One year ago, Clemson University issued a challenge to the steel bridge teams of ASCE student chapters: Are you ready? This past weekend, the 47 finalists in the 2012 National Student Steel Bridge Competition (NSSBC) responded with a resounding yes!
For the fourth consecutive year I attended the finals, hosted this year by Clemson University in South Carolina on May 25th-26th. Bentley was proud to continue as a National sponsor, offering free software and tutorials to participating teams as they worked on their 2012 designs beginning last fall (See my sponsorship blog). 200 teams competed in ASCE’s regional conferences, with 47 teams qualifying for the AISC/ASCE national finals.
This year’s problem statement proposed a resort for rafters and kayakers with a bridge that allows vehicle access to the lodge and supports utilities under the deck—with enough clearance to prevent potential damage from flash floods. The design challenge also involved protection by the Department of Natural resources, thus prohibiting piers in the river, and necessitates a cantilever at one end due to geotechnical conditions.
Friday May 25th found the teams at the Madren Conference Center for registration, bridge set up and display judging. On this hot and sunny day, the teams literally felt the heat under the pavilion as they discussed their own designs while sizing up their competitors.
Saturday May 26th the competition moved to Clemson’s Fike Recreation Center, for the construction and load testing portion of the competition.
First, 3-6 team members gathered at the build stations, and carefully laid out each individual component of their bridges in the staging area. When judges start the stopwatch, they spring into action—racing the clock in an attempt to build their bridge in record time. Students run each component of their bridge, one at a time, over to the builders who scramble to construct their bridge as fast as possible. In the end, UC Berkeley posted the fastest time—a mere 4:97 minutes.
After the judges evaluate the construction, deem it sound, and record the official time (adding any penalties), each team moves their bridge to the Load Testing stations.
First, the Lateral load test: students place decking at the center of their deck span and add 75 lbs; a 50 pound lateral pull is then added, to measure the sway in the back span (which must not exceed ½ inch). The cantilever is then tested in the same manner. If the bridge passes both lateral load tests, then it goes on to vertical load tests, with 2 decking units and a preload of 100 on the backspan and 50 on the cantilever. Sway (max ½ inch) and deflection (max 1.5 inches downward) are measured, and 1400 pounds are added to the load on the back span, and another 950 added to the cantilever.
For those keeping track (and possibly playing along at home): that’s a total of 2,500 pounds placed on these 1:10 scale model bridges!
Each bridge is ultimately judged on the following steel design requirements: display, construction speed, lightness (lowest total weight), stiffness (lowest aggregate deflection), construction economy (lowest construction cost), and structural efficiency.
Congratulations to University of California, Berkeley! Their steel bridge team took 1st place in this year’s competition. In addition to Berkeley’s top construction speed, they also placed first for construction economy, second for structural efficiency, and had the third lightest bridge (131 lbs)—resulting in ranking #1 overall.
2nd Place: Massachusetts Institute of Technology
3rd Place: California Polytechnic State University, San Luis Obispo
Michigan Tech won the Lightness category (120 lbs) as well as the Structural Efficiency category
Milwaukee School of Engineering won the Display category
University of Louisiana at Lafayette topped the charts for Stiffness (Agg 0.511)
Click here for full NSSBC Results
On behalf of Bentley, I applaud all 47 teams, for superior designs and admirable performances. Their efforts in the 2012 NSSBC prove that the next generation of structural engineers is well prepared to help design and sustain the world's infrastructure.
You can read more about the competition at www.aisc.org/steelbridge. I hope to see your team next year!