Design a rectangular reinforced concrete beam to resist a total design moment Mu of 765 ft.-kips (this includes the moment due to the weight of the beam). The beam size is limited to 15 in. maximum width and 30 in. maximum overall depth. Use f′ c = 3000 psi and fy = 60,000 psi. If compression steel is required, make d′ = 2½ in.