Indian Trail Bridge

Visit MDOT's Page For This Historic Bridge

Researching Bridges

I have composed a formal essay that provides a look at historic bridge development, particularly metal truss bridges in Michigan, and also contains a discussion of this bridge and its history. The essay is part of the Introduction to Truss Bridges part of this website, and you can access the essay from there.

About the Bridge

This is St. Clair County's newest truss bridge, with a construction date of 1937. The Indian Trail Bridge crosses the Belle River. It is a pony truss in a warren configuration. Like many pony truss bridges, the bridge is a camelback. The bridge, according to MDOT, was built by Couse and Saunders of Detroit. The bridge originally had a concrete curb, which is gone now, due to salt damage. There are three parts to the guardrail, a metal pole, a large channel and a small channel. The largest channel was added during a 1985 repair. The other two parts are original. The bridge was last painted during these 1985 repairs as well. The analysis of the structure's integrity, which I have a copy of, suggests that the greatest loss of integrity is in the flooring system for the bridge. The trusses are in excellent condition. The deck on this bridge is 25 feet wide. The length of the truss span is 88 feet.

For some reason, someone took the time to photograph the previous bridge, which was also a truss bridge, before it was demolished. This is unusual, because I would have not expected people to document a truss bridge back in the thirties, when they were still common technology. Anyhow, the former bridge was a one span Pratt through truss bridge. The bridge had six panels. It had lattice guardrails. Plaques were mounted on the portal bracing. It sat on  masonry abutment, the remains of which are still visible today. The bridge was 96 feet long, and 14 feet wide.

This bridge, compared to the other two truss bridges in St. Clair county, is in good condition. Even so, the bridge is listed as a critical bridge. Usually this translates to the bridge being torn down as soon as the money is available. I hope that will not be so with this bridge. Although not as old as the other St. Clair truss bridges, the bridge is definitely the most restorable. Although in need of a preventative paint job, the bridge has not yet rusted severely. The northern abutment appears to be slowly being washed away and should perhaps be patched or redone. Also, since the bridge is newer, the bridge is more massive than older truss bridges, and is capable of supporting more weight. The current 15 ton weight limit on the bridge should be more than enough for a paved country road, especially when there are other larger north-south truck routes nearby. King Road is two miles away and M-29 is four miles away. These are both truck routes, and run a more direct and faster route. I am sure any of the residents in the area also would not like the idea of having those trucks on this road if the bridge were replaced with a slab with unlimited weight limit. This is a truss bridge with two lanes, so I don't see how width could be a problem.

Unlike some other states which built massive-membered through truss bridges into the thirties, Michigan built very few truss bridges after the 1910s. The Indian Trail Bridge is distinguished as a good example of late truss bridge construction in Michigan. Truss bridges from the thirties have a totally different appearance and feeling to them than to turn of the century truss bridges. They have a more massive feeling to them, but still retain a great deal of aesthetics, often in the form of extensive v-lacing and latticework. In my opinion it is just as important to preserve these bridges as it is older truss bridges. They both have something special to offer today's roadways.