Dr. Carson’s physics students came up with a procedure to test the load their bridge models would hold. They used a 23 lb chain, a 5 gallon bucket and weight plates from the Oxbow weight room. Once the bucket and chain were secured, students loaded weights into the bucket. It soon became clear that the bridges would hold more than the bucket, so they began stacking weight plates on top of the bridges. Model number 1 (built by Orin Mahikoa and Madison Fornwalt) held 180 lbs before breaking. Model number 2 (built by Calvin Cook and William Douglas) held 327 lbs before breaking.
Students modified their method of testing the load on bridges because the bucket could not hold enough weight. In this test, students threaded a 45 lb bar through the chain and added plate weights on either side.
The load test was modified again because load was too large for one bar. The team threaded 2, 45 lb bars through the chain and added plate weights to all four corners. They even added hand weights to the top of the bridge and plate weights on top of the bar weights. THEY COULD NOT BREAK Tobin Durham and Seth Carson’s model. The load for this model exceeds 1660 lbs. Thursday we will take this model to Heavy Equipment at River Bend to put it under the press to see how much it will hold.
The next step in the Bridge building process is the team will decide on the best model to build for the contest in March and begin to build a full size bridge for the competition.