The simply supported T-beam shown below is used in a corrosive environment to carry a service load, consisting of 250 lb/ft dead load and 600 lb/ft live load over 40 ft. span, in addition to the self weight of the beam. Normal density concrete is used and the beam is pretensioned using multiple strands (Ap = 0.7 in) having a constant eccentricity. The prestress at transfer is 65% ultimate and the time- dependent losses are equal to 10% of the prestress force at transfer. a) [6] Calculate stresses at midspan and support sections at transfer and under final conditions. b) [2] Compare the stresses a) with relevant permissible values given in ACI-318. The concrete strengths are 4,000 psi and 5,000 psi at transfer and in service, respectively. 30 in. 20 in. 5 in. Ap = 0.7 in. 5 in. 7 in. Fig. 1. A prestressed concrete beam under flexural loads (not to scale)