where c = distance from the point at which the crack. width is to be determined to the surface of the nearest reinforcement bar f = stress in the
steel, E = modulus of elasticity of the steel, h2 = distance from the point
at which the crack width is to be determined to the neutral axis, and h1 =
distance from the centroid of the tension steel to the neutral axis. Some of the
notation appears in Fig. 10.20a