Study On Seismic Performance Of Friction Damper Installed In Energy-consuming Wall Toe

The second-generation seismic concept designed based on structural performance can no longer meet the requirements of the national economic and social development and urbanization process for the rapidly restore the function of the city.Based on the requirements of restorable functional cities,the concept of resilient seismic design came into being.Resilience is recoverability for individual building structures.The form of replaceable member is one of the main forms of recoverable structure,the purpose of which is to set up such components in the part of the structural component that is most damaged by the earthquake,guide the damage to concentrate on the replaceable part,thereby reducing the damage of the non-replacement part;at the same time,the replacement of the replaceable parts after the earthquake is realized to achieve the purpose of rapid repair.The application of friction damper as a replaceable part of the wall toes is one of the forms of replaceable number,and the friction damper has the advantages of stable energy consumption capacity and balanced tension and pressure.However,the study of the stability and durability of the hysteresis energy consumption of the friction damper,as well as the study of the characteristics of the friction damper applied for the wall toes,need to be further developed.In this paper,according to the size of the replaceable wall toes parts,fifteen monolithic friction dampers were designed,mainly based on the friction material,preload,the form of the bolt washer,and the thickness of the friction plate as a single variable,the low-cycle reversed axial loading test was carried out to explore the influence of the above parameters on the stability of the hysteresis energy consumption of the friction damper.Three friction dampers with different slot forms were designed,and an eccentric loading cyclic tests was conducted to explore the applicability of friction dampers of different slot forms in the wall toes parts.Finite element analysis of friction damper,and application of friction damper to shear wall for simulation analysis,to explore the applicability of damper in wall and the impact on the seismic performance of shear wall.The main contents are as follows:(1)The low-cycle reversed axial loading test of fifteen single variable friction dampers is carried out,and the test phenomenon of the specimen,the damage of the friction plate and the sliding motherboard,the hysteresis curve,the preload loss curve,the change curve of friction force,the change curve of friction coefficient,the change curve of friction coefficient with preload force,and the energy consumption capacity with the change curve of preload force are compared with each other to obtain the following conclusions:The test results show that all test friction materials can provide a hysteresis curve close to an ideal rectangle,the brass material can stably dissipate energy under high torque and has a larger friction coefficient,the initial value of the friction coefficient of soft materials such as brass and aluminum varies greatly under different preloading forces but will tend to the same stable value after multiple loading cycles,the friction coefficient of steel continues to rise and does not tend to be stable subjected to cyclic load,NAO material friction coefficient is basically stable.(2)The eccentric low cycle reversed load test is carried out on the friction damper with different slot forms,and the test results same as the axial test are also obtained,and the following conclusions are obtained by the friction dampers with different slot hole forms can stably dissipate energy under the rotation of the simulated wall toe,the larger the slot width,the worse the hysteretic stability,the narrow hole form is the better slot form for the friction damper.(3)The friction damper is carried out with the low-cycle reversed axial loading test by using ABAQUS,and the comprehensive results of the looseness of the preload force and the change of friction coefficient are simulated by adjusting the change of the preload force,and the hysteresis curve obtained can be well fitted with the test results.The influence of friction coefficient,preload and slot width on the test results is analyzed,and the selection of sliding motherboard thick Ness under different friction damper sliding force design values is discussed.(4)Using ABAQUS to simulate the replaceable shear wall with the friction damper at the wall toes proposed in this paper,the simulated skeleton curve can well fit the test results of the shear wall,which explains the rationality of model establishment.The effect of the relevant parameters on the displacement and energy dissipation of the friction damper was researched.