Study On The Correlation Model Between Seismic Response And Damage Of RC Frame Structures

Seismic hazard risk monitoring is usually based on the observation system of the engineering structure,which is the carrier of seismic hazard,so as to study the damage state of engineering structure and evaluate the seismic hazard risk.The international community attaches great importance to this work.Based on the structural strong earthquake observation system,how to quantitatively evaluate the structural damage state after earthquake is a hot research topic.Based on the most widely used reinforced concrete frame structures in China,this paper studies how to use the member damage model and the structural damage index weighted method to evaluate the structural damage grade after earthquake,and provides support for the rapid assessment of structural seismic damage based on the strong earthquake observation.The main research contents and conclusions are as follows:(1)The common member damage models are introduced from the perspectives of deformation,energy,stiffness degradation and low cycle fatigue.The existing damage index weighting methods and the damage index range of each damage model corresponding to different damage states are summarized.(2)Nine reinforced concrete frame structures with different storeys and fortification intensities are designed.Open Sees is used for incremental dynamic analysis(IDA).The difference between six member damage models is compared,and it is proved that the two-parameter model based on deformation and energy can more accurately reflect the unity of the first-time displacement exceeding damage and energy accumulating damage.The damage evaluation results of the Park-Ang damage model and the Niu Ditao damage model for the reinforced concrete frame structure are reasonable.The difference of three structural damage index weighted methods is compared,and the Du Xiuli weighted method is improved,which can simultaneously consider the influence of the storey position and the storey damage degree,and effectively correct the amplification effect of Du Xiuli weighted method on structural damage index of the structure under the condition that the stroey damage index decreases from the lower stroey to the higher stroey floor.(3)The effect of the number of storeys and the fortification intensity on the seismic performance of the structure is analyzed.The results show that when the axial compression ratio and the fortification intensity remain unchanged,the structure seismic performance decreases with the increase of the number of storeys.When the axial compression ratio and the number of storeys are unchanged,the structure relative seismic performance from high to low is intensity 7,intensity 9 and intensity 8 in the case of multiple,under small,medium and large earthquakes corresponding to their respective fortification intensity.(4)Based on the structural damage index obtained by the Park-Ang damage model and the improved Duxiu weighted method,the relationship and correlation between the structural damage index and the system parameters such as t the maximum storey drift,natural vibration frequency and the top storey acceleration amplification coefficient obtained by the structural seismic response were studied.Through analysis,based on the structural natural frequency and the response of the top storey acceleration,a combination parameter with better correlation with the damage of the structure was proposed,and the nonlinear correlation model was established.