Determine the cаsting-pоsitiоn mоdificаtion fаctor, ψt, for a rectangular beam with b = 16 in. and d = 20 in., three galvanized No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 4 Grade 40 stirrups located every 10 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 2 in.