Simplified numerical modeling of axially loaded circular concrete-filled steel stub columns

Behavior of concrete-filled steel tubular (CFST) columns can be predicted accurately using detailed finite-element (FE) modeling, but such models are tedious to build and impractical for frame analysis. In contrast, computationally efficient fiber beam element (FBE) models can achieve the balance between accuracy and simplicity, and can be utilized for advanced analysis of structural systems. In FBE models, however, the material models themselves have to account for the interaction between the steel tube and core concrete. Therefore the accuracy of a FBE model depends mainly on the input material models. Although there are a few FBE models available in the literature for CFST columns, these models may not be suitable for some cases, especially when considering the rapid development and application of high-strength materials and/or thin-walled steel tubes. This paper proposes versatile, computationally simple, yet accurate steel and concrete models based on detailed FE modeling results of circular CFST stub columns under axial compression. The material models are then implemented in FBE modeling and the prediction accuracy is verified with a wide range of test data.