Optimum hysteretic model selection for reinforced concrete columns subjected to rebar buckling

Abstract

Accurate prediction of the load–deformation response of reinforced concrete (RC) columns requires an appropriate hysteretic model for longitudinal reinforcement—particularly when buckling-induced strength and stiffness degradation is critical. This study provides a guidance on selecting and applying hysteretic models that capture rebar buckling by systematically evaluating three widely used models against experimental results. The accuracy of each rebar model is evaluated at both the material and element scales. Material scale validation is performed using stress–strain response data from rebars tested outside of concrete, evaluating overall response, peak strength, and the corresponding strain. Element scale validation is conducted by comparing the simulated load–deformation responses of RC columns to the associated experimental results, including the onset of rebar buckling. Based on an investigation of over 90 RC column models, the choice of rebar model should consider key parameters such as rebar slenderness, transverse rebar yield-to-concrete strength ratio, and transverse reinforcement spacing-to-section height ratio.