Research on behavior of RPC filled circular steel tube column subjected to axial compression

Based on the experimental study of 22 reactive powder concrete(RPC) filled circular steel tube columns subjected to axial compression, this paper analyses the load versus displacement curves, the failure patterns and the all course of work. The results show that the elastic region of the load versus strain curves is about 90%-95% of the whole, specimen with low confinement factor () exhibits a rapid softening process in the post-peak region, and a brittle shear failure, while specimen with high confinement factor exhibits a gradual softening process in the post-peak region, and causes serious bulge in all sections and significant buckling on the top and bottom of the specimen. Based on analyzing the test results of 40 specimens at home, this paper also presents the calculation formula of the theory-character parameters (peak stress, peak strain and plateau stress) for RPC filled circular steel tube and the equation for complete stress-strain curve. Calculation methods of concrete filled circular steel tube in different codes are checked and contrasted, finally the calculation formula for ultimate loading capacity of RPC filled circular steel tube columns under axial compression is proposed.