The “Bowstring” Truss Bridge

The “Bowstring” Truss Bridge. . This small bridge is the oldest metal truss bridge and the sole survivor of its type in Virginia. It was built in 1877-78 over Stony Run in nearby Bedford County and was subsequently moved to a site over Roaring Run, also in Bedford County, where it remained in highway service until the 1970s. Moving metal truss bridges from one location to another was a common practice. VDOT moved the bridge to this location in 1977 in recognition of its historic significance as to serve as a pedestrian bridge. , The “Bowstring” Truss takes its name from the distinctive curved shape of its top “chord” that resembles an archery bow. The bridge was designed and built by the King Bridge and Manufacturing Company of Cleveland, Ohio and reflects designs patented by Zenas King in the 1860s. Here the deck components are hung from the arched top chord (the “bow”) and connected to the arch at the abutments by a lower chord (the “string”) using threaded nuts. With the top chord in compression and the lower chord in tension, any sagging of the deck can be corrected by adjusting the nuts. Unlike later metal truss bridges made from steel, the Bowstring Truss is made from wrought-iron with cast-iron connectors. , The Bowstring Truss is listed in the Virginia Landmarks Register and the National Register of Historic Places, and is documented by the Historic American Engineering Record (HAER, National Park Service) and archived in the Library of Congress. The images before you depict the bridge when it was in highway service at Roaring Run (HAER No. VA-7, 1970-71; Jack Boucher, photographer; Donald G. Prycer, James J. DePasquale, and Charles King, delineators).