The machine weight is 17500 KgEach crane capacity is 12500 KgThe lenght of beam is 4.5m and square cross section areaMaterial of beam is ASTM A 615 Gr60Machin connect to beam in 3 pointWhat is the beam cross section area dimension?
You left out crucial information and working it out with risky assumptions takes too much work. Whatever this was supposed to mean Machin connect to beam in 3 point What is missing is whether the cranes connect to the end and the entire weight of the machine is in the middle - or is the machine attached at 3 distributed points. In addition, there has to be some condition - looking at the ASTM spec will give strength, but you have specified whether the beam is to be just at failure or 50% safety factor, etc.
