Bridge Forces
...ion of the problem, I assumed that there was no additional load (truck weight) added to the bridge. 3. General Approach: I approached this problem as any great engineer would, by first drawing a free body diagram. I did this for both parts of the problem. In the first part, I neglected member weight and in the second part, considered only member weight. I also labeled all external and reaction forces on my free body diagrams. After this, I used the equilibrium equations to solve for the unknown reaction forces (see appendices A and B). I then broke the bridge into pieces to analyze the forces on each individual member. From this, I came up with my general equations for both parts of the problem. I then used Quattro Pro to analyze my data and created graphs of my data (see appendices C and D). 4. Results: Part 1: For part one, I solved for the member forces in terms of a simulated load (P) on the bridge (appendix A). The values I calculated for each member force are: Member Force (lbs) Type of Force AB .5774P Compression AE .2887P Tension BC ZERO FORCE ZERO FORCE BE .5774P Tension CE .5774P Tension CD .5774P Compression DE .2887P Tension Using Quattro Pro, I calculated the member forces for a truck weighing ½ ton to 5 tons. I chose these because these are average vehicle weights (spreadsheet and plot in appendix C). I quickly discovered that members AB and CD have the same amount of compressive force. Members BE and CE have the greatest tensional forces, which means that the load of the truck (P) falls more heavily on these two members than the others. I concluded from this that members BE and CE should be made of some stronger material if the contractor is only concerned with the load. Part 2: In this part, I solved for the member forces in terms of the member weight (appendix B). The following chart shows the values that I calculated for the forces in terms of member weight (W): Member Force (lbs) Type of Force AB 2.887W Compression AE 1.4435W Tension BC 2.021W Compression BE 1.1549W Tension CE 1.1549W Tension CD 2.887W Compression DE 1.4435W Tension Using Quattro Pro, I calculated the member forces for member weights ranging from 500 lbs to 1000 lbs (appendix D)...