Walnut Street Bridge, Hellertown (Pa.)

Charles N. Beckel (1827-March 8, 1888) was a fabricator and master foundryman at his family’s foundry on Sand Island at Bethlehem, Pennsylvania. Beckel studied bridge design with engineer Francis C. Lowthrop of Trenton, New Jersey. He was married to Ruth Emma Greider (1827-1854) and married again in 1862 to Mary Frances Levering (1840-1894). The Beckels had three children one being Ralph Beckel. The Beckel family was prominent in Bethlehem musical society. Charles played the trombone and sang bass in the church choir. The Beckel Foundry was located on an acre of land and had excellent water supply nearby the Central Railroad of New Jersey depot. Beckel employed Lowthorp’s patented elements in many of his bridge spans including the Walnut Street bridge which is a Pratt-truss cast and wrought iron bridge. The foundry was posted for sale in February 1892 being offered by the Wolle & Kemmerer real estate agents two years before Beckel’s second wife died.

The Walnut Street Bridge is a 56-foot, 5-panel through-truss span. Its cast-iron upper cords and tall web posts flare to their midpoints to resist buckling under compressive forces. Beckel flared the upper and lower flanges from ends to center to better resist bending and stiffened the webs with raised ridges. The cast-iron continuous deck beams cantilever to one side to carry a pedestrian walk. Cast-iron is not normally used in beams because of low tensile strength. Beckel designed with refinements that successfully withstood loads, without the help of modern steel I-beams, for over 90 years. The Walnut Street Bridge probably dates from the early 1860s was moved to the site located over the Saucon Creek near Hellertown in 1879. In 1970 Northampton County replaced it with a reinforced-concrete deck girder span. The Walnut Street Bridge, designated HAER PA 206, is now located in the Grist Mill Park - North at Walnut Street, Hellertown, Pennsylvania on a 35 acre site nearby where it formerly spanned the Saucon Creek in Northampton County, Pennsylvania. This cast-iron bridge came to the attention of the Cast and Wrought Iron Bridges Recording Project of the National Park Service around 1991, a long-range program to document historically significant engineering and industrial works in the United States cosponsored by the Historic American Engineering Record and the West Virginia University Institute for the History of Technology and Industrial Archaeology. The fieldwork, measured drawings, historical reports, and photographs were prepared under the general direction of Dr. Robert J. Kapsch, Eric N. DeLong, Emory Kemp and Dean Herrin. The Recording Team consisted of Christine Ussler of the Architecture Faculty at Lehigh University as architect and field supervisor; Christine Theodoropulos of California State Polytechnic University - Pomona; Wayne Chang from University of Notre Dame; Monika Korsos from Technical University of Budapest; Robert W. Hadlow from Washington State University; William Chamberlin and Joseph E.B. Elliott from Muhlenberg College served as photographer. Lehigh University’s Civil and Environmental Engineering Department structural engineering student team was William M. Bruin, Robert J. Connor, Perry S. Green, Christopher C. Higgins under Professor Ben T. Yen. Over a couple of years they refurbished and re-erected the structural members to become the bridge now located in the Hellertown’s Grist Mill Park with the help and financial support of the Hellertown Historical Society.