Construction Risk Analysis Of Long Span Cantilever Arch Bridge Based On Bayesian Network

At present,China is in the stage of rapid economic development,with the increasing number of bridge construction,the safety risk accidents in the construction process are more and more frequent,causing serious social impact.It is urgent to strengthen the construction risk assessment and risk control.The long-span cantilever cast-in-place arch bridge has good economic and social benefits,but it is rarely used in our country,and there are great risks in the construction process.Based on the existing theories and methods of construction risk analysis,this paper takes the construction process of cantilever cast-in-place arch bridge as the research object,focusing on the following aspectsFirstly,the basic concept of risk is defined,and the risk analysis method in related fields is used for reference to determine the risk analysis ideas of bridge construction.This paper defines the elements and characteristics of the construction safety risk of the cantilever cast-in-place arch bridge,and puts forward the risk analysis method of the construction safety of the cantilever cast-in-place arch bridge.Secondly,the identification steps of the construction risk sources of the cantilever cast-in-place arch bridge are made clear.Taking the construction process of the cantilever cast-in-place arch bridge as the main line,the structural and personnel safety risks are divided,and the safety influencing factors of each construction process are described in detail.The construction safety risk sources are identified through on-site investigation and expert supplement,and the safety risk source list of the cantilever cast-in-place arch bridge is formed.This paper studies the structure and theory of Bayesian network,determines the advantages of Bayesian network structure for construction risk analysis,establishes the Bayesian model for construction risk analysis of cantilever cast-in-place arch bridge,and puts forward the method of determining the key node parameters of Bayesian network with triangular fuzzy number.Taking the hanging basket risk source of cantilever cast-in-place arch bridge construction as an example,the applicability of Bayesian network structure is calculated,and the probability calculation of hanging basket risk source of cantilever cast-in-place arch bridge construction is realized.Referring to the guideline for safety risk assessment of highway bridge and tunnel engineering construction and combining with the calculation results of Bayesian network,the risk source assessment method and risk control principles and measures of cantilever cast-in-place arch bridge are established.Finally,the Houhe bridge is taken as an example to conduct a comprehensive risk source identification,risk source classification,Bayesian network structure topology,risk source probability calculation and evaluation,and verify the practicability of the proposed triangular fuzzy number method to determine the key node parameters of Bayesian network.The calculation results show that the construction safety risk level of Houhe bridge is grade III.According to the evaluation results,based on the construction risk control principle of cantilever arch bridge,the construction risk countermeasures of Houhe bridge are given.