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Dunlap's Creek Bridge is the first arch bridge in the United States built of cast iron. It was designed by Richard Delafield and built by the United States Army Corps of Engineers.<ref name="jackson"> </ref> Constructed from 1836 to 1839 on the National Road in Brownsville, Pennsylvania, it remains in use today. It is listed on the National Register of Historic Places and is a National Historic Civil Engineering Landmark (1978). It is located in the Brownsville Commercial Historic District and supports Market Street, the local main thoroughfare. Due to the steep sides of the Monongahela River valley, there is only room for two short streets parallel to the river's shore and graded mild enough to be comfortable to walk before the terrain rises too steeply for business traffic.
History There have been four structures on this site. The first two collapsed in 1808 and 1820. The third, a wood-framed structure, needed replacement by 1832. ()
This bridge is constructed using five parallel tubular ribs, each made of 9 elliptical segments to form the arch.
See also List of bridges documented by the Historic American Engineering Record in Pennsylvania List of Registered Historic Places in Fayette County, Pennsylvania List of historic civil engineering landmarks
Notes
References
External links
Dunlap’s Creek Bridge: Historical Marker Database [ National Register nomination form] Dunlap's Creek Bridge: History and Heritage of Civil Engineering