| In order to solve the problem of poor seismic performance of the traditional weak-axis connection on I-section columns,a new box-shaped panel zone extended end-plate weak axis connection suitable for I-section connection was put forward.The mechanical properties under low cyclic loading of four different panel zone models of the end-plate connection were compared and analyzed by finite element software ABAQUS.By studying the failure modes of node,the moment-rotation curve,the note stiffness degradation and the energy dissipation capacity,it is shown that the extended end plate connection nodes of the box-shaped panel zone have better seismic performance.Based on this connection,the finite element analysis method of variable parameters was used to study the influences of seismic performance of the new connection,parameters including the skin plate,bolt type,bolt grade,bolt number and arrangement,end plate,and stiffeners.based on the results of finite element simulation analysis,the main conclusions are as follows:1.Compared to other types of end plate connection nodes for weak-axis,the box-shaped panel zone extended end-plate weak axis connection can provide higher strength and rigidity,prevent the panel zone from undergoing large plastic deformation,it has obvious "strong node domain" feature.The connection has better seismic performance under cyclic loading.2.The height change of the skin plate has little effect on the failure mode of the joint and the mechanical properties.According to the structure,the height of the skin plate and the end plate can be the same.Considering the function of the pressed steel plate assembly floor,it is recommended that the height of the skin plate protrudes up and down from the beam flange at least 150 mm.3.With the increase of the thickness of the end plate or skin plate,the failure mode of the joint is mainly changed from the buckling failure of the end plate or skin plate to the failure of the plastic hinge at the beam.Thus,the values ranges of end plate and skin plate are given.4.Increasing the number or diameter of bolts can improve the stiffness of the joint and the energy dissipation capacity,but the plastic rotation capacity of the joints is reduced.5.Increasing the bolt marginal and center distance has little effect on the failure modes and the mechanical properties of the joints.However,the increase in the distance between the bolts can effectively reduce the plastic deformation of the skin plate of the bolt holes.Considering the protection of the node domain,The distance between bolts can be the larger value based on the bolt hole spacing requirements,while the bolt margin from the perspective of saving steel can just meet the minimum requirements of the bolt spacing.6.Different types of stiffener can all play the role of making the plastic hinge on the beam move outwards,reducing the plastic deformation on the skin plate and weld seam of the node domain,and improving the initial rotation stiffness and bearing capacity of the joint.The use of triangular stiffeners or trapezoidal stiffeners has little effect on the mechanical properties of the joint,but the change in the length ratio of the stiffeners has a significant effect on the performance of the note.When the ratio of the length to length of stiffener is approximately 2:1,the overall performance of the node connection is good,and it is recommended.7.According to stiffness classification criteria of European EC3 specification,for the box-shaped panel zone extended end-plate connection studied in this paper,the node with buckling failure of the end plate or skin plate is generally semi-rigid,and the node with plastic hinge destruction of the beam flanges is classified as rigid node. |
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