Study On Optimal Maintenance Time Of Concrete Bridge Members Based On Different Failure Criteria

Bridge construction in China high-speed development,China has built a large number of bridges,so many bridges need more scientific maintenance management.And now the bridge exists the durability,reliability decrease,increase the maintenance cost,due to carbonation and chloride ion erosion and corrosion caused by the deterioration of concrete bridge structure,resulting in concrete bridges of different diseases,how to take measures for the maintenance of concrete bridge components,how to determine the optimal maintenance time.This paper combines the research materials at home and abroad,the related software,and expounds the definition of different failure criteria,and studies the maintenance strategy and the optimal maintenance time of the bridge under different failure criteria.The main work of this paper is as follows:The reliability theory of components and the Bias renewal theory are introduced.Firstly,the basic concept of single component reliability and the calculation and analysis method of single component reliability are introduced;Secondly,the concept and analysis method of time-varying reliability of component are introduced;Finally,the basic concepts of Bias and Bias update based on detection information are introduced.The mechanism of concrete structure degradation caused by three failure criteria of carbonation,chloride ion corrosion and steel corrosion is expounded.The physical model and reliability analysis of the three failure criteria are expounded.Then,the updating principle of Bayesian updating is used to analyze the time variation factors of concrete components after testing,and the time-dependent law of the area of corroded steel bars is also analyzed.The method of life-cycle cost analysis of bridge maintenance optimization and the composition of life cycle cost are introduced,On this basis,the maintenance of bridge components based on detection information and the calculation of inspection cost,maintenance cost and failure loss cost in later management are analyzed.Finally,the maintenance time is optimized by using genetic algorithm.This paper takes two maintenance strategies and the stone Longmen bridge as the background.The theory of knowledge through the use of introduction to the calculated carbide during the service period of the failure probability and the probability of maintenance costs,obtained for anti-corrosion coating layer coagulation and maintenance measures within a prescribed time is better than the replacement of concrete measures.According to the detection information to predict the service life of the bridge,and the calculation of the total cost management,the optimal maintenance time was optimized,the resulting failure probability is greater than the probability of failure was not detected by the detection information calculation,with the increase of service time after the detection of the degradation speed,shorten the service life.