April 05, 2005 —
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Chris Cho, center, and members of the Viterbi School steel bridge team, assemble
their masterpiece, a 21-foot long, 220-pound truss bridge. |
USC's Viterbi School placed second in this year's AISC (American Institute of
Steel Construction) Student Steel Bridge Competition by building a 21-foot-long,
220-pound truss bridge in six and a half minutes.
Six engineering students in the Department of Civil and Environmental Engineering
put their steel masterpiece together in record time at the 2005 Pacific Southwest
Regional Conference (PSWRC), held April 1 on the California State University,
Fullerton campus. A team from California State University, Long Beach, won first
place in the popular bridge-building tournament.
The competition, hosted by the American Society for Civil Engineers (ASCE), brings
together approximately 600 engineering undergraduates from 16 universities in
California, Arizona, Nevada and Hawaii, for two days of competition, presentations
and networking opportunities.
“This is a wonderful opportunity for students to share in the practical experience
of taking concepts and information taught in their engineering classes and putting
it to use,” said Raman Unnikrishnan, dean of the hosting College of Engineering
and Computer Science at Cal State Fullerton. “This provides valuable
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Joel Waters, who was on the construction team, uses a band saw to sculpt pieces
of the bridge. |
lessons that can only be achieved when actually taking concepts and knowledge
and using them in applications similar to what they will be doing in their careers.”
The design competition tests the skills of civil engineering students from colleges
and universities across the country who are learning the benefits and challenges
of using prefabricated steel in bridge construction, said USC’s John Caffrey,
a research assistant professor of civil and environmental engineering, who served
as the team’s faculty advisor. In addition to the competition, students also have
a chance to meet new people, see other schools and apply their design skills.
Serious Business
The students take the competition seriously. For months beforehand, Viterbi School
team co-captains Patrick Maguire, a senior civil engineering major, and Chris
Cho, a junior civil engineering major, welded, hammered and cut steel strips into
small, prefabricated pieces that would be fastened together during competition.
Fifteen civil and environmental engineering students worked on the bridge this
year, fashioning all of the steel pieces to fit in a box that’s only 3’6” x 6”
x 6”. Although they were allowed to weld and bolt their pieces together in the
prefabrication phase, they were only able to connect the pieces with nuts and
bolts during the competition.
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Co-captain Patrick Maguire welds a section of the truss. |
“This year our design was a single span truss bridge that's fairly heavy, but
exceedingly strong, and could be built quickly,” said Maguire, who was on last
year’s team as well. “It was heavier than some of the other bridges, but it deflected
less than one-tenth of an inch under a load of 2,500 pounds of weight.”
According to the PSWRC rules, students were able to design and scale any type
of single span bridge. Single span bridges have only two sets of footings. The
competition called for a bridge that would span an imaginary river 21 feet from
bank to bank. Students were given a site plan and elevation map of the river valley
in which the bridge was to be built. Maguire’s team picked a truss design that
stood about 5-to-6 feet tall and 4 feet wide when it was finished.
“Suspension, truss or beam bridges were all viable options,” Maguire said. “According
to PSWRC rules, the bridge itself was to be a support structure for steel decking,
which would simulate a roadway.”
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Amanda Merrick, also on the construction team, uses a drill press during fabrication.
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There are four key elements to building a winning bridge, Maguire and his teammates
explained. First, the bridge must be fully pre-fabricated prior to the competition
and fit into the specified box. Second, it must be constructed in as little time
as possible using as few people as possible. Third, the bridge must be able to
hold 2,500 pounds of weight without bending more than 2 inches under the load.
And last but not least, the bridge must be lightweight.
The Ideal Bridge
"The ideal bridge would be one that is made out of the minimum number of pieces,
thus making it very easy and quick to build," Maguire said. "It would take the
entire load without deflecting more than one-tenth of an inch, and would weigh
less than 80 pounds, because anything over 80 pounds begins to work against you.
Those were the ideal parameters we were shooting for."
The team worked long hours after classes and on weekends to design and fabricate
the 45 pieces that made up the truss. They began in September, during the first
week of school, Maguire said, sketching out designs, doing hand calculations,
modeling and running computer analyses of their creations to see how well they
performed. Caffrey helped troubleshoot various designs with the students.
The spring semester was devoted to fabrication, which included ordering the steel,
then cutting it to the required sizes, and finally welding it all together into
the pre-fabricated pieces, Maguire said. Six students were chosen to compete
in the regional contest, but they had few chances to test the bridge prior to
last week’s competition.
Seventeen PSWRC steel bridge entries were judged on stiffness, lightness, speed
of construction, aesthetics, efficiency and economy. The bridges were displayed
on Thursday, March 31, at the main entrance to California State University, Fullerton.
Judging
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Chris Cho and Kathryne Ceballos fasten two top pieces together |
took place on Friday, April 1, in the Cal State Fullerton Quad.
The first and second place teams from the regional contests will compete in the
national competition, to be held May 27-28 at Central Florida University in Orlando.
For more information about the competition, see http://www.aisc.org/.
--Diane Ainsworth
