Concrete filled steel tube (CFST) columns subjected to concentrically partial compression

This paper studies the behaviour of thin-walled concrete filled steel tube (CFST) column subjected to concentrically partial compression. A series of tests was carried out to investigate the effects of sectional type, length-to-diameter (width) ratio, partial compression area ratio and top endplate thickness on the behaviour and bearing capacity of partially loaded CFST column. Twenty-six CFST specimens were tested, and the bearing capacity, load versus deformation relation and failure mode of the specimens were obtained. It was shown that the CFST columns under concentrically partial compression generally had reasonable bearing capacity and ductility. A finite element analysis (FEA) model was developed for simulating the behaviour of CFST column subjected to concentrically partial compression, and a comparison of the performances predicted using this model showed generally good agreement with the test results. The FEA model was then used for the mechanism analysis of CFST column subjected to concentrically partial compression. Finally, a simplified model that could be used to predict the bearing capacity of the composite column under concentrically partial compression was proposed.