Numerical Analysis Of Seismic Behavior Of T-shaped CFST Column Steel Beam Joint With Side Plate Connection

Compared with the circular and rectangular concrete columns,the special-shaped concrete-filled steel tubular columns can avoid the edges of the columns protruding from the wall,which can achieve the purpose of effective utilization of the indoor area.However,at present,there are few joint types of special-shaped CFST column steel beam composite structure,which is difficult to meet the needs of many practical projects.Therefore,in view of the problems such as the few types of special-shaped CFST column steel beam joints,the unsystematic analysis of the mechanical properties of the joints and the lack of in-depth study on the calculation method of the bearing capacity of the joints,this paper analyzes the seismic performance of a kind of T-shaped CFST column steel beam joint with side plate connection by means of quasi-static test,finite element analysis and numerical analysis.Firstly,the refined joint models which are consistent with the size of the test members are established by using the finite element analysis software ABAQUS and their seismic performances are analyzed;secondly,the parameter expansion analysis of the joint model is carried out;finally,the calculation suggestions of the bearing capacity of the joint model are put forward.The specific research contents can be shown as follows.(1)ABAQUS is used to build 7 joint models which are consistent with the size of test members,and the finite element analysis is carried out.Through the analysis,the failure modes of the joint models and the test members are compared,and the hysteretic curve and skeleton curve of the two are compared.Finally,the ductility,energy dissipation capacity and stiffness degradation of the joint model are analyzed.The results show that the failure position of the test component is the flange of the I-beam connected with the beam column due to the existence of the side plate,the failure mode is the hinge failure of the beam,the seismic performance of the joint model is better,and the test results are in good agreement with the calculation results of the joint models.(2)Based on the analysis of the expansion parameters of the refined finite element model of the joint,the parameters such as axial compression ratio,steel strength,core concrete strength,different loading methods and vertical loading position are considered.Through the study of the hysteretic curve and skeleton curve of the joint model,the seismic resistance performance of the joint is analyzed,and suggestions for the design of such joint model are put forward.The results show that: ultimate bearing capacity and energy dissipation capacity of the models decrease when axial compression ratio increases;when the core concrete strength changes,the seismic performance of the joint models basically do not change;with the increase of the steel strength,the ultimate bearing capacity of the whole member does not change much;when the beam end loading is adopted in the joint model,the failure part of the model may be located at the web of the steel beam;when the position of the constant vertical load at the column end changes,the hysteresis loop obtained by the joint model simulation may appear asymmetric phenomenon.(3)According to the test results and the finite element simulation of joint models,when meeting the condition that the plastic hinge occurs at the beam end,the bearing capacity of the joint can be simplified as the bearing capacity of the I-steel beam end of the concrete filled steel tubular beam column connection,and calculated in combination with the relevant specifications.