Bridging history and learning at Tufts

By Kiely Quinn

For Lonetta Bartell, the Green’s Mill Bridge is more than just a bridge. “It’s a family treasure,” she says. Located where the Little Niangua River feeds into the Lake of the Ozarks in rural Missouri, the bridge was one of five constructed in the area in the 1930s to accommodate landscape changes from the newly manmade Lake of the Ozarks. Bartell fondly recalls her mother bringing her and her five siblings on camping trips beside the bridge. On these trips, “my mom would tell us stories about growing up in the backwoods of the Ozarks,” says Bartell. Since then, Bartell has taken her own children, grandchildren, and great-grandchildren to visit and camp next to the Green’s Mill Bridge.

“From an engineering sense, it’s a really interesting bridge,” says Professor of the Practice Brian Brenner of the Department of Civil and Environmental Engineering at Tufts School of Engineering. “The structure is an unusual self-anchored suspension bridge.” Brenner is always on the lookout for unique bridges to include in his courses. In 2021, he and his students developed educational resources for the Bridge of Flowers in Shelburne Falls, Massachusetts. Brenner sees the value of giving students opportunities for real world interaction and problem solving. Through class-wide projects, students get a chance to communicate with local nonprofit organizations, explore the historical and technical aspects of a bridge, and compile educational materials for the public.

This year, the class set their sights on the Green’s Mill Bridge in Roach, Missouri. “This bridge fits in perfectly because it has the design components. There’s the historical background, there’s the technical complications, and there’s an aspect of doing modern analysis of the current bridge. It was just a perfect match in all the categories,” says Brenner.

The bridge carries Camden County’s Route J across the Little Niangua River in Roach, Missouri. A tiny, unincorporated community in the Ozarks with less than 100 residents, Roach was named for a family of pioneer settlers that lived in the area. The historical structure of the Green’s Mill Bridge is the only remainder of the original five bridges on the Lake of the Ozarks. Instead of replacing the Green’s Mill Bridge, the Missouri Department of Transportation built a new bridge to the north and offered the Green’s Mill bridge for preservation. Over the years, some components of the original bridge have been replaced, such as the 1997 installation of a steel deck in place of the original timber, but the bridge structure has remained.

Despite its remote location, the bridge boasts a unique status as one of only a handful of self-anchored suspension bridges in the US. On a self-anchored bridge, the suspension cables are secured by the deck of the bridge itself, rather than into the ground. As such, the bridge is a self-contained system, which makes the design highly complex. The approach may be preferable at locations where it is difficult to build more traditional anchorages to secure the cables.

Suspension bridges are typically associated with more populous, urban settings, notes Brenner.  “Usually when you think of a suspension bridge, you think of the big city. You think of New York. You don’t necessarily associate this type of bridge with the rolling hills of the Ozarks,” he says. Unfortunately, the bridge’s points of interest initially were not enough to save it from being slated for demolition in 2016. When Bartell heard the news, she knew she had to do something to save her family treasure.     

To protect the bridge and honor its historical status, Bartell formed Green’s Mill Historical Bridge, Inc. to develop and preserve the bridge as a historic park and pedestrian bridge. Over the last several years, the group has worked with the Missouri Department of Transportation to transfer ownership of the bridge from the state to the nonprofit. Brenner first became aware of the bridge several years ago and saw an opportunity for his students to support the nonprofit by creating educational materials about the bridge.

The nonprofit aims to provide an accessible pedestrian attraction as well as educate the public about the bridge, Ozark history, and bridge engineering history in general. Tufts students approached the project from several angles, each supporting different aspects of the nonprofit’s mission. MS students Matthew Hillcoat and Jessica Lieu used deflection theory to evaluate the bridge’s readiness to act as a pedestrian bridge. Abigail Imiolek, E23, and Milli Lu, E23 created a short animation that illustrates how the bridge was originally built. Mandy Sit, E23, developed educational materials about different types of bridges in general, using the Green’s Mill Bridge as a jumping off point to teach the public about bridge architecture and engineering.

Other students dug into the history of the surrounding area and the bridge’s construction. Kevin Zhang, E23, explored the other four bridges that were built around the same time as the Green’s Mill bridge while MS student Joshua Callahan compiled an informational brochure for potential visitors to the bridge. Mallory Baus, EG23, and Nicholas Mui, EG23, created a computer model of the bridge from historical designs. In a similar vein, MS student Nathan Porter collaborated with Yuyao Guo, EG23, Marcus Hardy, E23, and Selvin Lendos, EG23, to create a 3D structural model of the bridge using the CSi bridge software. Modeling a real bridge gave the group experience solving problems that may not have come up focusing on a fictionalized scenario or problem set. For example, the group faced challenges translating the historical bridge into a modern computer rendering, since the software did not have historical section properties or material properties.

“I’d like to become a bridge engineer after school so learning how to model, load rate, and analyze bridges is an essential skill,” says Porter. The School of Engineering’s emphasis on hands-on learning gives students like Porter early experience and allows them to cultivate crucial skills for their chosen career path. Brenner’s model of partnering with nonprofit organizations provides a mutually beneficial opportunity in which students can interact with professionals and nonprofits receive materials that they may not have had the bandwidth to create themselves.

As for Bartell, the bridge continues to feature prominently in her life – she got married on the Green’s Mill Bridge a year ago. The nonprofit is currently doing a land survey, and when completed the team plans to install a range of features including nearby parking for visitors, dusk to dawn lighting on the bridge, and wheelchair access. “I just want it to be made available for future generations,” says Bartell. “People now have an idea of what they’ve got in their backyard. And I think they’re very excited about it.” As for the next project Brenner plans to focus on with his students? He’ll cross that bridge when he gets to it.

Learn more about the Green’s Mill Historical Bridge.