Research On The Key Technologies Of Highway Bridge Risk Assessment

Highway bridges play a significant role in the social and economic benefit, while the risks they may be suffered have been paid more attention to by the government and the public. Facing more and more bridge accidents and the growth of life and property losses, the risk management system of highway bridges needs to be improved while considering the actual situation of our country, and effective risk countermeasures should be developed at the same time to deal with the risks of bridges, so as to achieve the goal of increasing bridge security. Basing on the international research results, the theoretical framework of bridge risk assessment is expatiated combined with practical experience in risk assessment of highway bridges, and key technologies of highway bridges risk assessment were studied in this thesis. Main work has been done is as follows:1. The definition of bridge risk and bridge risk assessment are given in this thesis, the generation process of bridge risks is expatiated, the content and process of bridge risk assessment and what are the key technologies of bridge risk assessment are analyzed.2. Highway bridge risk accidents management system (BAMS) was developed to provide the necessary basis for bridges risk assessment, accidents information collected in the system are simply analyzed. The system is used in this thesis to support the completion of risk identification.3. A comprehensive method that combines data method, fault tree method and check list method also proposed based on BAMS. Objective accidents and subjective risk assessors'opinions are combined together by the synthesis method of risk identification, and it will make the work of bridge risk identification more comprehensive and profound.4. Existing basic risk estimation models are summarized and improved in a unified framework of theory; response surface method was proposed to structural quantify the risk probability of structural failure; traditional Delphi method is improved to achieve the high efficiency of risk estimation based on the reliability, consistency and coordination of experts'opinions.5. The detailed bridge risk evaluation and accepted criteria are expatiated; risk countermeasures are classified into three categories by the different ways of dealing with risks based on the risk level and risk tolerance ability of risk bearer, and the characteristics of various strategies and application conditions are described.6. Finally, a seismic structural damage risk analysis of a self-anchored suspension bridge was carried out as an example to illustrate the process of risk assessment and the effectivity and practicality of the key technologies of bridge risk assessment studied in this thesis.