The Remaining Service Life Forecast Of Existing Reinforced Concrete Beam Bridge Based On The Time-Varying Reliability

With the changing natural conditions, economic development caused by increased trafficand load rating, bridges is facing unprecedented challenges. Among the many factors workingtogether, with the passage of time, reinforced concrete bridge structure would lead to differentdegrees of injuries.these injuries often include damage to materials, components and struc-tures. Accumulating various injuries certainly caused the bridges’performance deterioration,carrying capacity and durability declined. Ultimately affect its normal use and pose a safetyhazard. How scientificly and rationally assessment of the reliability of existing reinforcedconcrete bridges and predict its remaining life, has become one of the key issues of academicresearch of domestic and foreign bridge.Through research on the reliability of existing reinforced concrete bridge structures andprediction the remaining service life, on the one hand, it can guide the bridge design, con-struction and safe operation; on the other hand, it can reveal potential crisis in the existingbridge and timely make the decision whether to repair and reinforcement it or demolition andreconstruction.Theoretical basis of this article is time-varying reliability theory, combined the researchof material durability, starting with the reliability and service life of existing reinforced con-crete simply supported beam bridge were studied and analyzed. The main contents as follows:Firstly, the existing evaluation methods of existing concrete bridge and the research sta-tus were summarized and commented, laid the theoretical foundation of this article.In practice, when the bridge operator, its resistance is affected by many factors,and it is adecay process with time and nonrecoverable, so we should be treated resistance as a randomprocess. It can be seen reliability assessment of the bridge structure should be a time-varyingproblems, this paper draws on the results of previous studies on the structure of the resistancefactors, case of the actual background, the mathematical model of calculating the resistance,load probability model and resistance attenuation model were made.Because of the questions of resistance to decay with time, we should analysis of the ef-fects of resistance such as concrete carbonation, steel reinforcement corrosion and intensitychanges. In calculating the reliability index, resistance random process needs to be convertedto a form of random variables, and requires iterative calculator, therefore, we solved thisquestion using MATLAB programming.Finally, combined with a practical project case, using the time-varying reliability indica-tor calculation program calculated the time-varying reliability indicator of the reinforced con-crete simply supported bridge which is consisted by eight T-beams and its length is20meters.By comparing the results with the target reliability index we can get the remaining life of the bridge.