Strength and ductility of laterally confined concrete

The objective of this paper was to evaluate the strength and ductility of laterally confined concrete. To reach the purpose, the effects of the investigated parameters including concrete strength, the volumetric ratio, tensile strength, configurations of transverse reinforcements, as well as the longitudinal reinforcements ratio on the strength and the ductility of laterally confined concrete were analyzed. A three-dimension effective confinement coefficient of confined circular and rectangular columns was proposed to evaluate the effective confinement area of core concrete in both plane and elevation, and the strength and ductility enhancement factor prediction models of confined concrete were developed to evaluate the strength and ductility of confined concrete. The results showed that concrete strength, the volumetric ratio and configurations of transverse reinforcements, and the distribution of longitudinal reinforcements had obvious influence on the strength and ductility of confined concrete and only when lateral stress exceeded the yield strength of transverse reinforcements, transverse reinforcements had significant effects on the strength and ductility of confined concrete. Furthermore, the proposed strength enhancement factor and ductility enhancement factor models of confined concrete can be utilized to evaluate the strength and ductility of laterally confined concrete.