TORSIONAL STIFFNESS OF REINFORCED CONCRETE MEMBERS IN PURE TORSION

A METHOD IS PRESENTED OF DETERMINING THE TORSIONAL STIFFNESS OF FISSURED REINFORCED CONCRETE MEMBERS SUBJECT TO TORSIONAL MOMENT. THE SOLID CROSS-SECTION IS REPLACED BY A HOLLOW ONE, AND STRESSES IN THE STIRRUPS, CONCRETE, AND LONGITUDINAL STEEL ARE CALCULATED AS A FUNCTION OF THE TORSIONAL MOMENT. EXPRESSIONS ARE GIVEN WHICH DESCRIBE THE INTERNAL DEFORMATION ENERGY AND THE TORSIONAL STIFFNESS, TOGETHER WITH AN EQUATION FOR CALCULATING THE VALUE OF THE TORSIONAL STIFFNESS OF A BEAM WITH ANY ARBITRARY CROSS-SECTION. THE TORSIONAL STIFFNESS VARIES WITH THE DEPTH-TO-WIDTH RATIO IN BEAMS WITH THE SAME PERCENTAGE OF LONGITUDINAL AND TRANSVERSE REINFORCEMENT. THE THEORETICAL VALUE OF THE TORSIONAL STIFFNESS OF A BEAM WITH A RECTANGULAR CROSS-SECTION WAS COMPARED WITH EXPERIMENTAL TEST RESULTS, AND RESULTS WERE FOUND TO BE IN AGREEMENT. EXAMPLES ARE GIVEN OF BEAMS WITH RECTANGULAR AND L-SHAPED CROSS- SECTIONS. /TRRL/