FROM THE NEST | SPRING 2024 | 33 Nearly 30 years ago when a group of Lehigh graduate engineering students discovered the historic Walnut Street Bridge in Hellertown, Pennsylvania, the structure was corroding on the banks of Saucon Creek. The students recognized the span as one of the few cast-and-wrought-iron bridges remaining in the United States and undertook a years-long journey to save it. In October 2023, they returned to the borough to celebrate the bridge’s inclusion on the National Register of Historic Places. Recognizing a Relic It was 1994 when the graduate students took a field trip to survey bridges in the area. They realized the 55-foot span was something special when they found it described in the book “Landmark American Bridges” by Eric DeLony. “Starting in 1994 and culminating in 1998, the [bridge] became a test of ingenuity, applied and practical knowledge, design principles, experience and our willingness to see this rehabilitation project to its desired conclusion,” said Perry Green ’79G ’01 Ph.D. COMMUNITY Connecting History A bridge in Hellertown, Pennsylvania, rehabilitated by a group of Lehigh engineering students has been added to the National Register of Historic Places. during his keynote speech at the event. Green, who lives in South Carolina and is retired after more than 35 years working in civil engineering, was among the students who rehabilitated the bridge. The others include William Bruin ’95G, Robert Connor ’96G ’02 Ph.D., Richard Garlock ’93G, Mike Hebor ’94G, Christopher Higgins ’97 Ph.D., Ian Hodgson ’94 ’96G, Robert Tiberi ’91 ’93G, Paul Tsakopoulos ’99G and James Van Dien ’93 ’96G. Hodgson, a senior research engineer with Lehigh’s Advanced Technology for Large Structural Systems (ATLSS) Engineering Research Center, noted the bridge has cast- iron members: floor beams, which are very unusual; verticals, top chords, lateral struts and end posts. It originally had wrought iron horizontal and vertical round rod bracing and bottom chord members that were all replaced with in-kind steel members. Restoring a Piece of History The bridge was fabricated in 1860 by the Beckel Foundry and Machine Shop of Bethlehem. It formerly connected a dirt road that eventually became West Walnut Street in Hellertown. In 1970, the county moved the bridge to make way for a paved concrete girder bridge. It was lifted in one piece by a crane and placed in a vacant field 150 feet from its original site near the Heller-Wagner Grist Mill. In 1994, the Lehigh students began the process of helping the Hellertown Historical Society, which owned the bridge, dismantle, rehabilitate and reassemble it over a mill race next to the grist mill. “It was truly a time to put what we learned in our classes to the real test,” Green said during his speech. “There were no quizzes or exams that were graded, there wasn’t any homework that needed to be turned in. What there was, was something that we discovered, and upon closer physical examination after this first trip to see this bridge, was a unique structure and worthy of further study.” The students disassembled the entire bridge, identifying what was damaged. Parts that could be repaired were transported to the ATLSS Center on the Mountaintop Campus. A new site at the head of a nature trail was chosen not more than 200 yards from the bridge’s original location. In September 1998, the bridge was re-erected there. During the 2000 Hellertown Historic Days, a ribbon cutting was held. Hodgson said the bridge provides a connection to the area’s past, and the former students always knew how special it was. “It was important to save the Walnut Street Bridge to celebrate its place in the history of the area, the contributions to bridge engineering made by the builders, and to preserve it for future generations to enjoy,” he said.—Christina Tatu Front row from left: Bill Bruin, Mike Hebor, Perry Green. Back row from left: Ian Hodgson, Rich Garlock, Rob Tiberi, Chris Higgins, Paul Tsakopoulos.
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