Research On Seismic Performance Of New Friction "Plastic Hinge" Structure Of Steel Frame

Earthquakes often lead to a series of earthquake disasters,resulting in building collapse damage and casualties and other loss of life and property.In modern buildings,the steel structure building is more and more widely used for its good application advantages.Many engineering practices and earthquake disasters show that plastic hinge is easily formed at the beam-column joint,which plays an important role in the steel structure building structure,and can effectively absorb and dissipate energy,so as to make the building structure meet the seismic fortification requirements of large earthquake not falling down,and middle earthquake can be repaired.It was found in the research of traditional steel structure joint that the rigidity of traditional beam-column joint leads to a large number of brittle failure of structural members,which leads to the fracture or collapse of the steel frame of the building and causes great economic losses.With the research development of steel frame new ductility node,researchers put forward many good seismic performance of beam-column connection ductility of node type,make the steel frame structure of the plastic hinge overseas.It was found that although the existing ductile joints have good ductility and other mechanical properties,they could not prevent the building from being damaged and difficult to be repaired during a major earthquake,thus becoming “standing ruins”.Based on existing research on ductility joints,a new type of friction “plastic hinge” structure was proposed in this paper to achieve the goal of non-maintenance or quick repair of steel structure under earthquake action.Firstly,this paper presented the conceptual design and seismic mechanism of the friction “plastic hinge”,and designed a new type of T-beam and column structure joints of friction "plastic hinge" structure.Its working principle and seismic performance were deduced theoretically,and the recommended parameters for its structural design were given.Secondly,this paper introduced the experimental study on the mechanical properties of the new friction “plastic hinge” structure,and analyzed the influence of the contact slip surfaces on the bearing capacity of the beam end under the action of different friction materials and the connection plate under the action of different bolts.The characteristics of load-displacement curves and their influencing factors under different test model conditions were investigated.Through the finite element software ABAQUS,the finite element model was established and its mechanical properties were numerically analyzed.The mechanical properties of its finite element simulation results,theoretical analysis and test results were compared and analyzed.Thirdly,based on the existing research theories and structural types of the improved joints,the mechanical properties of the three improved steel frame joints were compared and analyzed.The mechanical properties of the common(base)type joint,the dog-bone(reduced beam section)type joint,the Opening in beam web joint and the new type of friction “plastic hinge” structure were analyzed by the finite element software ABAQUS.The seismic performance of different types of steel frame joints under low cyclic cyclic loading,such as hysteretic per formance,failure mode,ultimate bearing capacity,joint ductility,stress distribution and plastic turning Angle,was investigated,which provided the feasibility basis for further research and application of the friction “plastic hinge” structure.The results showed that the mechanical properties of all types of joints are affected by the setting parameters,and the dog-bone joints showed better seismic performance.The bearing capacity of friction “plastic hinge” structure parameters could be set up by bolt spacing and the characteristics of shear bolt to adjust the size,the sliding friction spinning stage showed good ductility performance.Finally,according to the research on the forming characteristics of friction “plastic hinge” and its energy dissipation mechanism,SAP2000 analysis software was used to carry out the nonlinear static procedure of a 6-storey steel frame structure,so as to explore the characteristics of the structural properties of the frame analysis model changing with the analysis conditions.This paper introduced the basic principle of static elastic-plastic analysis of frame structure,established the default hinge fitting steel frame structure analysis model based on friction “plastic hinge” and Pushover analysis,and explored the formation and development mechanism of structural component “plastic hinge” and the motion state of the overall frame structure under load by Pushover analysis method.Through the elastic design review of steel frame structure under the action of frequent earthquakes and the structural failure mechanism analysis under the action of rare earthquakes,the adjustment of the weak area of the structure was carried out and the seismic performance of the frame structure was evaluated to verify whether the steel frame structure meet the seismic design requirements of displacement and inter-storey displacement angle and the mechanical characteristics of “strong column and weak beam” and “strong shear and weak bending” under the action of earthquakes.