| Fabricated steel structure joint is an important part of fabricated steel structure design.In recent years,Based on the concept of structural toughness,many scholars focus on the repairability of fabricated steel structure joints after earthquake,trying to control the damage of joints on the components that are easy to replace through different connection forms,so as to protect the main structural components.The research on the repairable performance of joints is of great economic and social value for earthquake resistance and post earthquake reconstruction of structures.Based on the existing research,this paper proposes a new type of connection of fabricated steel structure joint that is convenient for post-earthquake repair.The finite element analysis method is used to perform mechanical analysis on the new type of joint.The mechanical properties of the new joint under monotonic load and low cycle reciprocating load are studied.The thickness of flange,web thickness,dog bone weakening depth c and the distance between dog bone and cylinder D are analyzed By analyzing the mechanical parameters such as the hysteresis curve of the joint,the skeleton curve,the ductility coefficient and the energy consumption coefficient,the recommended value range of each parameter was given;finally,the new type of node was applied to the overall frame structure In this paper,the difference between the failure modes of the fabricated steel frame structure and the traditional steel frame structure is co MPared and analyzed.The main conclusions are as follows:(1)A new type of connection of fabricated steel structure joint which is convenient for post-earthquake repair is proposed.Using ABAQUS software to carry out mechanical analysis of Base(trial design)test pieces.The results show that the plastic hinge of the joint is located at the weakening point of the dog bone of the replaceable energy-consuming beam section,and no plastic deformation occurs in the joint domain.Seismic performance.(2)Increasing the thickness of the flange of the energy dissipation beam section can improve the bearing capacity of the joint.If the thickness of the flange is too large,it is not conducive to the formation of plastic hinges and reduces the ductility of the joint.Considering the width to thickness ratio of the flange of the energy dissipation beam section,it should be controlled within 6.2-7.8;Increasing the thickness of the flange of the energy dissipation beam section can also improve the bearing capacity of the node,but with the increase,it is not conducive to energy dissipation.Considering the height-to-thickness ratio of the web of the energy dissipation beam section should be controlled within the range of 28.6-37.2.(3)The dog bone weakening depth c is of great significance to the generation of plastic hinges.Too small a weakening depth is not conducive to yielding of the flange section,and too large is not conducive to the bearing capacity and stability of the section.The distance D between the weakened area of the dog bone and the cylinder has an important influence on the position of the plastic hinge.Through comprehensive analysis of mechanical performance indicators,it is recommended that the ratio of dog bone weakening depth c to flange width be controlled in the range of 0.18-0.24,and the ratio of dog bone weakening zone distance from cylinder surface D to beam height should be controlled in the range of 0.6-0.85.(4)The pushover analysis of fabricated steel frame and three types of welded steel frame is carried out.The results show that the plastic deformation of fabricated steel frame is concentrated in the replaceable energy consuming beam segment,while the complex plastic deformation of welded steel frame occurs in the welding position of beam column joint.The new type of repairable fabricated steel frame has good mechanical properties and repairability after earthquake. |
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