CIV102 Matboard Bridge

In this school assignment we were required to construct a bridge out of matboard that was able to withstand at least a 400 N train. Initially, my group and I highlighted the requirements of the handout, or "identified the contributing factors". From there, we spent a good deal of time generating ideas and planning our design. We singled out two certain cross sections, the pi and rectangular shaped, and from there we began to model these designs. After picking rough dimensions, we started to do some calculations on the predicted failure loads. I found doing these calculations by hand very tedious so I wrote a script in MATLAB to take in dimensions and return the values I was looking for. This analysis and testing led me back to the drawing board to brainstorm new designs. This time I realized that it would be very crucial to consider how the board was going to be cut and split up, instead of assuming everything would fit based on total area. Modeling the way we were going to use the board forced us to slightly decrease the dimensions. After many hours of iterating though brainstorming, sketching layouts and running the computations on MATLAB I decided on a design to use. Before making a final copy, I bought an extra tube of contact cement and made a small scale replica of our design. I wanted to do some physical testing before committing to a specific build. This prototype I made helped me realize that the areas around the point loads needed to be stronger. Based on this mistake, I made sure our final bridge was altered to account for what I learned. Sadly, I neglected the middle joint since I never noticed it to be a problem in my prototype. In terms of my personal design process, I failed to iterate through the modeling and analysis stages and was not able to reach my goal of supporting 1000 N (the "kilo-newton club"). Regardless, it was a great experience and showed me how my design process never followed a straight-cut path.

My prototype bridge built at home. Notice the failure at the two point loads, influencing the added supports in our final design.