Studying On The Application Of Inverse Structural Reliability Method In The Bridge Engineering

With the development of the structural reliability theory,which is based on the Probability statistics, for one thing,we could calculate the reliable state of the structure using the structural reliability theory,for another,we need to search for the unknown deisign patameter based on the prescribed reliability index,the traditional forward structural reliability theory to deal with this problem only by trial and error. This approach sometimes is invalid, and at the same time the cost of calculation is commonly large,then the inverse reliability theory is elicited here.The inverse reliability problem has not the universal calculational methods .it has a close relation with itself and the structure of the corresponding forward reliability problem. To solve the inverse problem, the first step is to make great efforts for getting to konw it. This article firstly introduce the basic theoretics of the formward reliability, accordingly the inverse reliability theory is also put forward,the auother summarize the detailed calculational steps by the numbers, combined with the mathematical theory of Probability statistics and numerical value calculation, programming in the Matlab maths tool to circulate and check the above method.In the study of the loads on the bridge.the two common model about probability are: the permanent load which is independent of the time; use the model of random variable; the changing load which is relative to the time, could use the model of random process. This text is according to the all kinds of domestic and oversea informations to establish the load model of concrete bridge about its surplus service life, further more ,when the systemic reliability index is given , the author set a simple supproted beam existing bridge for a example to check its carrying capacity and make a forecast about the surplus service life at the same time, the detailed calculational steps is given later.The reliability evaluation of the existing bridges structure, as well as how to accurately handle the theoretics of evaluation in the strategy of the bridge reinforcement is the urgent task in engineer field. Evaluate and check the carrying capacity of the existing bridges with the method in this text, which will supply the theoretic foundation for the reinforcement design for the bridge structure.