The Study On Ultimate Bearing Capacity Of Long-Span Continuous Rigid Frame Bridge

At present, Long-span continuous rigid frame bridge is popular for bridge construction because of its concise structure, strong in adaptability, simple in construction, few in investment, high in benefit and so on. By analyzing the stability theory and calculating San Shui Second bridge, a practical rigid frame bridge, we could find the failure features of Long-span continuous bridge, which is the scientific basis for design and construction. This paper will present description and analysis from the following six aspects:1. First, this paper introduces the development and trend, structures characteristic, current researching situation of ultimate bearing capacity of long-span continuous rigid frame bridge, and presents the necessity of researching the ultimate bearing capacity.2. Based on the stability theory of bridge structure and the ultimate bearing capacity analysis during the whole process of the structure, this paper points out that, researching the geometrical and material nonlinearity of structure is necessary for structural behavior of bridge structure.3. Paper introduces the analysis theory of geometrical and material nonlinearity of structure, and presents the deduction process, analytical method, differences and field of application of the U.L Formulation and T.L Formulation.4. Paper introduces the analysis theory of material nonlinearity of structure. And the chapter elaborates the material nonlinearity of iron and concrete, points out increment theory elastic plastic matrix and plastic matrix, the analysis of finite element of elastic plastic of beam element.5. Paper introduces the resolution method of non-linear equation and convergence rule and the analysis theory of the program of MIDAS/Civil. Paper points out that the common resolution method of non-linear equation includes: direct solution, incremental method, New-Raphson method and mixed method. And, paper introduces the theoretic foundation and implementation method of geometrical and material nonlinearity of bridge structure in MIDAS/Civil.6. Final, according to the practice project, the ultimate bearing capacity of the 9 kinds load conditions, which happened during the longest cantilever construction stage and bridge construction stage, were calculated by the finite element program, MIDAS/Civil. Through, analyzing the result of the buckling and geometrical and material nonlinearity finds failure features of bridge structure.