.

When the Belle River Bridge became inadequate for its original site, it was moved in 1932 to Midland County, where a portion of U.S. 10 was being relocated and a new bridge was needed. Materials that were added or replaced in 1932 included floor beams, about a third of the stringers, floor plates, laterals, transverse beams, curb angles and abutments. To accommodate its new site, the bridge roadway was widened from 20 feet to 30 feet. The new floor consisted of welded steel plates, called a battledeck floor. The state had only begun using this type of flooring system during the 1931-1932 biennium, so this bridge is apparently one of the first examples.

The North Saginaw Road Bridge is one of the first examples of a Parker pony truss built in Michigan and is one of only a few remaining. The only example built before the North Saginaw Road Bridge and its twin is the Hemlock Road Bridge over the North Branch of the Bad River in Saginaw County. Additionally, this bridge is significant for being one of the first bridges to have a welded steel plate floor, which was added after the bridge was moved.