Week 9

     In the prior week our group was instructed that the gusset plates were able to become stronger with the increased number of connections. We then constructed a new bridge that partially followed our old design, but used far less amount of materials. The bridge proved to be to week and failed by twisting. The design was altered to strengthen the connections between the two sides of the bridge. This design wasn't able to hold as much weight and failed due to weak gusset plates.
     In the next week we are going to move the support that protects against twisting to the top of the bridge instead of the bottom. We will also test the bridge to see what its max load is.
     Major accomplishments for this week are having a bridge that follows our initial design, but with less materials than what we first tried. The bridge failures are also a promising factor as it shows that the bridge can vertically hold the weight; it just has a tendency to slide and twist on itself.
     The issues that have arisen are that the bridge it structural weak when horizontal forces are put on it. The problem with fixing this issue is that the solutions cause for a weaker bridge in the vertical forces. The best solution will allow for no twisting while at the same time not sacrificing vertical strength of the structure.
     What I have learned from the bridge design process is that everything aspect of design for a real bridge must be considered so catastrophes don't occur and no one is harmed. I learned that all truss designs are built out of triangles as these don't shift as squares and more sided shapes would. The forces on all the member can be broken down to see exactly what forces act on each member. The forces include tension and compression forces. I also learned that the weakest points on a bridge are the connections.

By Robert Weldon