Research On Dynamic Safety Risk Assessment Of Bridge Hanging Basket Construction Based On Bayesian Network

As an indispensable construction machinery in cantilever casting construction method,hanging basket is increasingly widely used in the construction of long-span bridges.However,due to its characteristics such as large self-weight,complex mechanical equipment system and difficult construction technology,the construction safety risk is relatively high and the accident consequence is serious.Therefore,it is of great significance to study the scientific and effective bridge safety risk assessment method for bridges and to carry out dynamic safety risk management and control for the construction of the bridge industry.Firstly,this thesis analyzes the safety risk connotation and characteristics of bridge hanging basket construction in order to determine the dynamic safety risk assessment for it,and puts forward the assessment steps and methods.Taking the bridge diamond hanging basket as an example,the process flow of the hanging basket construction is decomposed in detail,and the safety influencing factors of each construction process are analyzed.Based on the analysis of the factors affecting the safety of each construction process,the hazard sources in hanging basket construction are classified and identified according to the definition of hazard sources.And,amending and supplementing the list of hazard sources by expert investigation method and on-site investigation method.This list of hazard sources lays a foundation for the follow-up dynamic safety risk assessment.Secondly,the fault tree,fuzzy theory and Bayesian network are combined to build a dynamic safety risk assessment model of bridge hanging basket based on accident types.In this paper,fault tree analysis is used to analyze the causal relationship between bridge hanging basket risk events and hazard sources.Taking collapse accident as an example,the method of establishing fault tree model of bridge hanging basket accident is illustrated.The Bayesian network model is obtained through the transformation relationship between the fault tree analysis and the Bayesian network.The parameters of Bayesian network model are determined by combining expert survey method and survey data.The expert’s fuzzy evaluation information is transformed into the determined network node probability by using the fuzzy theory.Referring to relevant standards,the safety risk grading and risk acceptability criteria for bridge travelling basket are established.Finally,taking the collapse risk of H-Bridge project as an example,the application of Bayesian network analysis method in dynamic safety risk assessment based on accident type in bridge hanging basket construction is discussed.The calculation results show that the hazard level of the collapse accident of the H-Bridge project is II,and the risk is acceptable.The evaluation results are consistent with the actual operation of the project,which verifies the practicability and scientificity of the Bayesian network model.