In order to propose a design method and understand if it is possible to reduce the amount of lateral hoops and then construction cost of reinforced concrete filled steel tubular column (R-CFST) subjected to axial force, investigations were performed respectively on the ultimate strength evaluation-equation and the influence of lateral hoops on the mechanical performance of R-CFST, by means of both compression test and numerical simulation. The test variables included the patterns and spacing of lateral hoops. Two patterns with flat and spiral hoops and three different spacing of flat hoops were used. 8 R-CFSTs in 4 groups and 3 concrete filled steel tube (CFST) specimens were prepared. Analyses results on load-transfer performance, ductility, confinement and composite effect, and failure mode indicated that: before-ultimate loading performance and ultimate load-bearing capacity of the member were not relevant to the patterns of lateral hoops; differences in spacing of flat hoops would not cause significant changes in mechanical performance of member, and thus larger spacing was recommended to obtain a time and work saving construction process; spiral hoops would bring improvement to ductility and post-ultimate loading performance of the member, and thus spiral hoops were recommended when the ductility or seismic performance was the main concern. Based the experimental results, the numerical simulation method for R-CFST was investigated and a constitutive equation for its concrete core was proposed. Simulation results showed a good agreement with test results, which further confirmed the reliability of the test. At the end, investigations on prediction methods of ultimate load-bearing capacity of R-CFST were conducted. As results, the equation from US code was found to be conservative, and equations which were modified based on the Chinese code were proposed. Verification results against known experimental data indicated that the equations proposed were applicable in engineering design of R-CFST member subjected axial load.
