Design Process

The requirements to build a bridge on the BridgeDesigner App are as follows: build a bridge with deck 12 meters above water, standard abutments, no pier, no cable anchorages, medium strength concrete, standard two lanes, Pratt Through truss, carbon steel components, compression force/strength ratio cannot exceed .40 (+/-.01), tension force/strength ratio cannot exceed .45 (+/-.01), 15% of bridge of members hollow tubes (+/- 1%), and at the lowest possible cost.

With this in mind, we decided to use the Pratt Through Truss design with a deck height of 12 meters and change the size and tube type to create the smallest costing bridge that would still meets safety requirements. Through trial and error of testing different components of the build for 2-3 days, we were able to create a bridge that costs around $291,000 and meets all the safety requirements necessary.

The requirements to build a truss bridge using ModelSmart3D software are as follows: 4 foot balsa wood bridge, spans a 3 foot space, minimum clearance of 1ft across the span, hinge or roller end supports, and maximum load capacity. We went with 6 inch sections in order to make the process go easier. The pieces in the center were squares with diagonals, and the ends were 6 isosceles right triangles. The bridge is 1 foot wide. We decided to add extra support in the "roof" and "floor" as well to help increase its strength. After building the bridge, we went through several rounds of testing to decide the best thickness for the wood in order to increase the bridge's maximum capacity.

Using TinkerCad, we were asked to design a 3D model of the final bridge and later use Polar3D to transmit our TinkerCad design to be printed by Instructor’s 3D printer. Through clever copy-and-pasting, as well as efficient joining of objects, after making a only single square with an "X" cross section through it, and a single triangle to branch the main structure from the support, we were able to construct the entire design. This was possible because the whole structure is made up of 18 cross sectioned squares and four triangles, so all we needed to do was to create those two shapes, duplicate them, and then assemble them in the right order. The triangle is made out of a solid wedge and a "hole" wedge, offset to create a sideways v shape, seen on the far left and right side of the bridge, the pattern of cross sectioned boxes was build in a few steps: first, the main box was formed from a solid cube and a "hole" cube. Then, a cube was shrunk down into a pillar in the form of an elongated rectangular prism. That shape was duplicated and connected with it's original to form a "+." This shape was rotated 45 degrees to form an "x,' which was grouped with the box. This combination was duplicated 18 times to form the walls, the floor, and the roof of the bridge

For the research paper, we first decided to come up with the main talking points, or sections. When thinking about the design process of structures, our first thought was to include sections leading up to the future of civil engineering. This gave us our main sections named: Introduction, Civil Engineering, Bridge Design, Bridge Design Basics, Famous Bridges, Future Developments, and the Conclusion. In the first section after the introduction, we began to explain what civil engineering is and the different types. We then went into bridge design explaining the different models and simulations used in the design process and covering the basic types of bridges. We named some famous bridges and explained some of the ways they common bridge design properties. We ended it with what the future has in store for civil engineering and structural designs. Each person took assigned sections to complete the research on time.