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Moving Henszey's Bridge |
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On January 22, 2002, the upstream arch was removed from its piers and, after a brief but graceful flight over Ontelaunee Creek, was loaded onto a trailer. |
![]() Henszey's Bridge in March of 2001, as four engineering students from Bucknell University were studying it in preparation for its move from Ontelaunee Creek, near Wanamaker's, Pa., to the campus of Central Penn. |
![]() The bridge is being moved by a crew from Greiner Industries, of Mount Joy, Pa. It will be renovated in Greiner's shops there before being taken to Central Penn. In the preceding days, the crew had removed the oak decking and cut out the deck beams and trusses. Only the two bowstring arches remained. They were to be moved intact. |
![]() The upstream arch was tied to an I-beam suspended from Greiner's 130-foot tall crane. |
![]() During the first attempt to lift the upstream arch, the bottom chord began to buckle. The flat iron pieces that make up the chord were designed to pull the two ends of the arch together, like the string in a hunting bow. But as the middle of the arch was lifted from above, the ends sagged and the bottom chord began to compress. Crew leaders conferred beneath the bridge. |
![]() The camber rods on the downstream arch. |
![]() Rob Craig, Greiner's crew foreman, had some angled steel brought to the site. It was welded along both sides of the bottom chord to stiffen it. |
![]() About 3:30 the crane began lifting again. The western end of the arch came free easily, but the eastern end was stuck. While the crane operator basically wiggled it free, like a kid trying to pull out a loose tooth, Rob Craig kept an eye on the western end. |
![]() Finally the eastern end came loose and the arch lifted. |
![]() Watching the arch soar was unexpectedly exciting. You don't see airborne bridge trusses all that often. |
![]() Rob Craig scurried out on the camber rods of the downstream arch to guide the floating truss away from a tree. |
![]() Finally the truss was lowered to a 90-foot trailer. It was to be moved the following day, traveling to Mount Joy via a roundabout route that would avoid sharp turns. The downstream arch was to follow a day later. |
![]() By February 15, rehabilitation work was well underway in a vast building at Greiner's shops in Mount Joy. The trusses had been sandblasted and new floor beams had been installed (the deck will be slightly narrower than before). Metalworkers were adding new feet to angled braces that reach down from the arches to keep them vertical, and were working on the bridge's many turnbuckles. |
![]() The Bucknell engineering students struggled last year to get a look at the connections between the arches and the bottom chords. This view shows the wedge driven through the end of the bottom chord to secure it to the large cast endpiece from which the arch springs. Above the wedge is the laminated endpiece for the camber rods. Eric DeLony, chief of the National Park Service's Historic American Engineering Record, accompanied Central Penn's president, Todd Milano, on a visit to the bridge. After looking it over, Mr. DeLony said he believed that the span originally consisted simply of the arches, the straplike verticle members, and the bottom chords, and that the camber rods and their associated hardware -- including the bottom castings and assorted diagonal rods -- were added during an early rebuilding. They appear to be intended to work in conjunction with a pier supporting the bridge at its centerpoint; an old photograph of the span's twin shows such a pier at the original location, in Slatington, Pa., and the base of such a pier remains in Ontelaunee Creek, although the Ontelaunee Creek pier itself was removed in the 1930s. The system by which the camber rods are attached at the end of the bridge seems consistent with their being an addition: In this view they appear to be an afterthought. |
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![]() John Masterson, of Greiner, supplied this photo of the bridge in the company's paint shop in early April. |
![]() Late April: The freshly-painted bridge waits at Greiner for its May 7 move to Summerdale. This photo and the next were also supplied by John Masterson. |
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