Stress analysis with uniform stress through out a part

[sam.grayson.ubuntu]

Background:
I have a model of a bridge made out of small struts of balsa (about the size of a toothpick). I am trying to maximize the mass it can carry divided by how heavy it is. I figure the best way to do this is to eliminate any single point of failure, so the stress at every point is equal. Then there is no extraneous weight.

Problem:
I want Autodesk Inventor to calculate the amount of stress through out each strut in my model. However, using the default stress analysis tools it calculates the stress within each strut and this makes it difficult to eliminate a single point of failure because I can not assess the stress through a single strut. Is there a way to make the stress uniform through a whole strut?