Research On The Earthquake Disaster Loss Assessment Method For Urban Areas And System Development

The earthquake in our country has the characteristics of wide distribution,heavy intensity and shallow source,etc.Due to its dynamic seismotectonic characteristics,large earthquakes(e.g.,Wenchuan,Yaan and Yushu earthquakes)have occurred and impacted substantial damage and losses on densely populated areas.Urban region is the gather area of human settlements and social wealth,which plays an important role in the development of socio-economic activities.With the development of urbanization,a large number of population and wealth swarm into an urban area,and the potential risks are increasing for the urban area.At present,theories and systems of earthquake loss assessment for urban areas have been researched widely,and also,lots of research results have been obtained.However,there is no systematic loss estimation and risk assessment methods and application platforms in our country,which greatly hinder the government's disaster prevention and emergency management.Based on the demand of earthquake disaster preparedness and mitigation in our country,the China-based earthquake loss assessment method and integrated system are obtained,which can provide strong support for earthquake prevention,disaster mitigation and emergency relief of government.The main research work is listed as follows:1.Based on the severe demand of disaster reduction,an extended earthquake disaster loss assessment framework was established,which organically combined the seismic hazard,time-dependent seismic fragility analysis of multi-aged buildings,socioecomomic loss assessment,as well as the basic data acquisition and database building.The improvement of methods provides theoretical support for the government's emergency decision-making,risk assessment and recovery as well as reconstruction.2.A systematic summary of the CPSHA and DSHA method was conducted and based on the determination of the scenario earthquake,the relationship between the two methods was discussed.Finally,a case study was carried out and discussed in this paper.Studies had shown that probabilistic-scenario earthquake-deterministic seismic hazard analysis of the overall consistency of the method,which can evaluate the potential earthquake risk in the study area,also can be calibrated with determined magnitude and source in a probabilistic manner,and provides clear guidance for the government's emergency rescue and disaster prevention planning.3.Study on the time-dependent seismic fragility analysis of multi-aged buildings.Firstly,a detailed,extensible building typology was proposed,considering the differences of Chinese seismic code,the structure seismic fortification intensity,the performance degradation of multi-aged buildings under different environmental characteristics,and also considering other parameters(such as plane regularity,building condition,etc.),so as to defining the performance difference between ordinary buildings.Secondly,a timedependent seismic fragility analysis method of multi-aged RC buildings with reinforcement corrosion was put forward,and also seismic fragility functions of typical structures under different degradation performances were established.Finally,a seismic fragility curve management system was developed based on C#,which can effectively integrate,conversion,storage curves.4.A direct economic loss assessment model was put forward,which can assess structure loss,decoration loss and content loss by considering the regional economic differences,occupancy,etc.At the same time,a casualties estimation model was obtained by considering structure types,occupancy,people in door rate and casualty rate.5.Study on the data acquisition method and database building.Firstly,a communityor neighborhood committees-based data collection method was obtained by using the methods of questionnaire survey,on-site consultation and mobile GIS field acquisition tool and other methods,which greatly improve the efficiency of the collection.Secondly,based on mobile GIS technology and Android operating system,a field collection system for urban building information based on Android was developed with the advantage of high efficiency,rapid and sharability.Finally,Using “ArcSDE technology + Geodatabase model” mode,a scalable,renewable,shareable database was constructed,which provide data support for the earthquake disaster loss assessment and government emergency rescue.6.Based on the foregoing method and the existing system platforms,a GIS-based earthquake disaster loss assessment system was developed,by using the ArcGIS Engine technology,“.NET” platform,and C/S structure design.The development environment,target,structure design,function design,key technology as well as software and hardware requirements,system function module development were elaborated.Finally,the assessment system was used for the demonstration area(Baqiao)as a preliminary case study.Based on the basic data of Baqiao District,the seismic hazard,structural seismic fragility,earthquake disaster losses(direct economic losses and casualties,etc.)of regional were evaluated and analyzed.The results provided theoretical guidance for the government's prevention plan and emergency plan before earthquake,and emergency relief and functional recovery and reconstruction after an earthquake,etc.