The Construction Process

The Design

Our construction process was very interesting indeed, as we repeatedly tried different ideas only to meet with many issues along the way. Our first thought was that we were going to create an arch bridge similar to that of the simple roman arch, but we encountered one major problem with that design: the fact that we couldn't actually get it to stay between the tables without falling through; it would have been liable to slip off with only the slightest weight added to it. With that in mind, and after 2 days of wasted planning, we decided that we would instead go with a more simple idea, a bridge with a strong deck and an arch that extended across the top instead of underneath, but this too ran into issues, not necessarily in design, but because of cost practices. When we originally built the deck, it was calculated out to be approximately $1300, which would have left us about $1200 to work on the arch, but once the deck was built we recalculated the cost and found out that we were quite literally only $36 under the maximum budget, making it impossible to build any sort of arch. As a result, instead of the arch, we decided that we would take the extra length that we had off of the end of the bridge and turn it into a sort of triangular truss in the very middle of the bridge, hoping to strengthen the spot where the two lengthwise skewers met but didn't connect. This strategy actually worked out extremely well for us, and saved us a lot of time in designing the arch, therefore it actually became somewhat of a blessing that we miscalculated in the first place, though perhaps with the arch our bridge may have stood up to more weight. In order to test that theory, we would just have to rebuild it with the arch and see which turned out to be better. In the end, the bridge came out to look like the picture above.

The Materials

In an effort to get the most support possible for our bridge, we used the bamboo skewers as the base of the deck. We figured that, if all else failed, the skewers would be flexible enough to hold together the rest of the structure even under extreme weight. We used 6 skewers to accomplish this, two from end to end to cover the length requirement and three across, though separated by a few fractional centimeters, in order to reach the width requirement. We then used toothpicks to form what I'm going to dub a sideways truss, both on the underside and on top of the three skewers. It was this sideways truss that helped to void the force of torque that acted on the bridge, because the force was distribute across the triangular formations. Finally, we used a truss made out of skewers and toothpicks on the bottom of the bridge in the middle in order to stabilize the point at which the skewers of the deck met. All in all, our design process focused more on the side to side, twisting motion of the force rather than the up and down forces of weight, which in the end is what gave our bridge the edge.