Study On Application Of Self-resetting Swing Rigid Frame In Frame Structures

It has been found that the concrete frame structure is prone to layer yield phenomenon under the action of earthquake.The failure of column is earlier than that of beam,which is contrary to the failure mechanism of "strong column and weak beam" which is expected in the seismic design of the structure,and is not conducive to the earthquake resistance of the structure.Moreover,the failure of columns in advance will bring more residual deformation to the structure,which will increase the difficulty of repairing the structure in the later period,and the cost of repairing the structure after the earthquake will also increase greatly.Therefore,it is an economical and effective earthquake-resistant method to do a good job of earthquake-resistant structure before earthquake and prevent the yielding mechanism of structure under earthquake action.The addition of rocking wall to concrete frame structure is a new type of structure at present.Anti-seismic reinforcement method.Under the action of earthquake,the rocking wall and the concrete frame structure are allowed to rock and work together,so that the deformation of the structure can be effectively reduced,and the damage mechanism of the concrete frame structure can be controlled.However,the anti-seismic method has a great demand on the swinging wall,and the swinging wall is required to have certain anti-lateral rigidity to achieve the purpose of controlling the deformation of the control structure and improving the yield mechanism of the structure.However,the swing wall with large anti-lateral stiffness tends to be heavy and difficult to install,can increase the earthquake action of the structure under the action of the earthquake,the volume of the swinging wall is large,the external part of the frame structure is easy to block the sunlight,and the lighting effect of the structure is influenced and the like Title In view of the above problems,a new self-reset rocking rigid frame reinforcement method outside the structure is proposed in this paper,referring to the two seismic design ideas of appended substructure and recoverable structure outside the structure.The H-section steel is used to make a rigid frame and relax the constraint between the rigid frame and the foundation,allowing the structure to swing in the plane to replace the rocking wall in order to meet the lateral stiffness and rocking requirements of the original structure for the additional substructure.In addition,the post-tensioned prestressed steel strands are introduced into the rocking rigid frame to provide the selfreset ability for the structure,and a frame-self-reset rocking rigid frame structure system is formed.Appending to the concrete frame structure for the purpose of study The influence of the self-reset rocking rigid frame on the seismic performance of the original structure is studied in this paper with a 5-story existing concrete frame structure as the research object.The finite element models of concrete frame structure and frameself-reset rocking rigid frame structure are established by using finite element software Sap2000.The modal analysis,Pushover analysis and elastic-plastic dynamic time history analysis of the two structures are carried out respectively.The finite element calculation results of two kinds of structural systems are compared and studied.The research contents and conclusions of this paper are as follows:(1)This paper introduces the composition and working principle of the self-reset rocking rigid frame.Based on the stiffness requirement of the concrete frame structure,the self-reset rocking rigid frame is designed,and the self-reset rocking rigid frame is formed by connecting the rigid chain rod.The finite element software Sap2000 is used to model the concrete frame structure and the frame-self-reset rocking rigid frame respectively,and the modal analysis is carried out.The results show that the addition of self-reset rocking rigid frame will not significantly affect the natural period of the structure and increase the stiffness of the original structure,nor will the seismic action of the structure be significantly increased.(2)Based on the capacity spectrum method,the finite element model of concrete frame structure and self-reset rocking rigid frame structure is analyzed by Pushover using reverse triangular lateral loading mode,and the base shear-vertex displacement curves of two kinds of structures are obtained.The results of performance points,structural displacement response and plastic hinge distribution under different earthquake intensities are given.The seismic performance of structures before and after additional self-reset rocking rigid frames is compared and analyzed.The results show that the addition of self-reset rocking rigid frame can effectively improve the lateral bearing capacity,energy dissipation capacity and ductility of the concrete frame structure,and can effectively avoid the concentration of inter-story deformation and control the story of the frame structure.According to the yield mechanism,the deformation of each floor tends to be uniform,forming the whole deformation mode,giving full play to the overall anti-seismic capacity of the structure and enhancing the energy dissipation of the structure at the same time.(3)Metal dampers are added to the frame-self-reset rocking rigid frame structure in order to increase the energy dissipation and protect the structural members.According to the seismic code of our country,two natural waves and one artificial wave are selected to analyze the dynamic elastic-plastic time history of the three models respectively.The natural period,maximum displacement and inter-layer displacement angle,acceleration response and energy distribution of three kinds of structures under earthquake action are obtained.The results show that when metal damper is added to the frame-self-reset rocking rigid frame,the plastic deformation of the metal damper dissipates the seismic energy,reduces the displacement and acceleration response of the structure,and reduces the input energy of the structure during the earthquake.Quantity,plays a protective role on the structure.