Influence Of Near And Far Field Ground Motions On Post Earthquake Resilience Of Frame Structure

Most of the previous studies on the seismic capacity of building structures are mostly expressed as the study of anti collapse ability directly related to life safety,or the vulnerability study associated with structural reliability.All of which do not directly reflect the "reduce economic losses caused by earthquakes" and "how long restore the use of function " and other problems.In 2011,the American Academy of Sciences published a research report,which pointed out that the seismic design with restorable function has become the research direction in the field of earthquake engineering in the future.Therefore,this paper carries out relevant research on the frame structure,and provides reference for the comprehensive development of our country's seismic performance evaluation research based on full probability theory,investment risk assessment and the formulation of post earthquake recovery and reconstruction plan.In this paper,based on the frame structure as the research object,based on the FEMA-P58 theory,combining with the structural features and design specifications of our country,the structural elastoplastic analysis and vulnerability analysis are used as the means,and the seismic performance evaluation software PACT can be used to quantify the repair time and repair cost after the near field pulse,near field non pulse and far field earthquakes..The restorability grade of frame infilled wall structure under three kinds of earthquake is further classified,and the recoverability curve is given.From the angle of vulnerability curve,seismic loss assessment,recoverability curve and division grade,the effect of filled wall as an unstructured component on the seismic performance of frame structure is considered on the one hand,and on the one hand,the effect of near far ground motion on the seismic response of frame structure is compared.In view of the above contents,the main work of this paper is as follows:(1)To study the vulnerability of the frame structure under near-field seismic action.27 types of near field motion records with and without pulse are selected reasonably,and PGA is used as the intensity index of the ground motion.The maximum interlayer displacement angle is used as the structural damage index.Based on the IDA method,the seismic vulnerability of the pure frame structure and the filled wall frame structure is analyzed.The vulnerability curve and vulnerability matrix of the pure frame structure and the filled wall frame structure are calculated and the difference between the frame structure and the filled wall frame structure is calculated.(2)The seismic response of the pure frame structure and the filled wall frame structure under the near and far field earthquakes is compared from the seismic response spectrum,the IDA partition curve,the interlayer displacement angle with the floor distribution and the vulnerability curve.It is found that the damage degree of the two examples under the near field pulse ground motion is higher than that of the near field earthquake.Far field seismic action is also higher than near field non pulsatile seismic action.Considering the stiffness and energy dissipation capacity of the infilled wall,the displacement angle of the structure is greatly reduced,that is,the seismic performance of the structure is increased.(3)The FEMA-P58 based seismic loss assessment theory,evaluation process and seismic recoverability definition are briefly introduced,and the evaluation grade of seismic recoverability under the standard fortification of a single building is divided.The loss and recoverable ability of pure frame and filled wall frame structure are evaluated under near and far field earthquakes.The cumulative probability distribution of repair time and repair cost is discussed,and recovery path is selected to draw a recoverable curve.From the point of view of the degree of function loss,repair time and recoverability grade,it is found that the analysis results of this example in near field non-pulse ground motion are better than the far field vibration,and the far field vibration is better than the near field pulse ground motion.In addition,considering the effect of filling wall,the repair time of the filled wall frame structure can be reduced effectively,the recovery speed is improved,the function loss is greatly reduced,the recoverable grade is improved and the recoverable ability is improved.