Analysis And Research On Seismic Behavior Of Frame-self-reset Rocking Wall System

In order to avoid the occurrence of earthquake hazards,China revised the "Code for Seismic Design of Buildings" in 2016 to improve the seismic fortification intensity in some areas,therefore,the original buildings in such areas do not meet the existing seismic design specifications,and they need to be seismically strengthened.After investigation and study on the damage of buildings after many earthquakes,it is found that the destory of the frame structure is mainly caused by the plastic hinge at the column end of the building to form a local weak layer,which causes the interlayer deformation to be too large.Previous studies have shown that in the event of earthquakes,the rocking wall structure system can make the displacement response between the layers tend to be uniform,effectively avoiding the occurrence of layer yield failure and improving the seismic performance of the structure.However,the rocking wall structure system will still have large residual deformation after experiencing the earthquake.Therefore,a frame-self-reset rocking wall structure system and a frame-self-reset energy-consuming rocking wall structure system are proposed in this paper,which can not only meet the requirements of seismic design code,but also effectively reduce the residual deformation of the structure after earthquake.In this paper,SAP2000 finite element analysis software is used to analyze the seismic performance of frame rocking wall structure,frame-self-reset rocking wall system and frame-self-reset energy-consuming rocking wall system.The specific research results are as follows:(1)Nonlinear static analysis and nonlinear dynamic time history analysis are carried out for the original frame structure,frame-rocking wall structure and frame-self-reset rocking wall structure.By comparing the performance indexes of the structure,the self-resetting ability and seismic performance of the three structures are analyzed.The results show that the self-resetting ability and seismic performance of the original frame structure can be effectively improved by adding rocking walls to the frame structure;The addition of prestressed tendons on the frame-rocking wall structure can further improve the seismic performance of the structure and significantly reduce the residual deformation of the structure,so that the structure can be quickly restored by a little post-earthquake repair.(2)By changing the spacing of prestressing tendons in the rocking wall,a comparative model of three different spacing of prestressing tendons is established.Through the calculation and analysis,the influence of the spacing of the prestressed tendons in the rocking wall on the self-resetting ability and seismic performance of the frame-self-reset rocking wall structure is studied.The results show that with the increase of the spacing of the prestressing tendons in the rockong wall,the self-resetting ability and seismic performance of the structure are gradually improved.(3)The rigid connecting rod between the self-reset rocking wall structure and the frame is replaced by a metal damper,and the frame-self-reset energy-consuming rocking wall structure is established,at the same time a method for determining the yield strength of metal dampers is proposed,by comparing the calculated results,the self-resetting ability and seismic performance of frame-self-reset energy-consuming rocking wall structure are analyzed.The results show that the frame-self-reset energy-consuming rocking wall structure can effectively improve the self-resetting ability and seismic performance of the original frame structure;Compared with the frame-self-reset rocking wall structure,the self-resetting ability and seismic performance of the energy-consuming rocking wall structure have only a small decrease.Therefore,the frame-self-reset energy-consuming rocking wall structure can also effectively improve the self-resetting ability and seismic performance of the frame structure,which it also shows that the design method for determining the yield strength of metal dampers proposed in this paper is feasible.(4)By changing the stiffness of the rocking wall in the frame-self-reset energy-consuming rocking wall structure,a comparison model of five different rocking wall stiffnesses was established.,and their calculation and analysis are carried out,the effects of rocking wall stiffness on self-resetting ability and seismic performance of frame-self-reset energy-consuming rocking wall structure are compared.The results show that when the rocking wall stiffness demand ratio is 0.8,the frame-self-reset energy-consuming rocking wall structure can still effectively reduce the structural residual deformation and improve the seismic performance of the structure,so that the structure can not only meet the requirements of the seismic code,but also improve its economy.