Life Cycle Cost Analysis Of High-speed Railway Continuous Girder Bridge Under Earthquake

In recent years,the bridge instead of road mode has been widely used in the construction of high-speed railway in China,and continuous beam bridge has become the most commonly used bridge type on high-speed railway line.In order to ensure the safety of continuous beam bridge under earthquake,scholars have done a lot of research on its seismic performance,isolation mechanism and the application of isolation technology.At present,the concept of performance-based seismic design is constantly developing,the mechanical properties and economy of the structure are important components of the performance-based seismic design,but the domestic pay more attention to the mechanical properties of engineering structures,and the economic research on the structure in the whole life cycle is insufficient.Based on the above latest achievements,this thesis analyzes the life cycle cost of high-speed railway continuous beam bridge under earthquake on the basis of performance-based engineering theory framework.The main areas of this study are as follows:(1)This paper expounds the development of life cycle cost analysis,introduces the research status of life cycle cost analysis considering the natural disasters,and summarizes the research status of life cycle cost analysis in the design decision of bridge seismic and seismic isolation.(2)Based on the performance-based engineering theory framework proposed by the Pacific Earthquake Engineering Research Center(PEER).The life cycle cost calculation model of the bridge under earthquake is established seismic hazard analysis,structure analysis,seismic vulnerability analysis and seismic loss analysis.(3)Taking a continuous beam bridge of high-speed railway as the research object,the seismic vulnerability analysis of an example bridge is carried out by using incremental dynamic analysis method.According to the convolution of site earthquake risk and earthquake vulnerability,and considering the influence of discount rate,the probability of bridge earthquake risk is calculated by numerical integration method and analytical function method,respectively,and the cost of earthquake loss is evaluated for the whole life cycle of the bridge.Through comparative analysis,the calculation method suitable for bridge cost preliminary evaluation and fine analysis is determined.(4)In order to evaluate the rationality of seismic isolation design of continuous beam bridge from the aspects of seismic performance and economy,a large-span continuous beam bridge with high-speed railway in high-strength seismic area is designed to analyze the seismic vulnerability of bridge system.Based on the minimum cost criterion of the whole life cycle,the economy of each scheme of the bridge is discussed.In this paper,the research method of bridge seismic isolation scheme can effectively make up for the lack of consideration of seismic performance and neglect of economic benefit in bridge seismic isolation design,and realize the two-objective evaluation of seismic performance and economic benefit,which provides a new idea for rational decision-making of bridge seismic isolation scheme.