The concrete beam is reinforced with three 20-mm-diameter steel rods. Assume that the conc...

The concrete beam is reinforced with three 20-mm-diameter steel rods. Assume that the concrete cannot suppoit tensile stress. If the allowable compressive stress for concrete is (σallow)con = 12.5 MPa and the allowable tensile stress for steel is (σallow)st = 220 MPa, determine the required dimension d so that both the concrete and steel achieve their allowable stress simultaneously. This condition is said to be 'balanced'. Also, compute the corresponding maximum allowable internal moment M that can be applied to the beam. The moduli of elasticity for concrete and steel Econ= 25 GPa and Est = 200 GPa. respectively.