A simplified procedure is presented for calculating the areas of prestressed and nonprestressed steel in flexural concrete members that are permitted to crack at the service load level. The proposed method is based on simultaneously satisfying two design criteria; serviceability and strength. Because cracking and deflection are highly sensitive to the tensile steel stress level, the serviceability criterion used here is to place a limit on the steel stress increase due to load application. Two simple equilibrium equations, in the form M = T (Id), are solved simultaneously for the areas of the prestressed and the nonprestressed steel; T is the tensile force and (id) is the lever arm between the tension and compression forces. The procedure allows for considerable flexibility in design. For example, the two equations may be used to solve for the area and tensile stress in the prestressed steel if the designer elects not to use nonprestressed steel. Also, its simplicity permits the designer to study several trial member shapes and prestress levels. The method rationally accounts for the time-dependent change in steel stresses. It is shown to give reasonably accurate results, compared with other, more detailed methods.
