Analysis Procedure And Evaluation Method For Seismic Resilience Of Urban Bridge Networks

Urban bridges are important infrastructure that affects regional economy and social community.When subjected to strong earthquakes and other disasters,the seismic performance of urban bridge structures,especially the resilience of the transportation network system composed with key bridges,are very important to social stability and regional development.Since the performance-based seismic design method was proposed,the seismic resilience drawn more and more researchers’ interest.Resilience focuses on the disaster resistant preparedness capacity and disaster-bearing capacity.These two capacities guarantee the bridge functionality sustainability and functionality recovery after disaster.Therefore,it is necessary to integrate seismic resilience into seismic performance evaluation of bridge networks.The main research contents of this study are:(1)The framework of analysis and evaluation methods for seismic resilience of urban bridge is further improved.The recovery process is related to the residual functionality,the idle time and the repairing time.The key factors of the recovery process are included in the framework of the analysis and evaluation method for seismic resilience of urban bridge.The influence of earthquake and aging effects are considered in the framework.With Monte Carlo simulation,the idle time,the residual functionality and the repairing time are calculated considering uncertainty.The seismic resilience using different repair mode is evaluated.According to different resilience performance indexes,which can serve the emergency management department as the prevention method and decision-making method for seismic disaster reduction.(2)A general probabilistic function recovery model for bridge seismic resilience evaluation is proposed.The influence of different recovery models adopted in the seismic resilience performance evaluation is analyzed.According to different damage states,various recovery strategies are given.Then the seismic resilience,recovery time,recovery improvement index and economic loss of different recovery strategies are calculated.Such that,the decision making with different risk situations can be proposed based on different recovery strategies.(3)A framework of probabilistic assessment of resilience of bridge networks is proposed.This paper provides a method for pre-earthquake retrofit optimization of bridge networks to mitigate seismic damage.The approach integrates economic loss,seismic resilience and total retrofit cost with multi-objective optimization technique to obtain the optimum bridge network retrofit planning to assist the decision maker.