3-D Modeling and Planning

The 3-D modeling of the bridge on Fusion360

This model of our bridge was modeled in Fusion360, a CAD software. The model in the software is a little different from our actual bridge, as we changed the angles in our actual design so that there were two sets of equilateral triangles in the model above, and two sets of isosceles triangles, something not in the model above. This model was constructed by sketching one truss and the roadway, extruding them to the wanted length. After the roadway was extruded, another sketch was made on the plane of the opposite side of the roadway with an identical truss to the other side. After the main structure was constructed, a sketch was made on the bottom of the roadway, where the sketch of the legs would be made.

We designed our Truss bridge to have an arch style, composed of 24 joints and 46 members in total excluding the legs. It has 20 triangles created with extra support for the middle triangle. We chose to make this design because we beileved for it to be the strongest.

This is the printed model.

This is the spreadsheet of the forces in the Bridge Designer software

This is our bridge in the Bridge Designer software

After creating the 3d model, we sketched out the truss design on a piece of paper. Using the bridge design tool that Edward used to make the model, we got all of the angles that are in the truss. We labled the angles with the same measure with the same color pen. On the far left and right are 2 equilateral triangles that are 60 degrees on each corner. The one next to each of them is a right angle triangle. The one next to it is another triangle that isn't a right angle but that was fixed in the physical prototype. Finally, the one in the center has a extra support member in the middle because most of the force being put on the bridge will have to be supported by that part.

Underneath the diagram was the calculation for the Structural Stability. We calculated one side with 12 joints and 21 members. Our final answer ended up to be 21=21, concluding that our structure is stable. However, this is just a calculation to determine how the stabilty may be, not a guarantee that our structure is 100% stable.

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