Seismic performance of lightly shear reinforced RC columns

Previous experimental studies on reinforced concrete columns subjected to cyclic loading simulating earthquake loading have shown that the columns with non-seismic details of transverse reinforcement are vulnerable to the cyclic loading. In this study, to investigate the behavioral characteristics of concrete columns with light transverse reinforcement, ten half-scale specimens were fabricated and tested under repeated cyclic loading together with axial loading. The main test parameters included axial load level, hook angle, longitudinal reinforcement ratio, transverse reinforcement ratio, and shear span to depth ratio. The performances and characteristics of the test specimens were analyzed in terms of load-drift relationship, dissipated energy, damping ratio, strain profile, drift capacity, effective stiffness, and ductility. The test results showed that the axial load level is the major parameter affecting seismic performance including the drift capacity. Based on the test results, the nonlinear modeling parameters for concrete columns presented in ASCE 41-13 were investigated using fragility analysis.