1. The problem statement, all variables and given/known data I'm designing a pratt bridge for class that looks like this: http://www.garrettsbridges.com/photos/pratt-truss-bridge/attachment/pratt-truss-bridge-2/ I have a two dimensional drawing of one side of the bridge. 2. Relevant equations/ 3. The attempt at a solution All of my horizontal members on the top are in compression and the bottom are in tension. All of my vertical members except the first one one each side are in compression. My diagonal members vary between tension and compression depending where the weight is placed. Is this possible?