Student-designed footbridge to make
hiking trail safer, more beautiful
© Feb. 3, 2012, Norwich University Office of Communications
Hikers who wish to traverse the state of Vermont on foot will owe a debt of gratitude to two Norwich students.
Seth Knihtila and Greg McKenney, two senior civil engineering majors, are doing preliminary work on a footbridge for the Green Mountain Club [GMC], which manages Vermont’s Long Trail, a 272-mile path connecting the state’s northern and southern borders. The bridge, over the Winooski River in the town of Bolton, will allow hikers to bypass a three-mile segment that had them walking on busy roads.
“It would really eliminate a long [stretch] of walking along the highway,” said Norwich professor and project advisor Edwin Schmeckpeper, suggesting the bridge will improve safety and aesthetics for hikers.
Knihtila and McKenney won’t build the bridge, but will lay the groundwork and draw up a preliminary design for the GMC’s own team of builders. It’s the “dirty work,” according to Knihtila, of Westminster, Mass., and includes finding the precise spot to build the bridge, mapping the river, determining weight limits and combing through options for the best materials and foundational structure.
“Using these [plans], they’ll have a general idea of where to start,” he said.
A suspension bridge, consisting of a deck attached to cables stretched between four towers, sounds simple, but the amount of work involved in addressing the basic structure surprised McKenney, who comes from White River Junction, Vt. For two people who have never built a bridge before, the level of detail—such as cable types, 100-year floodplain levels and the load capacity of different designs—was unexpected. He’s not sure they will be able to accomplish everything they had planned to by the end of the semester.
“There’s a lot of things that are easily overlooked,” he said.
Not that it has been a grind. Some of the work took them into the field to visit the site and examine other Vermont footbridges. Back in October 2011, Knihtila put on a life jacket and waded out into the river with a rock tied to a line to determine the depth for a rough topographical survey.
“It got us an idea,” he said. “The river profile has no effect on our design, so it doesn’t need to be perfect.”
Both students also spent part of their winter break accompanying a drill rig that took soil borings along the riverbanks to help determine the optimal spot for the 200-foot bridge.
Schmeckpeper, a volunteer on GMC projects for years, brought the idea to the Civil Engineering Department, hoping to find students who would take it on as a senior project. He felt it was a good project because of its open-endedness. Students would have to start from ground zero and address every major concern. Good documentation from the students will help the GMC raise money and avoid mistakes, he said.
The big lesson so far? Permitting may be cumbersome but it drives everything. The GMC has been working for years to buy or secure easements on the land that will allow them to complete the project. Work continues, and land acquisition will probably drive the final cost above $1 million. While GMC is in charge of permitting, it also affects the students’ work. Knihtila and McKenney said they are studying their design in terms of ADA compliancy issues, and a possible environmental impact review may be required as well.
Dave Hardy, GMC’s director of field programs, does not believe college students have helped them design construction projects before, but said Norwich has a history with the Long Trail. Norwich, the country’s oldest military college, had an outing club back in the 1950s and 60s that used to volunteer for work on the trail system. Knihtila and McKenney’s contribution will be useful, he said, simply because GMC employees are not engineers. The students will clear up questions about site conditions, building techniques and overall design, saving them money and time.
“It’s helping us to get to where we need to be, which is quite possibly more important than money,” he said.
McKenney said his principal satisfaction came from simply being part of a very real improvement to the trail system.
“This will get used by hikers,” he said. “It will make a difference.”