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A model created by two students to help celebrate the 100th anniversary of a significant local bridge will be unveiled tonight at the Williams Center for the Arts.

Robert Mattison, Metzgar Professor of Art, will open the event at 7:30 p.m. with a talk on “Roebling and the Riegelsville Bridge.” Steve Wallis Willey ’74, who serves on the committee organizing Riegelsville’s celebration of the bridge’s centennial, will talk about James Madison Porter III, professor of civil engineering, and his influence as engineering consultant on the bridge’s construction.

Also present will be mechanical engineering majors Yashpal Subedi ’05 (Dang, Nepal) and Varun Mehta ’06 (New Delhi, India), who constructed the model of the Riegelsville Roebling Bridge from balsa wood in a non-credit project supervised by Erol Ulucakli, associate professor of mechanical engineering.

Their six-foot-long rendering has piano wires to simulate steel cables and includes towers, floor spans, side railings, piers, and a suspension system. The students laid the groundwork by meeting with representatives of the Riegelsville community, taking detailed photographs of the bridge, making a scaled computer model of it, and ordering balsa wood for its construction.

After the unveiling, the model will be permanently displayed in the Riegelsville Public Library’s new historic wing. The exhibit will debut at the town of Riegelsville’s centennial celebration noon-5 p.m. Sunday. For details, call the Riegelsville Library at (610) 749-2357.

Mehta, who has been building model aircrafts as a hobby for the past six years, found the idea of working with balsa wood appealing.

“What’s been challenging about making the bridge was first trying to come up with a scaled-down computer model without having any plans, drawings, or blueprints of it,” he says. “We practically had to do everything ourselves, from scratch, by looking at the pictures we took. Another challenging aspect is that some scaled-down parts are really small and constructing them is tedious and complicated. We had to come up with efficient manufacturing techniques to complete the model in time.”

Both students also conducted EXCEL Scholars research this summer. Mehta collaborated with Jeffrey Helm, assistant professor of mechanical engineering, on a project involving digital image correlation, using equipment funded by a $243,526 National Science Foundation grant. Subedi worked with Ulucakli on the chaotic mixing of highly viscous liquids — those highly resistant to flow — with elliptical and rectangular rotors.

When approached by his EXCEL mentor about participating in the bridge project, Subedi quickly realized that the seemingly unrelated project did have relevance to his major.

“The fact that I would get an opportunity to use my favorite 3-D modeling software, AutoDesk Inventor, to model the bridge and come up with the working plans for the model inspired me the most,” he says. “After being exposed to the history of the bridge through a quick visit, I was even more proud to be associated with such a project.”

The software modeling of the bridge was difficult because of the size of the project and complexity of some of the parts, he notes.

“However, the hard work we put into the modeling of the bridge paid off soon,” says Subedi. “When the working plans were printed, they were used as accurate guides to help in production of individual model parts, eliminating the need for numerous separate calculations and measurements. Furthermore, the modeling made sure that there would be no compatibility issues between the parts when they are finally put together. Working with the minute parts certainly posed challenges because accuracy, though not required due to the simplified nature of the model, is the key to making the model pleasant to the eyes.”

Subedi is vice president of the student chapter of the American Society of Mechanical Engineering (ASME), helping organize several events related to mechanical engineering last school year. He also is promotion co-chair of the Family Weekend Planning Committee and was a resident adviser in Conway House last year. He volunteered with Habitat for Humanity in Tegucigalpa, Honduras, over spring break as a member of Alternative School Break Club.

A member of the Steel Bridge Team, Mehta serves as technical coordinator for both the ASME student chapter and the International Students Association. He writes for The Lafayette, works as an assistant in the digital media lab at Acopian Engineering Center, and sings in the College Choir and the Chorduroys, a men’s a cappella group.

In 1837, Solon Chapin and James Madison Porter, a founder of Lafayette, constructed a two-lane covered bridge in Riegelsville, Pa., that connected the town with New Jersey until the wooden structure was swept away by a flood in October 1903. The following April saw the opening of a steel suspension bridge constructed by John A. Roebling & Sons Company of New York, which achieved fame for building the Brooklyn Bridge and many other suspension bridges. James Madison Porter III, professor of civil engineering at Lafayette, was hired as an engineering consultant for the project.

The students’ model is part of a fundraiser in which people can “adopt” a component of the bridge and have their names displayed with the model in its permanent exhibition at the Riegelsville Public Library; call (610) 749-2093 for details.

Steve Wallis Willey ’74 serves on the committee organizing the celebration. He and his wife, Sharon Willey ’75, are enthused by the Porter connection.

“In 1904, the Riegelsville Bridge Company hired Porter III to inspect the newly constructed bridge,” he says. “Porter’s calculations concluded that the bridge did not meet the original contract’s load carrying specifications. From my examination of the original correspondence in the Lafayette archives, it is clear that Porter’s adverse findings were strongly disputed by the Roebling Company. Nevertheless, the bridge company decided to add the additional support cable suggested by Professor Porter. Today, 100 years later, the bridge still functions just as it was designed to.”

The Riegelsville Roebling Bridge was erected at a cost of $30,767. Spanning the Delaware River at 577 feet long and 16 feet wide, it has withstood various floods over the past century, including the raging waters of the 1955 flood caused by Hurricane Diane.

“It’s a beautiful bridge,” says Willey. “We’re proud that in ’55, when all the other bridges were out, the Red Cross and other emergency agencies set up shop because the bridge was there. One could argue that because of Porter III’s good engineering skills, the bridge is still standing.”

Featuring an “elegant silhouette with cables draped gracefully from tower to tower,” the Riegelsville Roebling Bridge is one of the few suspension bridges still in existence, if not the only one, with continuous cables. These cables of America’s first “wire rope” were developed by John Roebling on crude equipment in the meadow behind his Saxonburg, Pa., farm. Roebling’s wire rope was first sold in 1841, and later he applied it in suspension bridge designs.

For information on purchasing commemorative T-shirts, limited-edition tiles depicting the bridge, sun-catcher/ornaments with blue glass, and gold 3D filigrees of the bridge, as well as sponsorships, call (610) 749-2093. All funds raised will benefit local preservation and historical and environmental resources in Riegelsville, including the public library.


Mechanical engineering majors Yashpal Subedi ’05 and Varun Mehta ’06 \nconstructed a model of the 100-year-old Riegelsville Roebling Bridge.

Categorized in: Academic News