| Spaghetti Bridge
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AME 101 Cooks Up Spaghetti Bridges
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Just one of the AME 101-approved bridge construction materials.
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"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
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Juan Rincon's attention is riveted on his bridge as he carefully
adds the last bit of weight.
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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.
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The winning team of Kahniley Sangare, David Coolidge, and Rachel
Ward hold together their broken bridge which had survived to carry
about 108 pounds, or 40.46 times its own weight before buckling.
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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 near Olin Hall in the engineering quad with their bridges at 9:00
AM the morning of Tuesday, October 3. 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 Sangare-Coolidge-Ward emerged victorious with
their bridge proving to carry 40.46 times its own weight.
—DP & PR
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Charlie DeStefano, Cody Ives and Kari Wong display bridges built by
their respective teams.
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Noel Castellanos, Charlie DeStefano, Kate Kelly and Abhinav Chhabra
pose with their bridge one last time before the test.
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Charles Tyler waits for his turn to test withe Leslie Koehn uses the
slow time to get started on her lab report.
to their bridge.
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Student gradually adds weight on his bridge as some classmates and
Professor Ronney watch.
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