Week 7: Bridget Breslin

In week six, the Knex Bridge that was designed by the team was tested. The learned a lot from witnessing the bridge in action. We expected that the bridge would do fairly well considering it had done well in week five. In week five the bridge held roughly 36 pounds. Minor adjustments were done to the bridge to stop it from contorting and it was tested again in week six. The bridge broke not due to the weight but due to one of the end joints. The entire bridge remained intact except for the end point it broke at. Overall the bridge ended up holding 47.8 pounds of sand and had an efficiency cost of $4,341. With a few minor adjustments and the removal of unnecessary pieces the team could greatly improve the efficiency cost.

In West Point Bridge Designer, the team was able to view the weak points of the bridge with “block box” answers. This was extremely helpful when determining which areas of the bridge needed to be adjusted to make it stronger. When using the Knex to build the bridge, this feature is not available. Without specific numbers, it is more difficult to determine which regions of the bridge are under the most tension and compression. If these values were available it would tremendously help with bridge adjustments. Although the tension and compression of the bridge parts is not readily available, there are ways to calculate it. Drawing a free body diagram of the bridge could help to visualize which pieces are the weakest. Calculations from the free body diagram could then lead the team to determine the greatest tension and compression on the bridge.