Various aproximate equations have been proposed or adopted by codes for predicting fps the stress in the prestressing steel corresponding to flexural failure. This paper shows that stress-strain curves can be compared to experimental curves or curves based on minimum standards specified for the inadequacies of present equations can be more clearly seen.
Because, for all members, the additional strain in the prestressing steel must be inversely related to the c/dp ratio, this ratio can be used as a unifying factor for comparing different design procedures. The use of the c/dp ratio as the prime variable leads to a simple but general equation applicable to all prestressed concrete members whether they have supplementary tension reinforcement, compression reinforcement or compression flanges.
