Research On Key Technologies Of New Type Stiffening Girder Suspension Bridge In Mountain Area

In bridge construction of connecting villages in the western mountain, as investment is limited, choosing light stiffening girder suspension bridge type is more economical when the bridge is spanned over the wide river. But the construction cost of shallow stiffening girder suspension bridge with traditional techniques is still too high for the backward rural areas. So it is important to improve the security and stability of shallow stiffening girder suspension bridge, and bring down maintenance costs later。This thesis researches a new type of suspension bridge stiffening girder technology, with the purpose that it has more superior performance and more reliable through research。New stiffening girder suspension bridge adopts a castellated steel and concrete composite structure, which has obvious advantages of structural stability in light load span suspension bridge。This thesis analyses mechanical properties and damaging characteristics depth of castellated steel and concrete composite structure with the combination of theoretical analysis,experimental research and numerical simulation. Mainly including the following:Firstly, the construction features, economic performance, computational theory and the failure modes of the castellated beam is introduced, as well as the stress change when loading on the hexagonal-hole castellated beam and the stress distribution when changing opening rate is researched. It also briefly describes the mechanical properties of composite beams structure。Secondly, according to mechanics principle, it has done qualitative analysis on the load transfer pathway and the force mechanism of the new type of composite beam cross section, which indicates the uncertainty factors of the load transfer pathway and the need to study parameters by finite element method calculation and thus obtaining eight computing model of different load positions, different load transfer and the different boundary conditions, and the results are analyzed and compared in detail。Once more, in order to further clarify the uncertain parameters of the steel and concrete composite parts in load transfer, the thesis uses mutual authentication method by comparing with large scale model test and variety of finite element model, using finite element model result to guide the manufacture of the model experimental with the static model test to calibrate the finite element model. Through analysis and comparing the deviation of the theoretical calculation and model test to improve the structure techniques of the type of finite element modeling, optimize the design of such structures and provide the basis for wide application of the type of bridge。Finally, on the basis of theoretical analysis and model test, selecting the right material constitutive and slip curve, utilizing nonlinear finite element model., it analyses the nonlinear characteristics of concrete slabs,beams and steel beams. By means of comparing test and analysis result, it analyses the stress and deflection of the concrete and steel beam structure to obtain the load-slip curve of the castellated steel and concrete composite structure, and provide reference for the design of such bridge structure。...