{"nrhp_refnum":"12001136","name":"Bowstring Truss Bridge","other_names":["Roaring Run Bowstring Truss Bridge","Haer Va-7","King Tubular Arch Truss","VDHR File # 060-5056 and #009-5279"],"category":"structure","location":{"address":"I-81, Ironto Rest Area","address_restricted":false,"city":"Ironto","county":"Montgomery County","state":"VA","lat":37.24115976400003,"lon":-80.22419793999995,"geom_source":"nps_gis"},"listed_date":"2013-01-02","is_nhl":false,"nhl_designated_date":null,"areas_of_significance":["Engineering"],"significance_levels":["local"],"summary":{"what_it_is":"A single-span, four-panel tubular arch pony truss bridge, 55 feet long and 12 feet wide, at the Ironto Rest Area on Interstate 81 in Montgomery County, Virginia. It was fabricated by the King Iron Bridge and Manufacturing Company of Cleveland, Ohio, and erected in 1878.","why_significant":"The bridge embodies the distinctive characteristics of tubular arch bridge construction, a rare and unusual configuration. It is the only survivor in Virginia of six identical King tubular arch bridges built in Bedford County in 1878 after floods. It clearly shows the patented design concepts of Zenas King, including the 1866 patent's tension nuts. Although it has been moved, its engineering significance remains intact.","narrative":"Set within the Ironto Rest Area along Interstate 81 in Montgomery County, Virginia, this 55-foot wrought iron bridge is a tubular arch pony truss made by the King Iron Bridge and Manufacturing Company of Cleveland, Ohio. It was first built in 1878 over Stony Fork in Bedford County, where Bedford County ordered six identical bridges after floods destroyed earlier ones in 1877. It is the only one of those six known to survive in Virginia. By the 1930s it had been moved about ten miles to a second site, and in 1977 it was relocated again to its present spot, where it now carries pedestrians. Its deck and abutments date from that move, but most main structural parts are original. It was listed for engineering significance because it shows the patented designs of Zenas King, including nuts that tighten the lower chord, and because tubular arch bridges are rare. Its relocation was judged not to reduce that value.","period_of_significance":"1878","architect_builder":"King Iron Bridge Company, Cleveland, Ohio","architectural_style":"Other: Pratt Pony Truss","criteria":["C"],"status_note":"Now serves pedestrian use at the Ironto Rest Area, on concrete abutments and a wood deck installed in 1977; most main structural components are original.","vacant_flag":null,"machine_generated":true,"model":"claude-sonnet-5-5","prompt_version":"v1.0-2026-10-29","generated_at":"2026-10-29 02:52:02.848413-05","source_pdf":"https://s3.amazonaws.com/NARAprodstorage/opastorage/live/95/6819/41681995/content/electronic-records/rg-079/NPS_VA/12001136.pdf"},"photo":{"url_800":"https://nationalhistoricalregister.com/media/12001136/098938c10f-800.webp","url_1600":"https://nationalhistoricalregister.com/media/12001136/098938c10f-1600.webp","licence":"CC BY-SA 3.0","author":"Skye Marthaler","credit_html":"<a href=\"https://commons.wikimedia.org/wiki/File:Bowstring_Truss_Bridge.JPG\" rel=\"noopener\">Skye Marthaler</a>, <a href=\"https://creativecommons.org/licenses/by-sa/3.0\" rel=\"license noopener\">CC BY-SA 3.0</a>, via Wikimedia Commons","source_page":"https://commons.wikimedia.org/wiki/File:Bowstring_Truss_Bridge.JPG"},"district":null,"sources":{"nps_snapshot_date":"2026-05-22","nara_catalog":"https://catalog.archives.gov/id/41681995","wikipedia":"https://en.wikipedia.org/wiki/Bowstring_Truss_Bridge_(Ironto,_Virginia)","wikidata":"https://www.wikidata.org/wiki/Q14712058"},"indexable":true,"url":"https://nationalhistoricalregister.com/virginia/montgomery-county/bowstring-truss-bridge-12001136/"}