Prestressed Concrete Tests Compared With Torsion Theories

Tre he current ACI Code (ACI 318-83)' includes provisions for the design of reinforced concrete members subjected to torsion but does not contain similar provisions for prestressed concrete members. Investigations relevant to the prestressed case include those by Ewida,2 and Ewida and McMullen, 3 wherein the skew bending theory first proposed by Lessig 4 was extended and mathematical models for predicting the behavior of reinforced and prestressed concrete beams under combined loading were developed. In another investigation, Collins and Mitchell-' proposed design recommendations for prestressed and nonprestressed concrete beams in shear and torsion using the truss model first suggested by Rausch.e More recently, Hsu and Mo 7 used a stress-strain curve for softened concrete