Dynamic Characteristics Of Large Span Cable-stayed Bridge With Random Parameters Based On Recursive Stochastic Finite Element Method

Random structures are the engineering structures in which certain physical and geometrical parameters are random quantities. Since the twentieth century, the researchers of random structures have made much great progress in the study of eigenvalue problems with random parameters. With the development of transportation in China, long span cable-stayed bridges are often designed to cross big rivers by civil engineers due to their unique structural formation and mechanical properties. Meanwhile, noting the uncertainty of structural parameters, the statistic dynamic characteristics of long span cable-stayed bridges induce more and more attentions from researchers. For large-scale and complex random structures, how to get the solution of eigenvalue problems is an important research direction in the field of civil engineering. Obviously, it is more significant to find out the solution method of large and complex structures with random parameters. Different from the stochastic FEM utilized in literatures, this article introduced a new stochastic finite element method, called as Recursive Stochastic Finite Element Method (RSFEM), which has been successfully applied to the static analysis and reliability studies of some engineering structures such as cantilever beam, clamped plate, and multi-storeys of frame and so on. This article will take a simple cable-stayed bridge model as an example to compare RSFEM and the Monte Carlo method, Considering a good approximation between RSFEM and Monte Carlo simulation method, the accuracy of results can be guaranteed, and a lot of computing time is able to be saved through RSFEM. By the solution obtained, the impact of random elastic modulus exist in the decks on the dynamic characteristics is discussed, and several conclusions are summed up in the end.The main achievements are briefly mentioned as follows:1. Brief introduction to application profiles of the cable-stayed bridge structural system engineering is considered, and display the details of graphical model process of the EDong Yangtze River bridge. And confirmed the MATLAB results of the deterministic model is correct by comparing the calculation results of the model by ANSYS and Midas/Civil, it is providing a good foundation for the next step to modal analysis of cable-stayed bridge which considering the random parameters.2. In consideration of three parts as random variables which consisted in rigidity of deck, flexural rigidity and pile soil action that is evaluated as spring stiffness of bridge structure.Then the method that used for statistical dynamic analysis of EDong Yangtze River bridge is RSFEM analysis with considering the system analysis in single or multiple random variables.3. By using MATLAB software to draw random mode of EDong Yangtze River and natural frequencies of the probability density map respectively. 4. Finally by the concrete study that based on RSFEM for three discrete types of random field distributions, which is included in beta distribution, uniform distribution and normal distribution and also with evaluation of self vibration characteristics in statistical values of the EDong Yangtze River bridge, we explore and show the application of the RSFEM for first time respectively.