Before undertaking this project we decided to research popular trusses and use them to help our design process. After researching, we decided to design our bridge using a Camelback Truss, which creates a geometric curvature on the top of the bridge, dispersing the loads. We cross braced the sides of the truss, and we doubled up the dowels on the top and bottom of the bridge. Then we decided to use cross bracing along with horizontal dowels to span the width of the bridge. Our final step in manufacturing our bridge concluded after we added diagonal struts to the interior structure of the bridge. However, due to a slight manufacturing error, our bridge wasn’t completely level when resting on the table. Besides this slight error, we were happy with the finished project.
Our structures class weighted our bridges to test the maximum total loads that they could handle. As we were adding weight to the bridge, it was easy to see that the load was causing the bridge to level out. This caused a twisting motion, and it would be the eventual downfall of our design. After 33.3lbs, the bridge finally snapped and instead of breaking on a glue joint, the bridge snapped along the wooden dowels. The moments created by the unlevel bridge base caused our bridge to snap along the material. With a level base our bridge would have been able to hold more weight with the same design. In conclusion, we enjoyed this project and were happy with how our bridge performed.
After completing project two our class learned how planar trusses work and how to analyze them. With this newfound knowledge our professor tasked us to design four different truss systems that span 80 feet in scale. With my asymmetrical design I decided to use three different points along the top chord varying in distance and height. With my symmetrical design I decided to use two isosceles triangles connected in the middle with other smaller triangles. My curved design mixes the use of vertical and angled members. Finally my sloped pitch design uses only a single slope and members that are vertical braced with members at forty five degrees. This project allowed me to increase my understanding of the multiple different types pf truss systems.