Seismic performance of angle-steel reinforced concrete columns confined with spiral reinforcement

Angle-steel reinforced concrete columns internally confined by spiral reinforcement (SCARC) were developed to improve the seismic ductility and energy dissipation capacity. In the present study, cyclic loading tests on nine column specimens were conducted to investigate the seismic performance. The failure process and hysteretic characteristics were examined. The bending moment, deformation capacity and energy dissipation capacity were evaluated through parametric analysis of axial load level, volumetric ratio of spiral reinforcement, transverse steel configuration and types of cross section. A hysteretic model of SCARC columns based on the experimental skeleton curves and hysteretic loops was proposed. Experimental results showed that SCARC columns exhibited more satisfactory seismic performance than angle-steel reinforced concrete columns. The hysteresis characteristics, peak strength, ductility and energy dissipation capacity of SCARC columns were improved due to the increased confinement from spiral reinforcement. The developed hystereticmodel provided a reliable prediction of SCARC columns under cyclic loading. (C) 2020 The Authors. Published by Elsevier Ltd.