Research On Reliability Evaluation And Remaining Service Life Forecast Of Existing Concrete Bridge

With the action of natural environment, increasing traffic flow and vehicle load, material deterioration, the concrete bridges have undergone various degree damages on three levels of material, component and structure as time goes on. And with the accumulation of these damages, the concrete bridge's bearing capacity, performance and durability will drop or degrade, so its normal service function is influenced. How to evaluate the reliability of existing concrete bridge and to forecast bridge's remaining service life rationally, has gradually become one of the concerned problems in the domain of domestic and foreign bridge academia. At present, the research on the reliability of existing concrete bridge is not abundant, which is the starting point of this dissertation.In this dissertation, adopting the results of material durability, the reliability evaluation and remaining service life forecast methods of existing concrete bridge were studied respectively on the basis of random reliability and fuzzy reliability. The fruitful results are as follows:Firstly, the existing (or usable) evaluation methods of existing concrete bridge, the structure reliability methods, the reliability research status quo of concrete structure considering durability of materials were summarized and commented, in which the research direction was pointed out, and it also offered the theoretical foundation of the subsequent research.Considering random of variable, the reliability evaluation and remaining service life forecast method of existing concrete bridge's components was put forward relatively rounded. This part includes the following points. On the basis of stationary binomial random process for variable load's sample function, considering evaluation base period and modification factor of live load, the probability model of vehicle action effect was presented, and considering evaluation base period, the probability model of human action effect was presented. Considering durability parameters, the time-varying probability model of component resistance was offered. The reliability evaluation flow was proposed, and two reliability calculating methods referred to as the method based on evaluation load's occurrence probability and the method based on local maximum load in evaluation base period, were put forward. Proceeding from the continuity of reliability index, considering time-varying of component resistance,...