A1-CAMERON

In designing a bridge to meet the specifications of A1, my goals were to create an aesthetically pleasing bridge that was safe and cost efficient.  The most important factor was the safety, followed by cost, leaving visual appearance as my lowest priority.  The final design I chose to use, which is pictured above, was the cheapest way to incorporate all of the aforementioned goals. The picture below depicts the bridge while a truck is crossing over it.

The load test results are as follows:

When I had first begun designing the bridge, there was a very similar structure, but less structural pieces.  The cost was of course much lower, but when it came time to test the bridge it failed.  I then went to the other extreme and created far too many members to the point that it was astronomically expensive.  This final design creates a happy medium in a way that uses the minimum amount of members for this design to allow the truck to cross the river. 

At this stage, my bridge's projected cost is $429.653.47.  I expect this number to either decrease or remain somewhat stable with time and further knowledge due to the fact that the simulation shows a large amount of sagging.  I could potentially lower the cost by making the top of the trusses lower, but this could in turn create more sag.  If I add more members with a lower maximum height, I could reduce the cost by lowering the height but consequently raise the cost by adding more members; thus, maintaining a stable cost. 

Through designing this bridge, I have learned the true power of a triangle.  While in the design phase, I had experimented with parallelograms and one of two scenarios would play out.  The first scenario would be that the program would tell me that the structure was unstable and could not be tested, and the second scenario would be that the design could be tested but would have some sort of disfiguration that would cause the bridge to fail.  In very few cases did the parallelogram actually prove to be a successful design.