Equivalent uniaxial constitutive relationship for core concrete of cross-shaped RC short columns

Abstract

Based on the experimental results of seven cross-shaped RC short columns subjected to axial load and reasonable assumptions, the core concrete in cross-shaped section was divided into several regions, the analytic derivation of the effective transverse confined pressure was provided, and the equivalent uniaxial constitutive relationship was constructed for core concrete of the divided regions. The load versus strain curves of the specimens were calculated by the proposed constitutive relationship. The calculated results agreed well with the experimental results. The effects of the tie spacing, diameter, yield stress of hoop reinforcement and section form on lateral confinement were investigated in cross-shaped sections. The results show that the tie spacing, diameter and yield stress of hoop reinforcement has significant influence on axial load versus strain curves. The axial load, peak strain, and strain ductility increase, compared with no lateral confinement of hoop reinforcement. The section form has little influence on axial load versus strain curves.