Marsh Concrete Rainbow Arch Bridge is a

reinforced concrete Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ...

through arch bridge A through arch bridge, also known as a through-type arch bridge, is a bridge that is made from materials such as steel or reinforced concrete, in which the base of an arch structure is below the deck but the top rises above it. It can either be lo ...

over the Little Cottonwood River in Cambria Township, Minnesota, United States. The bridge is listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...

. The bridge no longer carries traffic, which has since been shifted to another bridge to the east. The bridge was designed by James Barney Marsh and built in 1911, the same year in which he filed a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

for his rainbow arch design. His design features two arched ribs, one on either side of the roadway, rising above the deck. The deck is suspended from the arches by vertical risers. Drivers see the rainbow arch crowns on each side, similar to crossing a

pony truss A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements, typically straight, may be stressed from tension, compression, or ...

bridge. The bridge over the Little Cottonwood River is one of the oldest Marsh rainbow arches in the country. Unfortunately, as traffic flow increased and farm machinery got larger, many of Marsh's rainbow arch designs became obsolete, since they could not be widened. There are only half a dozen Marsh rainbow arch bridges remaining in Minnesota.

References

{{National Register of Historic Places in Minnesota 1911 establishments in Minnesota Bridges completed in 1911 Buildings and structures in Blue Earth County, Minnesota Former road bridges in Minnesota National Register of Historic Places in Blue Earth County, Minnesota Road bridges on the National Register of Historic Places in Minnesota Through arch bridges in the United States Transportation in Blue Earth County, Minnesota Concrete bridges in the United States Tied arch bridges in the United States