To improve the corrosion resistance of concrete-filled steel tubular column (CFST) and construction inconvenience of FRP-steel tube concrete column (FSCC)

a novel composite member is proposed

namely

FRP-interlayer-steel tube concrete column (FIST). In this paper

axial compression tests on FIST

FSCC and CFST were conducted to investigate the failure modes and the loading process. The experimental results indicated that the failure mode of FIST and FSCC was waist drum failure owing to the confinement of FRP

which is different from the shear failure mode of CFST resulting from low steel ratio. Compared with FSCC

whose resin matrix was crushed

FIST avoided this due to the existence of the interlayer. The bearing capacity and ultimate deformation of FIST increased by 35.3% and 22.5% respectively

higher than that of FSCC also owing to the interlayer. The design equation of the bearing capacity of FIST was proposed from the equations of the bearing capacity of CFST and FSCC. Calculations and test results showed good agreement.