Cornering Reinforced Concrete Truss Arch Ultimate Bearing Capacity Analysis

The paper introduces the development of arch bridges and the study status of load carrying capacity of trussed arch bridges, analyses and compares different analysis means of ultimate load carrying capacity of arch bridges and characters of several current programs. Based on Wutun trussed arch bridge, finite element models are established through computer and the ultimate load carrying capacity of this kind of RC trussed arch bridges is analyzed and studied.Because all staffs of RC trussed arch bridge mainly bear axial forces, and only bear very small bending moment near the nodes, so spatial beam cells can be adopted to simulate the structure in the paper; moreover based on the theory that the steel and concrete can work together and distort in phase, the steel and concrete of RC trussed structure can be equal to one ideal elastic-plastic combined material with dissymmetrical constitutive relation of stress-press, the constitutive relation deduced by the paper can benefit to the same kind of RC trussed structure. Furthermore, the reciprocity of peg and soil is equaled to pole-spring model. Two kinds of trussed multi-arch bridges with different structural forms are contrasted and analyzed, considered linearity, geometric nonlinearity, and dual nonlinearity respectively, and the nonlinear influence on the analysis effects of RC trussed multi-arch bridges is studied.The analysis effects indicate: In order to get accurate results, the influence of geometric nonlinearity and material nonlinearity must be considered when studying the ultimate load carrying capacity of RC trussed arch bridges. Basing on dual nonlinearity analysis means, the paper studies different original transverse departure, different load forms, different temperature change, different structural forms, and other factors bring influence on RC trussed multi-arch bridges; in all these factors, the influence of different load forms is the most prominent. Moreover the paper brings forward the process until the structures under different styles of load forms are destroyed and the structures' destroyed patterns. Three different definitions of stability assurance coefficient are discussed and the second definitions of stability assurance coefficient is suggested to measure the overall stability level of old RC trussed multi-arch bridges, itslowest allowance value of stability assurance coefficient is suggested to be 6 in the paper.The research work benefits to learning about the process until the whole trussed arch bridge structure finally failures and many influence factor on the ultimate load carrying capacity of this kind of old trussed arch bridges; provides many useful experiences and advices on evaluation of ultimate load carrying capacity of employed bridges after many years employment, overrunning capacity, security evaluation, and so on.