Analysis Of Time-depended Reliability Of Concrete Gravity Dam Based On Gray Theory

Based on the theories of gray and concrete damage, the time-depended reliability of concrete gravity dam was analyzed and applied to the engineering. The research work involves several aspects as follows:1 By the application of gray theory, GM model was established to analyze, develop and forecast the changing disciplinarian and relationship among all random variables of gravity dam, and it is applied to analyze the time-depended reliability of structure.2 Artificial neural network, which is one of services provided from the Matlab platform, is applied to simulate the relationship between input and output in the system in order to recognize the system so that the performance function can be transformed into the random variable from the force.3 According to the geometrical meaning of reliability, a optimization model was established to describe the structural reliability and was solved by the optimization tools of Matlab platform.4 Introducing damage variable, a new functional expression was created, which was based on the four-parameter concrete model. It indicates varying damage characteristics through service period of concrete structure, so as to analyze the time-depended reliability in every stage of structural service period.5 The post Monte Carlo method was used to solve the reliability problem with great amount of calculation. This method can satisfy with the precision of reliability analysis, which was feasible in engineering.6 A feasible way to calculate reliability was obtained, and this method can improve the reliability accuracy.7 By analysis of the sensitivity of random variable, the reliability region of the random variables was established at the scope of engineering required.8 Applied to the engineering, these works are feasible in analysis of the structural time-depended reliability.