| In the steel frame structure system,the way of welding joints for H-beams and columns is still very extensive.However,as the earthquake continues to occur,many problems are also exposed.Especially for the characteristics of the steel frame structure itself,the corner frame is highly susceptible to instability and damage to the overall structure.Through a large number of earthquake damage experience,it is shown that the damage of the framework is mostly caused by the destruction of the nodes.As the most stressed area in the steel frame beam-column joint,the node domain is also the main energy-consuming area in the steel frame beam-column system.Once the damage occurs,the damage to the whole frame structure is extremely high.Through the experiments of a large number of related nodes by relevant scholars at home and abroad,it is proved that the joint domain of the steel frame beam-column joint mainly undergoes shear deformation.If the node domain is too thin,the deformation will be large,and shear damage will occur.If the node domain is too thick,the overall structure will be insufficiently deformed,resulting in insufficient ductility and energy consumption.This paper focuses on the weak node domain in existing corner steel frame nodes,and improves the measures of reinforcing the nodes with diagonal ribs.The aim is to make the nodes have certain deformation and energy dissipation capacity,and also have certain strength and stiffness to form a strong node failure mechanism.To ensure that the node domain does not break before the beam and column members in the event of an earthquake.In this paper,the combination of finite element simulation and experimental analysis is used to discuss the influence of the reinforcement rib parameters on the seismic performance of the beam-column joints and the damage mechanism.The main contents are as follows:Firstly,the research status of existing traditional nodes at home and abroad and the necessity of reinforcement are obtained,and the current situation and shortcomings of domestic scholars on the mechanism of the stress field in the beam-column nodes are analyzed.Starting from the domestic seismic design principle of steel frame joints,the main parameters and evaluation criteria of seismic resistance of joints are introduced.The design formulas for earthquake resistance of steel structures and the nonlinear theory of finite element steel joints are summarized.Secondly,using the finite element analysis software,the influence of the reinforcement ribs connected with the surrounding boundary plates on the seismic performance of the joints is analyzed separately.Then,from the reinforcement joints disconnected from the diagonal ribs and the surrounding boundary plates,the thickness of the reinforcement ribs is separately Eight nonlinear finite element models are designed for the two parameters of length,and the stress distribution,failure mechanism,hysteresis curve,skeleton curve,energy dissipation capacity and plastic hinge external displacement of the center of the model node are analyzed.The results show that the traditional diagonal rib reinforcement measures increase the bearing capacity of the joints,but it is not conducive to seismic energy consumption.The new diagonal rib reinforcement measures can effectively improve the bearing capacity and energy dissipation capacity of the joints,improve the failure modes of the joints and improve the deformation The change of rib thickness is particularly obvious,and it is an effective and reasonable reinforcement measure;Finally,the quasi-static test of the traditional welded joints and the new optimal parameters of the diagonal rib reinforcement is carried out.The results show that the new diagonal rib reinforcement node has higher bearing capacity and stiffness than the traditional node,and the stress level of the node domain is always lower than the traditional welding node.In terms of seismic energy consumption,the seismic performance of the new diagonal rib reinforcement node is better than that of the traditional welded joint and the plastic hinge can be moved outward,thus achieving the seismic concept of “strong joint”.In addition,the experimental and finite element results data were compared and analyzed to verify the accuracy and reliability of the finite element model.The paper has 63 pictures,11 tables,and 64 references. |
