| In recent years,with the implementation of the national green development strategy,light steel structure has developed rapidly.Light steel structures mostly use open section steel,while closed section steel joints are not easy to connect.Most of the existing closed section steel joints are welded joints,so it is difficult to realize full bolt connection.Based on this,this paper proposes a new type of square steel tube beam-to-column all-bolt sleeve joint,which effectively solves the problem of square steel tube beam-to-column all-bolt connection.The joint structure is simple and the cost is low,which improves the construction efficiency of light steel structure and enriches the assembled light steel structure system.The form of square steel tube beam-to-column connection joints has good development prospects in low-rise buildings.In this paper,the seismic performance of the new square steel tube beam-to-column all-bolt sleeve joints is studied by means of experimental research and numerical simulation.The research contents and main research results are as follows :(1)Quasi-static tests of four new square steel tube beam-to-column all-bolt sleeve joints were carried out to study the seismic performance of the new square steel tube beam-to-column all-bolt sleeve joints.The failure modes of different joints are discussed.The results show that the failure modes of the joints are divided into the weld failure of the end plate of the core area and the welding part of the square steel tube beam,and the bolt pull-out failure of the core area.Observing the failure phenomenon of the new square steel tube beam-to-column all-bolt sleeve joint,it can be seen that the thickness of the end plate,the thickness of the outer plate of the beam and the weld connection between the end plate and the square steel tube beam are important factors affecting the failure mode of this kind of joint.(2)The quasi-static test results of the new square steel tube beam-to-column all-bolt sleeve joints were compared and analyzed.The effects of different structural forms of the joints on stiffness degradation,strength degradation and displacement ductility were studied.The results show that the bearing capacity and stiffness of the cantilever beam joint with inner sleeve are higher than those of the end plate joint with inner sleeve.The setting of stiffeners in the end plate joints effectively inhibits the deformation of the joints and alleviates the weld damage,which is conducive to improving the bearing capacity of the joints.The new square steel tube beam-to-column all-bolt sleeve joints have high bearing capacity,good ductility and energy dissipation capacity.According to the relevant provisions of the European code EC3 on rigid,hinged and semi-rigid connections,the new type of square steel tube beam-column all-bolt sleeve joints are semi-rigid joints.(3)A refined finite element model that can accurately simulate the new square steel tube beam-to-column all-bolt sleeve joints is established.The refined model can consider the complex contact relationship between various components,and consider the influence of parameters such as the thickness of the end plate in the core area of the joint,the beam-to-column linear stiffness ratio,the thickness of the square steel tube beam wall,the thickness of the stiffener end plate,and the thickness of the inner sleeve of the beam on the seismic performance of the new square steel tube beam-to-column all-bolt sleeve joints.The results show that the numerical simulation results are in good agreement with the experimental results,and the end plate thickness of the end plate joint and the end plate stiffened joint has a great influence on the seismic performance of the joint.With the increase of the length of the beam,the linear stiffness ratio of the beam to the column decreases,and the end plate at the joint is prone to large bending deformation and stress concentration. |
PDF Full Text Request