Mechanical analysis and finite element modeling of FRP-ECC-HSC composite stub column under axial compression

A novel composite column, consisting of an outer fiber-reinforced polymer (FRP) tube, an inner high strength concrete (HSC) core and an engineered cementitious composite (ECC) ring, has been proposed and investigated. Compared with normal FRP-confined HSC column, the FRP-ECC-HSC composite column could exhibit superior deformability performance. In this study, mechanical analysis was firstly conducted on the composite column to investigate the interaction behavior among different components, i.e. HSC core, ECC ring and FRP tube. Modified analysis-oriented models were proposed for HSC and ECC under uniform FRP confinement. Furthermore, finite element (FE) models were also established with the use of accurate concrete damaged plasticity (CDP) model to simulate the behavior of the composite column, especially the ECC ring which is under non-uniform confinement. The material property data used in the FE models were generated by the modified analysis-oriented models. It is shown that the FE models can provide close predictions on the axial load-axial strain behavior and hoop strain-axial strain behavior compared with test results. Meanwhile, stress distribution over the composite column section as well as the influence of ECC ratio were discussed with the validated FE model.