Our truss was made differently from how most groups made their bridges. It was made of popsicle sticks put into a X shape, with one on the top, and one on the bottom. We put four of these individual trusses (as shown in the picture) together to make one side, meaning we used eight in total to create both sides of the bridge.
For the bottom of the bridge, there were about ten popsicle sticks horizontally, glued to two horizontal sticks under each end of the square segment. This would be one platform, out of the other five that would complete the base of the bridge.
On top of some of the base platforms are sticks going out horizontally as an effort to connect the trusses to the base of the bridge. Once the trusses were glued to the sticks connecting them to the base, the trusses were then slanted to meet in the middle as the roof of the bridge.
At the beginning stages of construction, the truss connectors were created. These connectors were made with four layers of popsicle sticks and small stick segments to keep the spacing even.
Also, the base changed from being a spread-out floor design to a more central strength design. We added an "H" shaped base that we figured would help hold more weight and distribute the pressure throughout the bridge.
We designed the base to connect to the trusses much better because the first time we had trouble connecting the floor to the trusses.
This is a photo of our bridge's roof that kept the trusses apart, unlike last time when the trusses leaned against one another.
Although we used a truss design for the second time, we decided to change the shape of the trusses from rectangles with X's to triangles. This decision was made in order to increase the strength of the trusses because triangles are very strong when weight is applied to the top vertex.
How will forces interact with our bridge?
The two major forces interacting with our bridge during the test are tension and compression. The first photo displays how these two forces interact with a single popsicle stick, but it is the same idea with the bridge. When weight is applied the bottom is pulled apart, meaning it's under tension. Tension is displayed in red in both photos. Compression pushes the top together when weight is applied, and this is displayed in blue in both photos. The trusses are meant to distribute the two forces evenly from top to bottom, thus strengthening the bridge.