John Blair DJ Geoff Morgan Michael Rossol Group 7 Bridge Project John Blair DJ Geoff Morgan Michael Rossol

Bridge Design Prototype Design And Testing Final Design and Testing Recommendations and Improvements

Prototype Design Two arch design Each side was only constructed with two layers, one vertical and one horizontal

Cross Supports To connect the two sides we notched sticks and attached them to the support beams on the top and bottom of the bridge We also used fishing line to help hold the bridge together

Boxes The platform which the press would push on as well as the ends of the bridge had boxes that were composed of many, many triangles.

Alternate Designs This design was to have a solid walled arch with three different layers, two horizontal and one vertical in the middle of the other two. To connect these two sides we were going to notch the tongue compressors and insert them over the top and bottom of the two sides. 2. This design was to have an “A” frame bridge with solid sides like the first one. By having two “A”s then the load would go straight down the leg of the A and go onto the plate form and be supported.

Prototype Testing

Prototype Testing Cont.

Final Design We revised our original design in 2 key ways. One we needed to strengthen its ability to resist torsion, and design a more economic and lighter bridge. Our solution to both of these problems was to utilize “boxes” (shown at right). These boxes are not only very strong, but economic, light weight and most importantly very good at resisting torsion.

Final Testing

Final Testing Cont.

Analysis and Redesign After the test of our final design, it was apparent that our design had certain “weak” spots, despite the fact that it was structurally sound over all. Unlike any of the other bridge a single piece of our bridge (and not the rest of it) failed. In order to fix this problem, we would add another “box” to the top of our bridge (at the weak spot) in order to reinforce this weak spot and further distribute the load across the entire bridge. Feeling that this would fix our bridge we did build another “box” when tested again our bridge broke at its base (where we removed the fishing line). This showed that yet again something we underestimated was much more important then expected. It also led to the conclusion that if we use both the added box and the fishing line our bridge would perform as we initially hoped.

Bridge Testing

Conclusion As we have discussed our final design did improve, not only in strength but also in efficiency. These improvements were due to our implementation of many “boxes”. Despite our improvements our bridge did not fair as well as we planed due to a lack of support on top. With the addition of a box at the top of the arch (and a more planed out use of the fishing line) our design would again improve, but this time much more drastically.