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Spaghetti Bridge


AME 101 Cooks Up Spaghetti Bridges

Just one of the AME 101-approved bridge construction materials.
"Design and construct a bridge made from uncooked or cooked spaghetti (any brand) and Elmer's white glue." I paused to ponder what I'd just read before involuntarily glancing back to the page heading to confirm this really was an assignment for an engineering class.

As their first design project, AME's Prof. Paul Ronney assigned this task to his AME 101 class. Of course that one-sentence statement is much too simple to be a complete set of project requirements. Ronney's project specification includes a definition of spaghetti
Steven Hernandez gradually adds to the load carried by his bridge. In the background (from the left) George Huyke, Kazuma Kitagaito, Laura Wingert, Mario Endo, Christian Baker (sitting), Daniel Orr, and Joseph Lubinski observe the test, while Anthony Zanotti (on the right, facing the scale) weighs his bridge.
as "...a generally circular cross-section pasta not more than 2 mm in diameter," and a procedure for disputing the definition ("If in doubt, show me your pasta...."). In proper pedagogical form, he contrasts spaghetti with alternative structural materials: "Obviously ziti or some hollow structure would have a better strength to weight ratio, but you can laminate the spaghetti into whatever shapes you want." To illustrate thinking out-of-the-box Ronney suggests his designers consider such approaches as, "... use cooked spaghetti to build a suspension bridge with spaghetti 'cables,'" pointing out the design trade-off of the additional weight due to water in the cooked spaghetti. As there are no culinary prerequisites for AME 101, he advises the students to "[D]o some strength testing of various brands of spaghetti ... before building." Teams of up to 3 students design their bridge, documenting their activities, ideas, test results, and progress in a notebook. This notebook becomes the basis of 2/3 of the students' grades for the project.

This design project is also an intra-class competition. For the competition the bridge is first weighed, then laid across the gap between two 1" diameter cylinders laid horizontally 25" apart.
The winning team of Sharon Morad, Krista Goulding and Florian Maurer and their bridge which later survived to carry 19.7 times its own weight before buckling.
An empty bucket is suspended from the bridge and one of the team members slowly pours sand into the bucket, loading the bridge until it collapses. The bucket of sand is weighed and the ratio of the live load (weight of bridge plus load) to dead load (weight of bridge alone) is computed. The team with the highest live load to dead load ratio wins. The teams' performance in the competition contributes the final 1/3 of their grades for the project.

Teams assembled at Vivian Hall with their bridges at 2:30 PM the afternoon of Thursday, October 20. Students and onlookers gathered around the test stand as the first bridge was carefully set in place. A few minutes later a loud, "Ohhhww..." was heard as the spaghetti crumbled and the bucket of sand hit the ground. Hours later, after the last bridge had broken and the pasta pieces had been swept up, team Morad-Goulding-Maurer emerged victorious with their bridge proving to carry 19.7 times its own weight.
—DP & PR

Thomas Vangsness waits to test his bridge while Sayre Peralta and Michael McCormack grab a quick snack.
Philip De Gannes positions the weight on team DeGannes-Wright's heavy-duty bridge as Christopher Wright begins to pour sand into the bucket.
Robyn Strumpf supervises as Loni Iverson begins to add weight to their bridge.
Michael Maxwell and Matt Carter get a last look at their entry before beginning their (destructive) test.
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