Research On Evaluation Methodology Of Seismic Safety And Resilience For Significant Buildings

With the development of earthquake engineering and the promotion of social economy level,the requirements for seismic precaution of buildings is shifting from guaranteeing the basic life safety,to ensuring the double safety of life and property,to ensuring higher targeted function security.The seismic criterion is transforming from traditional "no damage under frequent earthquakes,repairable under fortification earthquakes,no collapse under rare earthquakes",to " perfect under frequent earthquakes,no damage under fortification earthquakes,repairable under rare earthquakes,no collapse under extreme rare earthquakes",to performance-based and resilience-based seismic design.However,for significant buildings belonging to special fortification and key fortification classes,the reality and demand of seismic safety and resilience levels are both unclear.Therefore,an objective evaluation standard and technology system is urgent needed to evaluate the seismic safety and resilience levels,to provide method and basis for improving the overall ability of seismic mitigation.Based on this,a preliminary research has been conducted on evaluation methodology of seismic safety and resilience for significant buildings.The main study contents and achievements of this paper are as follows:1.The topic related research status are reviewed,including the proposing and development of resilience-based seismic theory and method,the resilience research progress of structural and nonstructual systems,in order to provide a theoretical basis for later study.2.The seismic fragility of typical nonstructual systems of significant buildings are studied.Based on literature statistics,numerical simulation and experimental validation,the seismic fragility of nonstructual systems of acceleration-sensitive,displacementsensitive and mixed-sensitive types are studied,the seismic fragility curves of which are also given.Of which,focusing on relic-stored cabinet,a damping device with silicone dampers is designed.Through numerical simulation and experimental validation,the seismic performance and fragility of cabinets with and without damping device are both studied,to verify the effectiveness of the damping device and the reliability of the seismic fragility results.3.The evaluation methodology of seismic safety for significant buildings is proposed.The study work includes the definition,level standard,evaluation indexes and evaluation process of the seismic safety.Based on seismic fragility analysis,the calculation methods of damage indexes of structural and nonstructual systems and seismic safety index are put forward.The relationship between seismic safety index and seismic safety level is also analysed.The evaluation methodology of seismic safety for significant buildings is finally developed.4.The evaluation methodology of seismic resilience for significant buildings is proposed.The study work includes the definition,level standard,evaluation indexes and evaluation process of the seismic resilience.Based on seismic safety methodology,the relationship between damage index and functional loss is studied,and the calculation methods of functional loss and recovery time are put forward.The relationship between seismic resilience index and seismic resilience level is analysed.The functional recovery curve of building after earthquake is also given.The evaluation methodology of seismic resilience for significant buildings is finally developed.5.Engineering cases of significant medical building and nuclear island construction are selected to evaluate the seismic safety and resilience levels of these buildings with tradition seismic technique and isolation seismic technique,to verify the reasonability and practicability of the proposed evaluation methods,meanwhile to analyze the effectiveness of seismic isolation technique in improving the seismic safety and resilience levels.For medical building case,the traditional seismic scheme and isolation seismic scheme used in complex hospital building are studied respectively.The seismic safety and resilience levels of building under frequent,fortification and rare earthquakes of 8 degree levels are evaluated.Results show that,the seismic isolation technique can effectively improve the seismic safety and resilience levels of medical buildings,and improve the recovery speed after earthquakes,which proves that the seismic isolation technique has obvious advantages in the field of seismic mitigation and is necessary to be promoted.For nuclear power construction case,the traditional seismic scheme,multi lead-core rubber bearing(MLRB)isolation scheme and eradi quake system(EQS)isolation scheme used in APR1400 nuclear power plant are studied respectively.The seismic safety and resilience levels of plant under OBE(0.5g)and SSE(0.835g)levels are evaluated.Results show that,intelligent use of the seismic isolation technique can effectively improve the seismic safety and resilience levels of nuclear power construction,and improve overall seismic mitigation ability.It’s worth noting that the isolation technique must be argumented and evaluated carefully before practical application,considering the possible problems and risks it may lead to.