ANALYSIS OF SECTIONS SUBJECTED TO COMBINED SHEAR AND TORSION--A THEORETICAL MODEL

The authors present a three-dimensional behavioral truss model capable of analyzing rectangular reinforced and prestressed concrete sections subjected to combined loading. This model employs the principles of the modified compression field theory (MCFT), and is capable of analyzing sections subjected to combined biaxial bending, biaxial shear, torsion, and axial load. Compatibility of curvatures is introduced to enable the model to handle combined shear and torsion, and to explain nonlinearity in the shear-torsion interaction curve. The model provides a check on spalling of the concrete cover for sections subjected to combined shear and torsion. Calculated deformations and ultimate loads from the model are compared with experimental results and are in good agreement.