Experiment study of reinforced concrete filled steel tubular columns subjected to axial compression

The mechanical properties of concrete-filled steel tube can be improved with longitudinal reinforcement. With three main parameters of longitudinal reinforcement strength, reinforcement ratio and stirrup ratio, 13 short concrete-filled steel tubular column were designed and tested under axial compression. Each specimen's failure characteristics, ultimate bearing capacity and load-displacement curve were analyzed and the impacts of various parameters on the deformation and bearing capacity of concrete filled steel tube column were studied. The results indicate that: comparing with the common concreted-filled steel tube, the concreted-filled steel tubular column with inner rebar has different failure mode, stronger bearing capacity and better post-yield ductility. Reducing stirrup spacing can delay the development of local buckling. Normal reinforcement yields ahead of steel tube. The numerical analysis by finite element software ABAQUS was presented, and its results were in good agreement with test results.