Lateral Cyclic Behavior of SRC-RC Hybrid Columns Bending around Strong and Weak Axes: Effects of Embedment Lengths

Abstract

Hybrid columns with partial structural steel-reinforced concrete (SRC) and reinforced concrete (RC) sections in the transfer stories of buildings are prone to premature shear failure due to sudden changes in load bearing and stiffness properties. An experimental program was undertaken in this study to investigate the influence of the length of embedment of structural steel in hybrid SRC-RC columns bending around strong and weak axes. Five large-scale specimens with varying lengths of embedded structural steel were tested under gradually increasing lateral cyclic displacements and constant axial load. The main parameters studied were the failure mechanism, hysteretic response, energy dissipation potential, and lateral stiffness of test specimens. Test results showed that all SRC-RC specimens, irrespective of the direction of lateral loading, had higher lateral strengths than the RC columns. However, specimens with the lower embedment of structural steel performed poorly due to shear-dominated failure. Test results also highlighted the detailing requirements for lateral ties in the zone where structural steel was not present to promote the flexural mode of failure. Numerical analysis based on finite element modeling was carried out to predict the strength and failure mechanism of SRC-RC columns. Based on the findings of this study, recommendations are suggested for the design and detailing of these columns for practical applications.