Abstract：The stress softening effect can be found in the stress-strain curve of reinforcing bar under the cyclic load of tension and compression due to buckling, but it cannot be described by the traditional hysteretic constitutive model. Based on the Bouc-Wen model, an adjust formula of stiffness ratio is introduced, and the hysteretic constitutive model of reinforcing bar considering the buckling effect is established. Moreover, a calculation flowchart based on the Newton-Raphson method is introduced to solve the proposed model. The hysteresis characteristics of the reinforcing bars, such as the stiffness degradation, strength degradation, and compressive stress softening effect, can be described effectively and controlled by seven basic parameters in the proposed model. According to, the genetic algorithm is used to analyze the collected uniaxial tension and compression test data to identify the parameters. Considering the influence of the slenderness ratio, yield strength and ultimate strength-to-yield strength ratio, the results of identification are fitted and the formulas of the control parameters are obtained. Finally, the proposed model is verified by comparing with the experimental results.
