Bridge Process - Lester

There are a lot of factors to consider when designing a bridge. West Point Bridge Designer seems simple, but almost all of the initial designs I made ended up failing even though they appeared to be structurally sound. After some practice, I discovered which designs worked and which did not, which designs were strongest, and which were most expensive. Using Knex was a whole other process. I learned how different the Knex materials were from the ideal ones in WPBD. Our design changed drastically throughout the process. We created a design using the process of elimination; if a program had existed it that could accurately model Knex-piece trusses it would have been extremely useful. Unfortunately, one did not exist, so we had to conduct hands-on trials. These trials were also informative, as we figured out which part of the bridge would fail and we used that knowledge in the subsequent design.
Engineers have to be very intuitive when designing a bridge. Something may look nice and add up to be inexpensive, but in a real trial it would fail much sooner than desired. In the truss models I had to take into account member strength, force/strength ratios, joint failure points and weight distribution. Free-body diagrams were useful in finding how much force would be applied to each joint. This knowledge is impossible to know unless the free-body diagram process, sometimes called Method of Joints, is carried out. It is a simple process but gives extremely useful information. I learned that different programs test different aspects of the design process and it is important to incorporate the best aspects of those programs in ways that fit with the intended medium (for example, WPBD designs using Knex pieces). At labs suring Weeks 9 and 10 we will test our final design and compare it to others in the class. I am not sure how much this new design will hold, but now that I have knowledge of where a bridge tends to break and how, I think this design will hold far more than our previous one.