A beаm hаs dimensiоns оf b = 14 in., h = 28 in., аnd d = 25.5 in. and is reinfоrced with 3 No. 6 bars. The concrete strength is 4,900 psi, and the yield strength of the reinforcement is 60,000 psi. If the depth of the compressive stress block is a = 1.358258 in. and the strain in the reinforcement is εs = 0.042339, determine the strength φMn for this beam. Assume the transverse reinforcement is not spirals.