Today was the first day working on the bridges. My only goal was just to get a working bridge and I chose to start with a Pratt truss bridge. One of my main goals starting this contest off was to find the cheapest bridge type and also then the best way to use materials. With the Pratt truss I learned it definably wouldn't be the cheapest but I learned how useful and cost effective hollow members were. Cost for design 1, $332,482.88

This was my second bridge type that I made. It is the Pratt Truss flipped and its not as tall. Here I continued with testing different materials and hallow and solid beams. I also wanted to test with no vertical beams. Cost for design 2, $285,301.31

This is my third bridge type. By now I learned that keeping the bridge on top would be cheaper overall and then wanted to try an angled top. Cost for design 3, $275,695.81

Cost for design 4, $230,404.52

Cost for design 5, $205,815.66

Today I started working on my final bridge design. I incorporated every thing id learned so far like, optimal materials and solid vs hollow members, type of bridge is better, peir is cheaper, and that building the bridge on top is cheaper. Cost for design 6, $187,212.23

This is my final design, there is not much change for day 7 except I was able to get the cost of the bridge down even more by changing the width of some members. Final cost $178,473.26