Experimental Study On Hysteretic Behavior Of Circular Concrete Filled CFRP-steel Tubes Under Compression And Torsion

Concrete-filled steel tube is a kind of combined structure which formed by filling concrete into steel tubes.This structure make full use of the compressive properties of concrete and the tensile properties of steel tubes.So it's widely used in civil engineering field.But it's prone to corrosion by chemical.Therefore,reinforcement and repairment are the two key research direction of concrete-filled steel tube.Carbon fiber reinforced plastic(CFRP for short)are commonly used due to their excellent properties.The combination of CFRP and concrete-filled steel tube avoids the shortage of the concrete-filled steel tube,and improves the bearing capacity of the structure.The research of static behavior on concrete filled CFRP-steel tube has gradually matured,but there hysteretic behavior are not comprehensive.This paper includes experimental study and finite element simulation on the compression-torsion hysteretic behavior of concrete filled CFRP-steel tube.Design and produce eight concrete filled CFRP-steel tube specimens and one concrete filled steel tube specimen.Introduce the manufacturing process and loading scheme.The test results show that CFRP and steel tube can work together before CFRP break;specimens have good ductility and energy consumption;transverse CFRP layers has little effect on the strength degradation,stiffness,stiffness degradation and energy dissipation of specimens.As the axial compression ratio increases,the initial stage stiffness of specimens increases,and the energy dissipation coefficient increases to the later loading stage.Establish the model of compression-torsion hysteretic behavior circular concrete-filled CFRP-steel tube by finite element analysis software ABAQUS.Comparison between test results and simulation results are in good agreement.Parameters analysis results show that the increase of concrete strength and lateral CFRP layers improves bearing capacity slightly.Increases the axial compression ratio improves the bearing capacity.The skeleton curves without falling section,and the member has good ductility..