Study On Mechanical Properties Of Prefabricated Inner Sleeve End-plate Beam-column Joint

In recent years,due to the merits of good stability,convenient construction and decoration,the rectangular steel pipe column has been more and more widely used.Compared with the steel column and H steel column,the two principal axes are the same section stiffness,inertia moment of the cross section is relatively large and capacity is close to and especially in the steel-concrete composite structure.The concrete filled steel tubular column can make full use of the advantages of steel and concrete and fire resistant performance is good,the structure bearing capacity is high,and its application scope is wider.Rectangular steel tube column and H type steel beam usually use the welding method,but it is difficult to ensure and the weld quality is easy to break.Therefore,the assembly connection form has been paid more and more attention.According to the current domestic norms and relevant norms of the united states,the design process of the prefabricated inner sleeve end-plate beam-column joint is presented,which provides reference for the engineering design.According to mechanical properties of prefabricated inner sleeve end-plate beam-column joint,Mechanical properties of joints under the action of unidirectional static loading are analyzed by using structure finite element analysis software ANSYS.Through the changing the bolt combination form,the inner sleeve thickness and the gap between the rectangular steel tube column and the inner sleeve wall thickness,and study the influence of three factors on the mechanical properties of joints under the static loading.The study found that bolt combinations exist only influence on the distribution of the stress on the wall of the column,and has a little influence on the bearing capacity of the joints and stiffness.The column wall stress decreases and the beam flange plastic development fully with the increase of inner sleeve thickness,it can increase the rigidity of joints effectively,but the thickness of the inner sleeve should not be too large;the gap between the rectangular steel tube column and the inner sleeve wall has great influence on the joint stiffness,the stiffness was significantly reduced when gap is too large.In order to ensure the connection joints stiffness,the gap should be minimized in the process of manufacture.Based on the analysis of the static under uniaxial loading,the research of seismic performance of the joint was conducted through applying cyclic loading on beam end.Through changing the bolt combination form and the inner sleeve thickness,the research of the variation of seismic behavior of the joints was conducted through applying cyclic loading on beam end.The results show that: in the composite bolts connection,high-strength split bolt connection and high strength bolt connection,the mechanical property of high strength bolt connection form is optimal.The hysteretic performance,yield capacity,ultimate bearing capacity is higher than the other two types of combination of connections.With the increase of the inner sleeve,the thickness of the hysteretic behavior of the joints,yield capacity,ultimate bearing capacity and energy dissipation capacity were increased.It is suggested that the seismic behavior of the joint was change effectively with the increase of the inner sleeve.