Study On The Assessment Approach For The Aseismic Ability Of Urban Infrastructure

The earthquake has always been a serious threat of the natural disasters to the development of human society,and almost every earthquake in the history of human has bring huge losses to human society.As time goes by,our society and cities have developed into modern ones,which in turn become more vulnerable to earthquakes,especially when the natural hazard happens in or near the cities.These hazards could easily damage or even ruin the infrastructures and lifeline systems of the cities.Therefore,it is of great significance to investigate the aseismic ability of these structures,which will provide a guideline to the city administrators in protecting the city from earthquakes.The Grey Correlation Analysis and Analytic Hierarchy Process were used along with the data from previous earthquakes in this dissertation to establish an evaluation system and propose a method related to the aseismic ability of a city,so as to provide some advice for the city to withstand earthquakes.First of all,this dissertation gave a brief introduction to the earthquake and its danger to human society.Then,this dissertation reviewed some relevant works that had been done by domestic and foreign researchers and stated the development of this research field.In the second chapter of this dissertation,the seismic damage to the infrastructures of the city was investigated,and based on previous earthquakes,the properties of earthquake-caused disasters were proposed,which mainly includes the severity,complexity and chain effect.Besides,the failure characteristics of city infrastructures and lifeline system was analyzed based on the data from previous earthquakes,including six different systems,namely electronic system,transportation system,communication system,water system,gas system and underground pipe gallery.In Chapter three,the Grey Correlation Analysis was used to analyze the effects of different factors that influence the loss of infrastructures and structures.These factors contain earthquake magnitude,focal depth,time,area of seismic intensity over 7,population intensity,total population,GDP of this city,and the per capital GDP,which cover the effects of the earthquake itself,the seismic damage of the city and the development of the city.Results show that the total population contributes the most to the loss of infrastructures,and the second factor is the average GDP of the area.As for the loss of structures,the total population also makes the most contribution.Based on the results from last chapter,an evaluation system for assessing the aseismic ability of the city infrastructures was proposed by adopting reasonable indexes.These indexes include prediction ability,social financial ability,rescue ability and the aseismic ability of the infrastructures themselves.These chosen indexes covered different aspects of the earthquake.In the last chapter,the evaluation method was built after choosing rational systematic and postural indexes.The relative weight of these indexes was acquired by consulting experts in this field.Then,the grading criterion of the variable was put forward to accurately reflect the aseismic ability of different infrastructures.The relative weight of these four indexes are 0.118,0.155,0.305 and 0.402 respectively.Additionally,the values of the six subsystems are 0.345,0.103,0.035,0.207,0.241,0.069,which means the electric system contributes the most to the aseismic ability of the system.Finally,Nanjing and Yancheng were taken as examples to demonstrate the process of evaluation,and the evaluation values of them are 0.79 and 0.68,respectively,indicating that the aseismic ability of infrastructures of the two cities are both at high level according to the criterion proposed in the paper.This dissertation established an evaluation system and proposeed a method related to the aseismic ability of urban infrastructure,so as to provide a reasonable way to assess the aseismic ability of a cith and give some advice for the city to withstand earthquakes.