Experimental Study On Hysteretic Behavior Of Square Concrete Filled CFRP-steel Tubes Under Flexural And Shear

Concrete-filled steel tube(CFST)makes full use of the tensile strength of steel and the high compressive strength of concrete,thus improving the performance of materials.Its main characteristics are strong bearing capacity,good ductility and seismic performance,etc.,so it is widely used in modern buildings.However,the concrete filled steel tube structure itself also has inevitable shortcomings,such as poor corrosion resistance and prone to steel tube external buckling,These shortcomings will have a negative impact on the structural safety of buildings.According to the research,CFRP-concrete-filled steel tube structure not only has its advantages compared with concrete-filled steel tube structure,but also has the characteristics of high tensile strength,durability and corrosion resistance.Moreover,the poisson ratio and elastic modulus of CFRP and steel tube are close to each other,which makes up for the shortcomings of concrete-filled steel tube structure.The nine flexural-shear specimens as research objects are taken in this paper to study the flexural-shear hysteresis properties of Concrete filled CFRP-steel tube(CFST),and the comparison was made by ABAQUS finite element calculation.The test results show that:(1)With the increase of the number of transverse CFRP layers,the bearing capacity of specimens increases slightly;With the increase of shear span ratio,the bearing capacity of specimens decreases;CFRP and steel tube can work together;The increase of transverse CFRP layer number and shear span ratio have no obvious effect on the energy dissipation of CFRP-CFST specimens subjected to flexural shear hysteresis.(2)The strength of concrete has little effect on the shape and stiffness of the hysteretic skeleton curve,but the strength of steel has great effect on the bearing capacity,and the bearing capacity increases with the increase of steel strength.(3)The finite element analysis software ABAQUS was used to establish the flexuralshear hysteretic behavior model of Concrete filled CFRP-steel tube(CFST),and the test results are in good agreement with the simulation results.