Study On Hysteretic Behavior Of Replaceable Flange Weakening End Plate Connection Node

It has become an important development trend that the function of the structure can be restored and the damage element can be replaced after the earthquake.On the basis of the existing research results of steel structure beam column joints,an end plate connection node with replaceable flange with long slot holes was proposed.In order to study the failure mode of the joint under cyclic loading and the influence of weakening parameters on the hysteretic performance of the joint,the finite element software ABAQUS is used to simulate and analyze the joint with variable parameters,and some design suggestions are given.On the basis of verifying the validity of finite element software ABAQUS,the mechanical properties of ordinary end plate joint and replaceable flange long slot weakening end plate joint under monotonic and cyclic loading are compared and analyzed.The results show that compared with the ordinary end plate joint,the weakened joint can realize the plastic hinge moving out more effectively,protect the butt weld of the beam column joint better,and avoid the brittle failure prematurely;although the bearing capacity of the weakened joint is reduced to some extent,the ductility of the joint is improved,and its hysteretic performance is better.Four variable parameter series are designed,including the diameter of the long slot hole,the length of the long slot hole,the distance from the center of the long slot hole to the edge of the beam,and the thickness of the end plate.The influence of various parameter on the bearing capacity,failure mode,ductility,energy consumption capacity,stiffness and strength degradation of the weakened joint is explored,and the reasonable value range of each parameter is given.It is found that the hysteretic performance of the joint is more sensitive to the change of the hole diameter of the long slot.The value of the long slotted hole diameter should consider the interaction between the bearing capacity and ductility of the joint,so as to optimize the joint performance.The length of the long slot has little effect on the performance of the joint,but in a certain range,properly increasing the length of the long slot can make the joint have good ductility.The distance between the center of the long slot hole and the edge of the beam has a certain influence on the ultimate bearing capacity and strength degradation rule of the RFB joint.When the specimen is weakened,the distance between the center of thelong slot hole and the edge of the beam should not be too large.In order to avoid the end plate connection becoming a weak link of the beam-column connection node,the end plate thickness should not be too small.However,when the thickness of the end plate is too large,the performance of the joint is not greatly improved by the addition of the end plate stiffener.In order to save steel,the end plate stiffener may not be added at this time.