The simply supported beam having a mid span cross section as shown is pre stressed by a parabolic tendon with an effective pre stress force of 233 kips. The beam has a span length of 30 ft and carries a total service load of 1.20 kips/ft, which includes the weight of the beam of 0.21 kip/ft. Calculate the outer fiber stresses at mid span under full service load. Use the gross properties of the cross section. Use the load balancing method.