Near-real-time Seismic Damage Assessment Method Using Recorded Ground Motion

Earthquakes will not only cause severe damage to buildings,but also trigger a series of secondary disasters,e.g.earthquake-induced landslides(EQILs),aftershocks,etc.,which seriously threaten human lives and properties.A scientific and reasonable near-real-time seismic damage assessment can provide important reference information for post-earthquake emergency rescue,which is an effective way to reduce human casualties and economic losses caused by earthquakes.This work focuses on critical issues in the near-real-time seismic damage assessment:(1)earthquake input,(2)seismic damage assessment of buildings,EQILs and regional buildings under mainshock-aftershocks(MS-AS).Following works are performed:(1)A multiple levels of detail(multi-LOD)near-real-time seismic damage assessment framework is proposed.The framework is based on recorded ground motion,including multi-LOD buildings seismic damage assessment module and secondary disasters assessment module.Based on this framework,the influence of multi-LODs building inventory on seismic damage results is analyzed.Under this framework,users can choose the appropriate LOD method to carry out near-real-time seismic damage assessment according to the available data,the computational capacity and the time limit.(2)For the earthquake input,a regional ground motion simulation method is proposed based on the recorded strong motions and the continuous wavelet transform method.An evaluation measure for the accuracy of the predicted ground motion,i.e.,the response-spectrum error,is introduced.The response-spectrum errors under different site conditions,distances,and elevation differences are analyzed,and its relationship with the seismic damage of regional buildings is determined.The application conditions for the proposed method are subsequently outlined.The 1679 Sanhe-Pinggu earthquake and an M_w 7.0 simulated earthquake scenarios on the Hayward fault are examined as case study to validate the method.For locations that do not meet the application conditions,the method of modifying the ground motion prediction equation is recommended to determine the response spectrum at that location.(3)Based on the recorded ground motion and city-scale nonlinear time-history analysis(THA)method,a near-real-time building seismic damage assessment method is proposed,the database of the buildings in the target areas is established,and a corresponding earthquake damage prompt assessment system,RED-ACT,is developed.The proposed method has been successfully used in many earthquakes around the world.The accuracy and reliability of the method are illustrated through typical earthquake cases.(4)The mapping relationship between the Global Lithological Map database and the engineering lithology classification is established.Based on recorded ground motions and the Newmark sliding block method,a near-real-time prediction method for EQILs is proposed.The commonly used Newmark displacement models and the Newmark sliding block method are compared in this work to demonstrate the necessity of THA.The reliability and rationality of the proposed method are verified by comparing it with the actual earthquakes.(5)An MS-AS sequence generation method that considering multiple parameters for target aftershock is proposed.Combined with the city-scale nonlinear THA,a framework for predicting the regional seismic damage of buildings under the MS-AS sequence is proposed.The accuracy and reliability of the city-scale nonlinear THA for the MS-AS sequence are validated with the as-recorded seismic responses of buildings,the simulation results in published literature and finite element models.The Longtoushan Town damaged in the Ludian Earthquake is used as a case study to illustrate the advantages of the proposed framework.