I'm trying to calculate the max load of a rack made of 3X3X1/4 steel tube. It is 8ft long and 4ft wide. I just want to calculate the max load (distributed load) in bending cross the 8ft and also in compression for the legs. i can't find the right formulas. can anyone help? so far i what i think to be correct MOI (I)=3.495 in^4 Section modulus=2.330 in^3 MOE (E)=29,000,000 psi ( i think this is correct but i'm not sure. just want to use low grade steel) I've looked though many sources but end up with stress=6M / (bh^2) σ - the bending stress M - the moment about the neutral axis b - the width of the section being analyzed h - the depth of the section being analyzed Not sure what M is here? and σ = (yqL^2) / (8I) where σ = maximum stress (Pa (N/m2), N/mm2, psi) y = Perpendicular distance from to neutral axis (m, mm, in) q = uniform load (N/m, N/mm, lb/in) L = length of beam (m, mm, in) I = moment of Inertia (m4, mm4, in4) so what i don't have is "q" I want to know how much "q" i can have. right?