We came up with three designs for our bridge
Design 1's forces are equally spread out to prevent the bridge from breaking - hence it is the safest design. However, the design takes up a lot of space and material - hence the size may be too big and it may take a long time for the bridge to be built. There may not be enough material due to the big amount of material that we are going to use. It is easy to build.
Design 2 is an arch bridge. The load of an arch bridge is carried outward along the curve of the arch to the supports at each end. The weight is transferred to the supports at either end and hence it is very safe. However, the design uses a lot of materials for the bridge to be built and it is hard to be built.
In Design 3, the bridge is shorter but taller. The weight is not spread out very evenly. The weight is mostly on the side supports. The bridge is hence not very save and is also unable to sustain much weight due to its architecture. One good point about this bridge however is the fact that it uses less materials and is cheaper
Here is our Evaluation Matrix
With that we came up with our decision matrix