Study On Bridge Structure Uncertainty Interval Analysis Method And Its Application

Design and analysis of engineering structures are usually based on certain physical parameters.In fact,different types of uncertainties exist in engineering structures,such as geological parameters,material properties,geometry,boundary conditions and initial load state.These different types of uncertainty affects structure response.So the analysis of engineering structure must consider these uncertain factors.The analysis methods of processing engineering structure uncertainty: stochastic analysis method,fuzzy analysis method and interval analysis method.The interval analysis method.is applied to the situations of lack of statistical information and only knowing the uncertain parameter range of Engineering structure.In this dissertation,the difficulties of interval analysis method are studied.And it is applied to the calculation of bridge structure.The main contents are as follows:(1)An overview of the development of engineering structure uncertainty analysis and interval analysis was present.The studies of interval analysis method are summarized in the following four aspects: the interval finite element method,the non-probabilistic reliability analysis,interval model inversion analysis,interval parameter optimization.(2)The theory of interval mathematics,the interval finite element,the direct solution of interval finite element method,the iterative method,the combinatorial solution method,the optimal solution and the perturbation method is introduced.(3)An interval finite element method based on the discrete element method is presented to solve the problem of interval expansion in interval arithmetic.Accordi ng to the characteristics of the interval parameters in the discrete finite element method,a new solution method is proposed by combining the combination method and the perturbation method.(4)The secondary development of the Open toolbox of MATLAB software was done.The program achieve the functions of the generation of the stiffness matrix and the constraint matrix,applying loads and boundary conditions,solution method by the combination sub-interval perturbation method.Combined with the program and Monte-Carlo interval finite element method,the truss structure and the two story frame are analyzed and the correctness of the paper's method is verified.(5)The uncertainty interval analysis of a pre-stressed continuous box girder bridge is carried out and the influence of the parameters on the displacement is evaluated.