This bridge is a very old wrought iron truss bridge with an 1881 construction date. However, this bridge's extremely high level of historic significance arises from its highly unusual, if not unique, truss arrangement. First, the bridge features vertical endposts, yet is NOT a bedstead. Pony truss bridges with vertical end posts are very rare. Even more rare and unusual however is this bridge's bottom chord, which within the end panels runs from its standard position below directly up to the top chord / end post connection. As such, there is no bridge material between the first bottom chord connection and the bottom of the end post. This design of bridge may be one of the last examples of its type in the country.
The bridge retains a high degree of historic integrity. The main alteration is the railings on the bridge which are not original. However everything else on the bridge appears to be remarkably complete and unaltered.
This bridge suffers from structural deficiencies, the most obvious being that one east truss is leaning outward at the southern end, and there is a crack in the iron channel of the top chord at that location also. This appears to be from vehicular collision damage. Twisting and bending of the trusses causes the bridge to become less strong which is why the superstructure has been flagged as being in Serious condition in the National Bridge Inventory. However what many people, including those working in the transportation industry do not know is that twisting and bending can often be easily corrected as part of a preservation project. Restoration of Potter Bridge is still very feasible even with this structural problem. Bridges with far worse collision-caused structural damage than Potter Bridge have been determined feasible to restore by experts in the field. Aside from the vehicular damage, the structural integrity is relatively good. The open design of the trusses and built-up beams has prevented pack rust from forming, and the rural dirt road location has prevented road salt from reaching the trusses and so there is very little section loss.
This is a very small bridge with an extremely high level of historic significance. This bridge's preservation is not only essential, it is inexpensive and easy. The bridge could be preserved in place: rehabilitated for vehicular use or bypassed by a new bridge with the historic bridge being left in place. Alternatively, relocating a bridge this small to a park or non-motorized trail for preservation and reuse would be all too easy. Given Pennsylvania's poor track record for historic bridge preservation, even with small and extremely rare bridges such as Potter Bridge, it should be assumed that this bridge is slated for demolition. It is not to late for the Commonwealth to mend its ways and choose to preserve this small but important bridge. HistoricBridges.org strongly recommends this bridge be preserved and would be happy to support anyone who has the courage to step forward and undertake it.
Information and Findings From Pennsylvania's Historic Bridge Inventory
Discussion of Bridge
The single-span, 47'-long, pin-connected Pratt pony truss bridge was built in 1881 according to the plaque, and it has vertical end posts and the floor beams placed above the lower chords. The trusses are traditionally composed, but the basic shape of the truss lines with the squared end posts and absence of lower chords in the end panels results in the need for vertical posts to transmit the reactions to the abutments. It is an archaic and uncommon design. The design does concentrate section at the middle of the truss where bending is the greatest. The bridge is historically and technologically significant based on its date of construction and design. It reflects the period of experimentation that characterized the early days of metal truss development.
Discussion of Surrounding Area
The bridge carries a single-lane road with horizontally curved approaches over a stream in a sparsely developed, wooded setting.
Bridge Considered Historic By Survey: Yes
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