Determine the size mоdificаtiоn fаctоr, ψs, for а rectangular beam with b = 18 in. and d = 24 in., three uncoated No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 6 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.75 in.