Unfortunately I procrastinated too long on building this page. I have now lost most of my notes on this competition. I will explain the broad details here, and if I every find my notes will try and fill in the details.
The Competition
The competition this year was to build a draw bridge. The bridge had to be 5 feet long and a foot wide (approximately). When raised high enough to allow a certain sized object to pass (I think it was a foot square). The bridges would be compated by their strength to weight ratio. Each bridge was crushed in a machine used to test the strength of metal components. The machine measured the total force the bridge supported before suffering "catastrophic" failure.
The Team
Our team started out with the same core members as the previous year: Charlie, Jayson, and Daniel. We added Josh to the team as well.
The Competitors
Four teams entered the competition, but one did not complete their bridge on time. All four teams built solid bridges and raised the entire bridge.
- The first team built their bridge out of I beams. Each I beam was straight along the top, but bellied down along the bottom. This made for an inverted arch style design. It was a very good design and turned out to be quite strong.
- The second team built their bridge out of many straight peices a pine. There was a crossectional limit on each beam, but they got around that by using many beams. Their bridge was very strong, but extremely heavy.
- Our bridge had two main arches. Each arch was made of pine strips laminated into I beams. The road way stood ontop of the arches on pillars. A perfect arch transfers all downward stress into a compressive load. So our I beams we modeled our I beams as pillars and calculated a buckling load of about 2,000 pounds (in the end it caried over 3000 lbs.)
- The last team planned to build their bridge from balsa, but the wood did not arrive on time. At the time of the competition, they had only the two main arches built.
The Results
The second team's bridge was very strong, but was so heavy it was not really much competition. The first team's bridge did exceptionaly well. Our bridge did not hold as much weight as the first team's bridge, but it was lighter and so it won the competition.
It should be noted that the fourth team did test the strength of their arches. Their arches were very weak, but also very light. The results of the test showed that had they completed their bridge it may have won the competition.
