Study On Seismic Behavior Of Beam Column Semi-rigid Joints With Three-side Connector

In a steel frame structure system,semi-rigid joints can avoid the brittle failure of welded steel joints due to the stress concentration of the welding process.At present,semi-rigid joints have not been widely used because of complicated connection,difficult construction and complex stress,which need to be solved.In this paper,the beam column semi-rigid joints with three-side connector with a simple connection form and convenient installation is proposed,and its seismic performance is studied.The following are the main research contents and conclusions:(1)The existing semi-rigid joint experiments are introduced,and the experiments results are verified by ABAQUS.The modeling and analysis methods of the finite element model are given.Furthermore,according to the current code,the geometric dimensions of the components of the beam column semi-rigid joints with three-side connector calculated and analyzed in this paper are determined.On this basis,the finite element model of the beam column semi-rigid joints with three-side connector is established.(2)Parametric analysis of the beam column semi-rigid joints with three-side connector is carried out.Seven factors that affect the moment-rotation relationship curve of the joint,including the Thickness of Vertical Leg,Thickness of Horizontal Leg,Thickness of Rib Stiffener,Strength Grade of Steel,High-Strength Bolt Diameter,Coefficient of Friction,Axial Pressure Ratio,are selected for parametric analysis,and the influence of various parameters on the seismic performance of joints is studied.The results show that the Thickness of Vertical Leg,Strength Grade of Steel and Axial Pressure Ratio have a greater impact on the bending capacity of the joint.The Thickness of Vertical Leg,High-Strength Bolt Diameter and Axial Pressure Ratio have a great influence on the rotational stiffness of the joint.The Thickness of Vertical Leg,Thickness of Rib Stiffener,Coefficient of Friction and Axial Pressure Ratio have great influence on the hysteretic energy dissipation capacity of the joint.(3)Based on the parametric analysis of the finite element model,a modified quadrilinear model based on the European code EC3 model is used to describe the moment-rotation curve relationship of the beam column semi-rigid joints with threeside connector.The parameters in the mathematical model are determined.The sensitivity analysis method is used to analyze the bending capacity and initial rotational stiffness of the joint.The results show that the Thickness of Vertical Leg has the largest impact on the bending capacity of the joint,and the High-Strength Bolt Diameter has the largest impact on the initial rotational stiffness of the joint.The calculation formulas of flexural capacity and initial rotational stiffness based on sensitivity analysis are given,and the accuracy of the mathematical model is verified.(4)According to the requirements of current codes and economy,the structural design method of the beam column semi-rigid joints with three-side connector is presented.According to the possible failure mode of the beam column semi-rigid joints with three-side connector,the theoretical analysis and calculation of the bearing capacity of each component are carried out to enrich the design theory of semi-rigid connection,which has improved the calculation method of semi-rigid connection joints.