Shear Behavior Of Connections With External Stiffening Ring Between Square Steel Tubular Column And Steel Beam

Square steel tubular column and steel beam frame system is widely used in highrise and super high-rise buildings because of its excellent mechanical properties,simple construction and flat appearance.As one of the three most common connection forms in the square steel tubular column and steel beam frame system,the connection with external stiffening ring occupies a place because of its unique advantages.At present,there are few studies on the shear behavior of the connection with external stiffening ring and the connection form with unequal-depth steel beams.In this paper,test method,finite element simulation and theoretical analysis are used to study the connection with external stiffening ring in the former two aspects.On the basis of consulting a large number of research literature at home and abroad,this paper summarizes the current research status of the connection with external stiffening ring,and finally determines the research direction and research means of this paper.Firstly,four full size cruciform specimens of the connection with external stiffening ring were tested under low cycle repeated load.The failure mode and the load-displacement curve of beam end were obtained.The influence of the axial compression ratio and the depth difference of the steel beams on the shear performance of the panel zone in the connection with external stiffening ring is discussed.Secondly,based on the test results,the finite element model of the conventional connection with external stiffening ring is established by using ANSYS software.The finite element parametric analysis of the conventional connection with external stiffening ring is carried out,and the influence of the width and height of the steel tube in panel zone,the thickness of external stiffening ring on the shear resistance is also discussed.The ABAQUS software is used to establish the finite element model of the connection with external stiffening ring between square steel tubular column and unequal-depth steel beams,and the main stress analysis is carried out to determine the force transfer path of the steel tube web in the panel zone.Finally,the current calculation methods of shear bearing capacity in the panel zone of the connection with external stiffening ring are summarized and compared,and their advantages and disadvantages are also described.According to the test phenomenon and finite element simulation,the bearing mechanism of the connection with external stiffening ring between the square steel tubular column and steel beam under the low cycle repeated load is defined,the shear bearing capacity calculation model and corresponding calculation formula considering the post buckling strength of the steel tube web in the panel zone of the connection are proposed.