FORT RIVER
SOUTH AMHERST, MASSACHUSETTS

The Fort River Bridge is a 60 ft. long span crossing the Fort River in South Amherst. The bridge originally carried traffic as part of Rt. 116 between Amherst and South Hadley, but in about 1985, the bridge was moved and rebuilt as a pedestrian bridge by the Town of Amherst. The bridge is the only surviving bridge in Massachusetts that carries the iron bridge plate indicating that it was built by the Corrugated Metal Company, the predassessor to the Berlin Iron Bridge Company. The Fort River Bridge is a 4 panel pony truss with a maximum depth at the center of 8 ft., giving an aspect ratio of 7.5. Like all other pony truss bridges examined, the vertical posts are constructed of riveted angles and plates to form an open lattice form. However, it is the only lenticular bridge in Massachusetts in which the vertical posts have parallel sides. This distinguishes it from all other pony truss bridges examined and may be a relict of the Corregated Metal Company construction. The use of tapered verticals appears to have replaced the parallel verticals in later bridges so that lighter members could be used. The bridge uses pinned connections at the end posts to tie the upper chord and lower chords together. The lower chord is constructed from 1 in. x 2 in. eye plates.