MIT Steel Bridge team places 5th in national competition

May 27, 2011

By Debbie Levey
Civil & Environmental Engineering

Continuing its upward climb in the rankings, the MIT Steel Bridge team placed fifth in the national Student Steel Bridge Competition held at Texas A&M University May 20 and 21. The MIT team, sponsored by the Department of Civil and Environmental Engineering (CEE), was the top-ranked private university among the 48 finalists. This is the fifth year the MIT team has participated in the 20-year-old competition.

Every year contestant teams must create a 21-foot-long bridge for a specific hypothetical situation. This year’s scenario required a bridge to carry traffic over a scenic river in a state park. It had to be light and stiff without being visually intrusive, provide clearance for boats, and passageways for utility lines. Restrictions to protect wetlands during construction required the builders to sometimes work in inconvenient locations and limit the size of nearby supply depots.

Bridges are graded according to construction speed, lightness, economy (construction time and number of builders), efficiency (how well it resists deflection) and display (appearance and poster), resulting in a single overall score. As in real life, teams must constantly make tradeoffs such as deciding on a heavier design, which might result in lower scores in some categories but higher scores in others.

Co-captain Emily Moberg, a CEE senior and veteran of previous competitions, credited the team’s fine standing to a “relatively strong performance in all categories and lack of abysmal performance” in any single area. In several categories, she described MIT as “neck to neck with the schools around us; a few points better or worse would have shifted the order.”

“We were particularly proud of our unique double-pin connections, which were very stiff. This helped us have an efficient bridge with respect to weight and deflection. I think we also did a great job of building fast and efficiently,” said Moberg. “Steve Rudolph’s guidance and help were essential in getting the bridge from paper to a glorious 3-D bridge,” as was the skilled fabrication by Jimmy O'Donnell and Jimmy Duffy from Boston Bridge Services, Inc. Rudolph is a technical instructor in CEE.

CEE graduate student advisor Pierre Ghisbain praised the team’s progress in the three weeks between the regional and national competitions. After finishing second behind the University of New Hampshire in the regionals, the team made some changes. “We knew we would have to assemble the bridge just as fast, but with one fewer builder to be reasonably competitive at the finals,” he said. “It only took our team a few practice runs to accomplish this with three instead of four people, which was truly amazing.”

The team made other last-minute changes to meet the rigorous lateral stiffness requirement. Ghisbain said, “We spent a week figuring out how to cut our lateral deflection while keeping the bridge light and easy to build. This turned out to be much harder than expected, but the team didn't give up. We