Resilience Of Urban Transportation System In The Post-earthquake Emergency Period:Evaluation,Analysis And Optimization

The capacity of Chinese cities to cope with earthquake disasters is still not adapted to the development of urbanization.As a system with a high concentration of population and economy,cities will cause enormous losses and social influence once a strong earthquake strikes.The proposal of Resilient City provides a solution for the city to mitigate the risk of earthquake.By quantifying the city's ability of active adaptability,maintenance and quick recovery when facing uncertain risks,urban planning and management can be carried out,so as to improve the city's capacity to resist risks.The transportation system is one of the lifeline systems for earthquake relief surmount.Improving the resilience of the urban transportation system during the post-earthquake emergency response period can improve the efficiency of emergency management,reduce casualties and economic losses,and produce positive social impact.Therefore,according to the topological structure and composition characteristics of the urban transportation system and considering the traffic demand in the post-earthquake emergency period,A resilience evaluation framework system to optimize the system is proposed.The main research contents of this paper are as follows:(1)The residual effective width is proposed as the earthquake damage quantification index of urban traffic system,so the system traffic function loss is quantified based on the network topological property.Considering the spatial relationship among bridges,roads and buildings along the street,the seismic damage prediction model of urban transportation system based on resilience was established.This model can reflect the relationship between structural unit failure and loss function in the system,quantify the robustness,and provide a method for the initial input of resilience evaluation.(2)A new seismic resilience evaluation index for the post-earthquake emergency period of urban transportation system is proposed,which effectiv ely reflects connectivity,redundancy,emergency traffic demand and traffic functions.The literature on the resilience index of the transportation system is summarized,the comparison and evaluation between this index and the classical resilience index of transportation system are carried out from the aspects of conceptual analysis and example verification,which proves that the index proposed in this paper is more suitable for the resilience evaluation of the urban transportation system in the post-earthquake emergency period.(3)Considering the practical engineering constraints,an optimization model using the toughness index for the sequence for repairing the damaged road sections in the post-earthquake emergency phase is proposed,and a heuristic algorithm is designed to solve the model,in order to provide decision support for urban emergency management and improve the resilience of urban transportation system.Then the example is used to verify the feasibility of the resilience evaluation framework for urban transportation system and its applicability to the recovery optimization the post-earthquake emergency phase.