Research On Design Theory In Composite Material Cable-Staved Bridge

Resin-based composites (RBC), especially carbon fibre, used as a kind of bridge engineering structure material, has greatly changed the clumsiness of bridge structure, long period and complicated process in construction, and consequently has a good prospect in usage. However, it has also simultaneously brought many problems badly in need of solutions such as the enlargement of geometric non-linear effect and the obviousness of inhomogeneous changing physical parameter features. Therefore, there is some discrepancy between the practical situation and the analysis of normal finite element program about composite material cable-stayed bridges (CMCSB), which accordingly influences the safety of CMCSB.The thesis, taking the basic features of RBCM as a starting point, makes theoretical and numerical research on CMCSB from the four aspects of changing physical parameter, initial stress, box beam torsion and geometric non-linear problem. The main researching contents and contributions are as follows:1. The changing physical parameter feature of composite material upon the influence of temperature, in some cases, owing to the great geometric non-linear effect, makes the stiffness and intensity of structure greatly decreased, thus seriously influences the safety of structure. For that reason, in the case when environment is changed to a larger extent, the influence brought by the changing physical parameter feature of composite material cannot be neglected.2. The problem of initial stress arisen in RBCM structure design is an important factor in bridge structure especially in the cable-stayed bridges design. This thesis has found that, when there exists initial stress, under the long-termed loading, initial stress makes considerable effects on the level of deformation and stress , in some cases, to the extent of 30% off the normal situation.3. The simplified design theory in composite material honeycomb texture has been deduced and then verified by means of finite element.4. The torsion theory in composite material box beam structure has been deduced and the corresponding finite element pattern has been reached.5. The theoretical deduction and numerical research has been made in the bending deflection effect, the joint effect of bending moment and axial force and geometric non-linear problem in CMCSB, and the simplified calculating method of bending deflection effect put forward.Based on the above-mentioned research, the thesis has made quadratic exploitation of the finite element application program Ansys so as to guide the future design and analysis on CMCSB.