Modeling of Post-yield Buckling of Reinforcement

Abstract

Finite element analysis using fiber technique was carried out to study the post-yield buckling mechanism of reinforcing bars. It was found that the softening of compressive stress takes place due to the geometrical nonlinearity associated with the lateral deformation of the compressed bars, especially after the absolute strain exceeds the yielding strain. It was clarified that the post-buckling average stress-strain relationship over the analysis domain can be specified in terms of the product of square root of yield strength and slenderness ratio of the reinforcing bar. Moreover, a unique relationship between the average stress and average strain of reinforcing bars including the effect of buckling is established through various parametric analyses. The comparison of analytical results and proposed model with experimental data showed good agreement.