Risk Analysis Of The Construction Of Long-Span Arch Bridges For Cable Hoisting Construction

With China’s national economic and social development entering the 14 th Five-Year Planning period,the transportation industry has ushered in a huge development opportunity.Under the background of implementing the rural revitalization strategy,the bridge construction in mountainous areas has also ushered in a rapid development.Cable-hoisting concrete arch bridge has mature construction technology,wide application and strong competitiveness in mountain bridge construction.In recent years,it has been widely practiced in Yunnan-Guizhou area.However,because the bridge construction itself is a high-risk activity,especially the complex geographical environment and geological conditions in mountainous areas,there are many potential risks in the construction process of this kind of bridge,and construction accidents frequently occur,which brings great challenges to the project safety management.At present,in view of the lack of research on the construction risk of this kind of bridge,this thesis has carried out the following research according to the related research results of bridge risk and the characteristics of cable hoisting arch bridge construction:(1)This thesis summarizes the research achievements of bridge construction risk assessment at present stage,defines the definition and measurement methods of bridge construction risk according to the related bridge construction risk assessment theories,further explains the mechanism and characteristics of bridge construction risk,and sums up the selection principles of bridge construction risk assessment methods by combing common risk assessment methods.(2)Taking the "Deyu Expressway Wujiang Special Bridge" as an example,combined with the idea of analytic hierarchy,the risk source identification was carried out for the relying project,and a list of risk source censuses was established;The weight of each risk factor was calculated by using the analytic hierarchy method,and the relative importance of the risk factors at different levels was ranked.(3)Using fuzzy comprehensive evaluation method,the evaluation model of risk probability and risk loss grade is constructed,and the calculation methods of risk occurrence probability and loss size are given.By constructing the risk matrix evaluation model based on ALARP acceptance principle,the method of determining the risk level and the risk control strategy are given.(4)The theory of risk element transfer is introduced,and the related parameters of risk element are calculated by decision evaluation and laboratory(DEMATEL)algorithm,and the risk element transfer network is constructed to carry out the dynamic evaluation of bridge construction risk.By using Bayesian network to carry out forward reasoning,backward reasoning and sensitivity analysis,the risk elements and main risk chains are identified,the dynamic risk assessment of bridge construction is completed,and the risk assessment system of cable hoisting construction arch bridge is improved.