Seismic behavior of steel reinforced concrete L-shaped columns under compression-bending-shear-torsion combined action

The L-shaped column is usually used as a corner column in buildings, which can be one of the weak members in the structural system. Because of the asymmetry of an L-shaped column, it is more complex in structural layout and mechanical performance. To study the seismic performance of steel reinforced concrete (SRC) L-shaped columns under compression-bending-shear-torsion combined action, twelve SRC L-shaped columns were tested in this paper. The main variables included the shaped-steel layout, the torsion-bending ratio and the ratio of limb height to limb thickness. Based on the test results, the failure modes, hysteretic curves, ductility, stiffness degradation and energy dissipation were compared and analyzed. The results show that the failure modes of SRC L-shaped columns mainly depended on the torsion-bending ratio, which could be divided into bending failure, bending-shear failure and bending-torsion failure. The shaped-steel layout had an effect on the final damage degree of the specimens. Increasing the torsion-bending ratio could improve the torsion resistance of the specimen, but the bending capacity became weaker and the stiffness degradation was faster. The ductility and energy dissipation of SRC L-shaped columns could be enhanced by reducing the ratio of limb height to limb thickness. Comprehensive analysis showed that the empty-web T-section SRC L-shaped column had superior seismic performance under compression-bending-shear-torsion combined action.