Study On Seismic Behavior Of Wall-filled Steel Tubular Columns-external Core-bolt Joints

With the development of modern industrial technology,the construction period,cost and shape of residential buildings are difficult to meet the needs of the people.At the same time,in response to the active promotion of relevant national policies,the research group proposed WCFTS with the core of concrete-filled steel tubular columns as the core technology.(Walled Concrete Filled Steel Tube System)Green-assembled steel structure building system.Based on the characteristics of the large aspect ratio of the wall column,the out-of-plane direction does not take the initiative to bear the bending moment and the articulation method is not economical,so the semi-rigid connection method is adopted.Therefore,this paper combines the research results at home and abroad to propose a highly adaptable wall-type CFST column-out-of-plane through-bolt joint.In this paper,the combination of experimental research and finite element analysis is used to study the seismic behavior of wall-type CFST column-out-of-plane through-bolt joints.Specifically complete the following work:(1)The pseudo-static test of four full-length specimens of CFST-external throughbolt joints is carried out,and the hysteretic behavior,stiffness degradation,ductility and energy dissipation of the specimens are studied.And the destruction mode.The test results show that the plastic end of the beam end has a certain plasticity development on the back side of the end plate,which is a typical strong joint failure mode,which reflects the good energy dissipation and ductility of the wall-type CFST column-out-of-plane piercing joint.(2)The ABAQUS finite element software is used to simulate the mechanical behavior of the joint under low-cycle reciprocating load,and the failure mode,force performance and seismic performance of the joint are further analyzed.The results show that the load-displacement curve and failure mode of the finite element calculation are basically consistent with the experimental results,which verifies the correctness and authenticity of the finite element analysis.(3)The parameters expansion analysis of the components was carried out by using ABAQUS finite element software.The effects of axial compression ratio,end plate thickness,bolt diameter,wall thickness of joint zone and thickness of joint zone separator on the seismic behavior of the specimen were studied.The analysis results show that the control axial compression ratio can effectively control the ductility and bearing capacity of the joint specimen;the end plate thickness,bolt diameter,joint zone steel pipe and joint zone partition can control the node failure mode,and the end plate thickness and bolt diameter can be effectively controlled.The gap between the end plate and the column wall prevents the connection from being broken;the steel tube and the partition plate in the node area can effectively control the deformation of the node domain,thereby preventing the weak node from being destroyed.(4)According to the failure mode and force transmission mechanism of the node,the construction suggestions of each component of the node are proposed,which can provide reference for the production and construction of the node.