Research On Seismic Performance Of RC Shear Walls With Slit Embedded With Re-Centring Dampers

Reinforced concrete(RC)shear walls have become the main lateral force resistant component in high-rise or super high-rise building structures due to their excellent lateral resistance performance.However,under earthquake action,RC shear walls are prone to shear failure and have poor ductility and energy dissipation capacity.Therefore,it is proposed to install vertical joints in the shear wall and connect them through energy dissipation devices to form a shear wall with vertical joint energy dissipation,in order to enhance the seismic resistance of the shear wall.However,the energy dissipation wall with slit still has severe plastic hinge zone damage and significant residual deformation,making repair difficult.In order to achieve rapid recovery of post earthquake functions,this paper proposes a new type of recentring damper based on the energy dissipation ability of variable cross-section multi slot steel plates and the re-centring ability of disc springs,and uses it to connect RC shear walls with silt,forming a RC shear wall with slit with built-in re-centring dampers.The main research content of this article includes:Based on the stress and deformation mechanism of RC shear walls with slit,a new type of re-centring damper suitable for RC shear walls with slit is developed.A mechanical model of variable cross-section energy dissipation steel plate(energy dissipation system)in a re-centring damper has been established,and a calculation method for key parameters such as yield displacement and yield shear force has been established.The design requirements for the minimum width of the cross-section have been proposed.In addition,a mechanical model of the disc spring resetting device(resetting system)in the re-centring damper was established,and the calculation methods for the stiffness and deformation of the disc spring under different combinations were given.A restoring force model for a type of re-centring damper is proposed by combining the energy dissipation system with the resetting system.Quasi-static test were conducted on variable cross-section energy dissipating steel plates,disc spring resetting devices,and new re-centring dampers.The yield mode and failure mode of the energy dissipating steel plates were investigated,and the restoring force characteristics of the disc spring were analyzed.The effect of initial preload of the disc spring on the resetting and energy dissipation capacity of the re-centring damper was studied.In addition,parameter supplementary analysis was conducted using finite element software to investigate the influence of the arrangement angle,initial pre pressure,initial stiffness ratio of the disc spring reset device to the initial stiffness ratio of the energy dissipation steel plate on the reset and energy dissipation capabilities of the self resetting damper.The research results indicate that the arrangement angle of the disc spring reset device is 45 °,the ratio of the initial stiffness of the disc spring reset device to the initial stiffness of the energy dissipation steel plate is 1.8,and the ratio of the vertical component of the initial preload of the disc spring reset device to the yield shear force should be 1.5.The energy dissipation steel plate and disc spring can fully play their role,and the reset and energy dissipation performance of the re-centring damper is good.A mechanical model of RC shear walls with slit and built-in re-centring dampers was established using the continuous link method.Theoretical calculations were conducted to derive the relationship between the vertical stiffness of the re-centring damper and the overall working coefficient of the shear wall with slit under different load conditions.The design method of the shear wall with vertical joint energy dissipation and the re-centring damper were given.Based on the proposed design method,a finite element model of a RC shear wall with slit and built-in re-centring dampers was designed and established.The energy dissipation capacity,deformation capacity,and resetting capacity of the new type of energy dissipation wall with slit were investigated,as well as the influence of the placement and quantity of re-centring dampers on the energy dissipation capacity and deformation capacity of the new type of energy dissipation wall with slit.The results show that compared with ordinary energy dissipation shear walls,the RC shear wall with silt and built-in re-centring dampers has significantly improved energy dissipation and deformation capacity,and the residual deformation of the energy dissipation steel plates arranged is relatively small,which is conducive to replacement.When the re-centring dampers are placed on the upper part of the shear wall,the energy dissipation and deformation capacity of the shear wall will be enhanced.The more re-centring dampers are placed,the energy dissipation capacity of the shear wall will be enhanced,but the deformation energy will be reduced to a certain extent.