Transverse reinforcement of RC columns considering effective lateral confining reduction factor

Abstract

An experimental investigation was conducted to examine the hysteretic behavior of ultrahigh-strength concrete tied columns under stress to determine the effect of the volumetric ratio of transverse reinforcements on column deformability. Eight 1/3-scale columns were fabricated to simulate a half-story of actual structural members, and their axial load ratio, transverse reinforcement configuration, and transverse reinforcement volumetric ratio were changed during the simulation. The column deformability was found to be affected by the configurations and volumetric ratios of the transverse reinforcement. The column behavior was particularly affected by the axial load ratio as compared to the amount and configuration of the transverse reinforcement. To improve the ductility behavior of an RC column using ultrahigh-strength concrete in a seismic region, a volumetric ratio of transverse reinforcement was suggested for all data satisfying the required displacement ductility ratio of over 4. The results indicate that the effective lateral confining reduction factor λ c , calculated by considering the configuration and spacing of transverse reinforcement and the axial load ratio, is reflected in the volumetric ratio of transverse reinforcements.