Numerical evaluation of compressive failure behavior of thin-walled concrete-filled steel tubes using coupled RBSM and Shell FEM

Abstract

The compressive behavior of thin-walled CFST is numerically evaluated taking into account higher D/t ratios, cross-sectional shape, and type of loading application. The evaluation was performed using a newly-developed coupled numerical model which combines the use of 3D Rigid Body Spring Model and nonlinear shell FEM to simulate the behavior of concrete and steel tube, respectively. Quantitative and qualitative validations performed showed excellent agreement with published test results. It was found that (1) confinement in square CFST can be achieved when only the concrete section is loaded, and this extends to specimen with D/t ratio of 300; and (2) an increased in axial ductility can be expected for both circular and square CFST irrespective of the type of load application.