Research On Bridge Risk Evaluation And Operation System Resilience Measurement And Improvement Strategies

Bridges are an important part of the comprehensive transportation system,and with the development of the economy,the mileage of bridges in China has experienced rapid growth.However,with the increase in the number of bridges,there are more and more accidents during the construction and operation of bridges.In order to reduce bridge risk and achieve sustainable development of bridges,this paper conducts bridge risk evaluation and introduces the concept of resilience,which is an inherent property of the system and the ultimate goal of risk management.Improving the resilience of bridge operation system can effectively cope with risk,and conducting system resilience metric is the basis of resilience improvement,so this paper conducts research from the following aspects.(1)The establishment of bridge risk index system and weight determination.This paper establishes the construction and operation risk index system for girder bridges,arch bridges,steel frame bridges and cable-stayed bridges according to the relevant specifications and literature survey.In order to calculate the reasonableness of the weights,on this basis,the hierarchical analysis method is chosen to calculate the subjective weights of each index according to the expert scoring results,and the objective weights of each index are calculated using the entropy weight method.Finally,the subjective weights and objective weights are linearly combined by using game theory to get the combined weights of risk indicators.(2)Determination of bridge risk level.The gray system theory and the fuzzy comprehensive evaluation are combined to obtain the gray fuzzy theory,which is used to process the risk evaluation matrix obtained by expert scoring and calculate the affiliation matrix.The risk evaluation matrix is obtained by swapping the calculated combination weights and the affiliation matrix,and the risk level of the bridge is determined according to the principle of maximum affiliation.(3)Comprehensive scale of bridge transportation system.At the beginning,the structural composition of the bridge transportation system was established,and the underlying theory of the bridge transportation system was presented.Then,the text is based on the scale index and the application scene two angles,based on the relevant standards and literature,and identifies 36 system-specific factors.Root cause analysis and influencing factors condition rate.Adopted by Netica,forward causal reasoning quantitative system performance,passing backward reasoning diagnosis causes maximum failure.(4)Strategies for improving the resilience of the bridge operation system.Based on the Bayesian network and sensitivity analysis,the factors that have the greatest impact on the resilience of the bridge operation system are determined,and a static improvement strategy for system resilience is proposed for these factors.Then,based on the importance analysis,determine the influencing factors that have a greater effect on improving the probability of system toughness without failure,the influencing factors that cause a greater probability of leaf node failure,and the influencing factors that have a greater impact on system toughness in the event of complete failure,and propose corresponding improvements Strategy.