Analytical Study for Concrete Confinement in Tied Columns

Abstract

The finite element method is used to study the confinement of concrete by rectangular ties in reinforced‐concrete tied columns. Eight columns are analyzed under monotonically increasing axial cumpression until failure. A general approach for nonlinear analysis of reinforced‐concrete columns based on the finite element is developed. The effects of the volumetric ratio of lateral reinforcement and the distribution of the longitudinal steel and the resulting tie configuration on the confinement action are studied. The results indicate that both the strength and ductility of tied columns increase as the volumetric ratio of the lateral ties increases. The study demonstrates that the relationship between gain in strength of the confined concrete and the volumetric ratio of the lateral steel is approximately linear. It is found that lateral confinement had no effect on the behavior of tied columns at loads less than 70% of the ultimate load. The finite element approach favorably predicted the results obtained experimentally by other investigators.