Experimental Study On Compression Shear Hysteretic Behavior Of Concrete Filled Square CFRP-steel Tubes

In the past engineering examples,members rarely only bear a single load such as compression,bending,shear,or torsion.They often bear the combined action of two kinds of loads,such as compression-bending,compression-shear or compression-torsion,or even more complex load combinations.Besides the static load,some structural members also bear seismic load,and the damage of the hysteretic load structure is very serious,CFRP is a kind of composite material.According to the severity of structural damage and the characteristics of CFRP,CFRP reinforcement technology is widely used in engineering.Therefore,it is necessary to study the mechanical properties of CFRP-concrete filled steel tube under hysteretic loads,it provides a basis for the subsequent research on the hysteretic behavior of members.In order to understand the compression-shear hysteretic behavior of CFRP-concrete filled steel tubular,nine concrete filled square CFRP-steel tubes compression-shear specimens were tested in this paper.The axial compression ratio and transverse carbon fiber layers were taken as the main parameters to analyze the influence of each parameter on the bearing capacity,stiffness and hysteretic performance of the specimens.The accuracy of the finite element model is verified by comparing the V-A hysteretic curve,skeleton hysteretic curve and failure mode obtained from the finite element and the test by using ABAQUS software.Then the parameter analysis is carried out to explore the influence of axial compression ratio,layers of the transverse CFRP and strength grade of concrete,yield strength and steel ratio on the hysteretic performance of the numbers.The results show that:with the increase of axial compression ratio,steel yield strength and steel ratino,the bearing capacity and stiffness of the specimen can be improved.When the number layers of the transverse CFRP and the strength grade of concrete increase,the stiffness curve shape of the specimen in elastic stage almost remain unchanged,and the bearing capacity of the specimen increases slightly slowed down,and the ductility and energy dissipation capacity can be improved;To a certain extent,the degradation of specimen strength is obvious.