Risk Assessment Of Cable-stayed Bridge On Haihe River During Operation

The cable-stayed bridge,with novel structure and outstanding landscape function,has been widely used at home and abroad for half a century.In recent 20 years,cable-stayed bridges have gained unprecedented opportunities for engineering practice in China.The basic theory,structural system research and construction technology of cable-stayed bridges have made considerable progress.With the increase of the number of retained bridges and the negative impact of operational accidents at home and abroad,the operational risk of cable-stayed bridges has increasingly become the focus of attention of the government and the public.In order to better play the service function of cable-stayed bridges and safeguard public interests,it is of great significance and practical needs to carry out the risk assessment of cable-stayed bridges.On the basis of drawing lessons from the research results of bridge operation risk and combining with the experience of operation and management of some cable-stayed bridges in Haihe River,this paper studies systematically and comprehensively the theories,methods and systems involved in the process of operation risk assessment,and constructs an operational risk assessment system of cable-stayed bridges that can be used for the bridge risk management in practice.Taking Jinhui Cable-stayed Bridge as the research object,through theoretical analysis and model calculation,it has completed the evaluation study of potential risks during operation,so as to provide theoretical and data support for the operation and management of cable-stayed bridges.On the basis of clearly defining the bridge operation risk,the paper has studied all links in the whole process of cable-stayed bridge operation risk assessment,sorted out the logical relationship among risk identification,risk analysis,risk assessment and response in detail,and established a standardized operation risk assessment procedure.Based on the study of risk assessment model applied in bridge engineering field and the structural and operational characteristics of cable-stayed bridges,the existing models are improved and selected appropriately.Analytic hierarchy process,event tree method and improved Delphi method are selected as operational risk identification and analysis models.In the study of the evaluation index system of operational risk of cable-stayed bridges,the acceptance criteria of risks are taken as the focus of study,and the acceptance criteria of risks,such as personal,society and traffic interruption,etc.are analyzed.A scientific and reasonable risk threshold is established for operational safety of cable-stayed bridges,and a risk evaluation matrix based on risk acceptance criteria is constructed.In view of the complex and unpredictable characteristics of operational risk,this paper puts forward some countermeasures,such as risk mitigation,risk transfer and risk acceptance.This paper takes Jinhui Cable-stayed Bridge as an example to verify the operability of the risk assessment system for the operation of cable-stayed bridges,and makes a detailed study of the risk of vehicle collision on cables,and finally determines the risk as Level ?.The results show that the system basically meets the needs of risk management in cable-stayed bridge operation.However,the qualitative and quantitative analysis methods and models applied focus on qualitative analysis;due to the low accuracy of quantitative analysis,it is difficult to fully and accurately reflect the probability of occurrence of various risks and the severity of risk losses during the operation of cable-stayed bridge.Therefore,the accuracy and credibility of risk assessment results still need to be improved.