Seismic Performance of Square Reinforced Concrete Columns under Combined Cyclic Flexural and Torsional Loadings

Abstract

This article presents an experimental investigation on the behavior of reinforced concrete cantilevered columns subjected to combined cyclic bending and torsional loading. Seven columnar specimens with the same structural properties were tested under various loading conditions: cyclic torsion, cyclic uniaxial bending, and combined cyclic torsion and cyclic uniaxial bending with and without a constant axial compression force. Several combinations of cyclic bending and cyclic torsion expressed in terms of the rotation–drift ratio r were applied to study the interaction between torsion and flexural capacity of columns. The result reveals that the flexural capacity decreases and the damage tends to occur upward outside the flexural plastic hinge region as the level of applied cyclic torsion increases. An empirical model for the flexural and torsional hysteretic behavior is proposed based on the experimental result.