摘要

In order to study the seismic performance of the elliptical concrete-filled steel tubular (ECFST) member, pseudo-static tests of ECFST columns under horizontal low-cyclic load and axial force were carried out. The effects of axial compression ratio and concrete strength on the lateral bearing capacity, stiffness, ductility and energy dissipation of the columns were studied, and the major failure modes and mechanical mechanism of ECFST columns under horizontal low cyclic load are revealed. Moreover, based on the elliptical section feature and code programing, a finite element model of the cyclically-loaded ECFST column was established using the OpenSees software. The accuracy and feasibility of the FE model were verified by comparing the predicted data with the test results. Then, the feature of seismic behavior of the ECFST column relative to the normal CFST columns was discussed. After that, the effect laws of various material and geometric parameters on the seismic behavior of the ECFST column was systematically concluded. The results show that the ECFST columns have better seismic performance than those of the normal CFST columns in terms of higher strength, stiffness and energy dissipation. Under horizontal low cyclic loads, the failure modes of ECFST columns mainly include local buckling and tearing of the steel tube, and concrete crushing at the bottom end of the column. ? 2023 Editorial Office of China Civil Engineering Journal.