Hi there, I have a problem regarding a simply supported C-section steel beam that I can't seem to get my head around. The beam is 6m long and supports a 15 Ton moving point load, the tensile yield strength of the steel is known and the structure must have a factor of safety of 3. The dimensions of the beam are W, H and T where H=2W and T=W/20. I have to use this information to find the dimensions of the C-section but after several attempts I can reach no conclusion. I think it must be something to do with the section modulus? But I can't seem to find any relationship between all the given data that can provide an answer for 'W'. Any advice or information would be much appreciated, thanks.