Research On Seismic Resilience Evaluation Of RC Frame Structure Based On Numerical Simulation And Shaking Table Test

In recent years,the concept of "Resilience-Based Seismic Design" has become the focus of research on disaster prevention and mitigation in China.This concept needs to improve the post-earthquake recovery capacity of structures on the basis of meeting the performance requirements.Therefore,the seismic resilience not only needs to consider the structural behavior,but also needs to consider its post-earthquake recovery capacity.Among them,the seismic resilience of a single building structure is an important foundation to ensure the development and application of this concept.In this paper,models for evaluating the resilience of reinforced concrete frame structures based on simulation and shaking table tests is proposed.The main research contents are as follows.(1)In this paper,a simulation-based model for evaluating the resilience of corroded reinforced concrete frames is proposed.A time-varying corrosion damage model based on fiber beam elements is adopted,which comprehensively considers most of the potential corrosion damage modes of reinforced concrete,including the loss of reinforcement section and the deterioration of reinforcement compressive buckling effect,and cover concrete and core concrete degradation,and the strain penetration effect deterioration.The Open Sees finite element numerical models of the frame structure in the uncorroded state and the corrosion rate of 5%,10% and 15% were established.Through nonlinear static analyses,the relationship between the base shear and the top displacement of the structure is obtained,and then the system function loss of the structure before the earthquake considering the corrosion state is obtained;Through nonlinear time history analyses,the relationship between the maximum interstory displacement angle and the peak acceleration of ground motion(Peak Ground Acceleration,PGA)is obtained,and the fragility curves of the structure under different corrosion rates are obtained,and then the loss of system function due to earthquakes is obtained.Linear,triangular,and negative exponent recovery functions are considered,and the post-earthquake repair time was determined according to the damage degree of the structure,and the seismic resilience of the structure under different seismic intensities and corrosion rates was calculated.The results show that when PGA is less than 0.2g,the seismic resilience remains basically unchanged.When PGA exceeds 0.2g,the seismic resilience curve of the structure has a significant downward trend with the increase of the seismic intensity.When PGA reaches 0.8g,the seismic resilience of the structure with a corrosion rate of 15% decreases to 0.51;Besides,when the corrosion rate is lower than 10%,the seismic resilience of the structure decreases with the increase of the corrosion rate.But when the corrosion rate is greater than 10%,the seismic resilience curves basically keep the same.(2)In this paper,a model for evaluating the resilience of corroded reinforced concrete frames based on shaking table tests is proposed.Based on the seismic design code of the structure,a 1/2 scale single-span,two-story two-way reinforced concrete frame structure is designed.The acceleration response,displacement response,self-resonance frequency and damage degree of the structure under different peak ground accelerations are studied by performing shake table tests on the frame structure.Then,the structure was repaired four times by using carbon fiber reinforced composite materials,and the natural vibration frequency of the structure after each repair was recorded.Meanwhile,the seismic performance and dynamic characteristics of the concrete frame structure after repair were studied.Through the damage index based on the natural frequency,the system function relationship is established,and the actual system function curve of the reinforced concrete frame structure is obtained.and the resilience of the frame structure is quantitatively analyzed,the results show that the seismic toughness of the concrete frame structure after multiple earthquakes is 0.61.The seismic resilience of each seismic structure in the first shaker loading stage and the second shaker loading stage is evaluated and analyzed by fitting the system function recovery curve.