Prestressed Concrete Flexural Members: Design

An alternate method for the design of prestressed concrete flexural members using the service load criteria is presented. The method differs from other available methods, in the sense that no preliminary estimation of the prestressing force or sectional dimensions is necessary, and the range of prestress is determined prior to determining the cross-sectional dimensions or section modulus. However, the use of the design equations requires a preliminary assumption of eccentricity ratio. The method can be adopted for design of both fully stressed and non-fully stressed sections, and is applicable for pretensioned as well as post-tensioned sections. The method of construction of interaction diagrams is shown which can be used to determine the range of eccentricity in non-fully stressed sections. Different equations are derived for different types of cross sections for estimation of their thickness or section modulus.