Week 9 Blog Post

Last week in lab, we made some major changes to our three-foot bridge design. We made these changes primarily to cut down on the bridge's overall cost. Another reason we implemented such major changes is to compensate for the additional constraint of a 2''x3'' rectangular space through the bridge. This constraint was added to simulate the construction of an actual bridge, allowing an area for vehicles to travel over. The biggest difference between our original bridge and the new bridge is the removal of all grooved gusset plates. We removed these pieces to significantly cut down on cost, being that the grooved plates were twice the price of standard gusset plates. After testing our new, three-foot bridge, we found that it was able to support 42.3 lbs. This was an incredible improvement being that our three foot bridge was able to hold more weight than our two foot bridge at almost the same cost. Needless to say, we will use the newest design for the competition.
The term is almost complete. Looking back, I learned a great deal about bridges, bridge design and bridge testing. I learned the most about truss bridges. I now know why truss bridges are so commonly used. They are able to support the most amount of weight due to their design. I also learned that you cannot simply judge a bridge's effectiveness by how much weight it can support, but you must also take into account the cost of the bridge. The cost-to-weight ratio is possibly the most efficient way to measure a bridge's effectiveness by comparing the bridge's overall cost to the maximum amount of weight it can support. Another important thing I learned was how to calculate weight distribution. Weight distribution is a very important set of calculations to perform when designing a bridge. These calculations will be able to determine how and where a bridge distributes weight in the form of tension and compression. The things I learned in this class will stay with me throughout my career as an engineer and I'm very thankful I had the opportunity to work with bridges.