Study On Optimization Of Bridge Structure On Whole Life Based On Reliability

As the artwork,bridge contains the wisdom and sweat of engineers.The design period of works is up to 100 years.When optimization the design of bridge not only the states of the structure at the beginning should be considered,but also the design,maintenance and inspection and other factors,throughout the life cycle,which impact on the structural economy and durability.However,the design variables optimization of bridge structure,especially for the complex cross-section bridge has been inefficient,for a long time.The choice of optimal maintenance actions is based on time and does not take into account the effects of deterioration randomness.There is no systematic consideration of the effects of deterioration,maintenance and inspection in the whole life cycle of bridge structures and the analysis in full probability.Therefore,the main research work and conclusions are as follows:(1)For the problem that the variables' number is variable and the optimization efficiency is low,the whole optimization to the complex section of bridge structure.The optimization platform independent of section type is constructed.It can enhance the applicability of the optimization scheme.The intermediate variables which are independent of the section type are selected to optimize step by step,which reduces the number of variables directly optimized and improves the optimization efficiency.(2)The health state change model of bridge structure is analyzed.Combined with full probability and discrete mathematical methods,a reliability based optimization model for life-span maintenance strategy of bridge structures is established.The maintenance strategy is established on the basis of the health status of the structure.A simple supported truss girder bridge is selected as the research object,and the optimal maintenance scheme is obtained.(3)Based on the influence caused by the deterioration,maintenance and testing randomness of the bridge structure during the whole life cycle,the optimization decision of the health state in the structure is established as the criterion.It makes the optimization scheme universal in the whole life cycle.(4)This paper systematically analyzes the change of the health state of the bridge structure in the design,maintenance and inspection,and establishes a variable joint optimization scheme.The shortcomings of the great iterations of the optimization scheme are improved,and an efficient optimization scheme is established.(5)Based on the theoretical foundation of efficient optimization scheme,the self-anchored truss suspension bridge is taken as the research object,and the mathematicalmodel is established and solved by MATLAB.The best plan of bridge design,maintenance and inspection during its whole life cycle is obtained.The layout and variation of important structural components in the whole life cycle are analyzed,which can provide effective guidance for the management and operation of the service period.