I have a 20' (240 inch) beam with supports at 0in., 80 in., 160 in., 240 in. I need to give the beam a rating (maximum load; capacity) since it is a monorail for a 3 ton hoist. I've asked the question to my prof (his work is attached).
I understand what the graphs represent (Bending moment due to dead load, and bending moment due to concentrated force) but I can't figure out he he got the max values (coefficients): ie. 0.08*Wdl*l^2, 0.1*Wdl*l^2, 0.025*Wdl*l^2 and second graph.. 0.07Pl, 0.175Pl, 0.075Pl
Also how does he know these act at the same position? Ie: M1, M2, M3 so that he can add them?
The Attempt at a Solution