Research On The Variation Law Of Seismic Performance Of Prefabricated Shear Wall Connection Nodes With Age And The Seismic Safety Of Structures

At present,the prefabricated concrete structure is designed with the idea of "equivalent to cast-in-place",but in fact,the integrity of the fabricated joint is worse than that of the cast-in-place joint.There is a new and old concrete interface between the precast concrete and the post-cast concrete.and the mechanical properties of concrete and steel bars will degrade during the service life.These factors will affect the seismic performance of fabricated joints.As a result,the seismic performance of fabricated joints will degenerate with the extension of service period compared with cast-in-place joints.In this paper,through the dynamic cyclic loading test of the joint scale specimen of the monolithic precast shear wall structure and the numerical simulation of the joint model using ANSYS finite element software,the attenuation law of the seismic performance parameters of the joint is obtained,and the service period is established according to the Park-Ang model The damage model in which the seismic performance of internal joints attenuates with the service period is used to study the influence of different service periods on the seismic performance of the connected joints.Finally,SAP2000 software is used to perform incremental dynamic analysis on the assembled monolithic shear wall structure.According to the principle of vulnerability analysis,The seismic damage of the structure under different service periods and different ground motion intensity levels is analyzed.The main conclusions of this paper are as follows:(1)The simulation analysis of the attenuation law of the seismic performance of the connection node of the assembled monolithic shear wall structure during the service period found that the seismic performance parameters such as peak load,secant stiffness,ductility coefficient and equivalent viscous damping coefficient have basically disappeared in the first10 years.Changes have occurred.After 10 years,the seismic performance parameters have been significantly reduced,and the seismic performance of the joints has been significantly degraded,but the attenuation of the seismic performance of fabricated joints is more obvious than that of cast-in-situ joints.The seismic performance damage of the joints is studied,and the damage model of the seismic performance attenuation of the joints during the service period is established.The results show that the seismic performance of the joints is basically unchanged for the first 10 years of service,and the degradation rate is significantly accelerated after 10 years of service.(2)Incremental dynamic analysis is carried out on the finite element model of the assembled integral shear wall structure.The results show that under the premise of reaching the same level of failure state,the longer the service time,the smaller the intensity of ground motion that the structure needs to input,indicating that the structure The seismic performance gradually weakened with the increase of service time.(3)Using the results of incremental dynamic analysis to analyze the vulnerability of the assembled monolithic shear wall structure,the results show that: except that the 10-year service period is basically similar to the 0-year service period,as the service time increases,the assembly of the integral shear wall The seismic performance of the shear wall structure continues to decrease,the probability of failure of the structure under the same ground motion intensity level continues to increase,and the PGA value required for the structure to be in the same degree of failure state continues to decrease;with the assembly of the integral shear wall structure connection As the damage to the seismic performance of joints increases,the vulnerability index of commonly assembled integral shear wall structures continues to increase.