Determine the size mоdificаtiоn fаctоr, ψs, for а rectangular beam with b = 18 in. and d = 23 in., three uncoated No. 7 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 8 in. along the span. Assume 4,000-psi normal-weight concrete and a clear cover of 1.75 in.