Seismic performance of concrete-encased column base for hexagonal concrete-filled steel tube: numerical study

The seismic performance of concrete-encased column base for hexagonal concrete-filled steel tube (CFST) columns was investigated through finite element analysis (FEA) modeling. A FEA model for the seismic analysis of the column base was first established and verified with test results. The numerical model was subsequently used to study the mechanical behavior of the column base, including the typical failure modes, the load transfer mechanisms, and the interaction among components and the internal force distribution. Finally, a parametric study was carried out to investigate the effect of salient parameters on the behavior of the column base. It was found that the parameters of the outer RC component, as well as the axial load level, have significant effects on the seismic behavior of the column base, while the effects of the parameters of the CFST column and the base plate connection were moderate within the investigated parameter range. In addition, the accuracy of a simplified strength model for the column base proposed by the authors was verified with the FEA model.