Analysis Of Deformation Of Prestressed Steel Beams With Externally Cables

Along with the advancement of science and technology, a large number of new materials and new structural design techniques find many applications in the field of structural engineering, in which a new type of pre-stressed steel structure is widely used in structural engineering. It has an important role to improve the rationality of structural design and its load capacity. Considering the new form of a combination of I-section steel girder and cable, the deformation analysis of the prestressed girder beam is carried out. This combination could increase the loading-force, improve the loading forms, enhance the stiffness of the structure, thus to enrich the use of building performance, to satisfy requirements on reducing the height of the beam and increasing span. Generally, external prestressing steel beams used in combination with flexible cable in engineering in order to to reach the safety, economical, practical and aesthetic effects.In this dissertation, geometrically nonlinear deformation a felexble cable under unifrome distribulted load and both elastic and elasto-plastic deformation of external prestressed steel beam with flexible cable are analyzed. The main wok is included as the follows:1. According to the continuum theory and in accordance with Lagrangian description of the method, governing equations in terms of the displacement for geometrically nonlinear deformation of a flexible cable are derived. By using the shooting method to numerically solve the governing equations with boundary conditions, equilibrium paths and configurations are presented for the given initial deflection curves and load parameters.2. Based on the structure of prestressed beams with externally cables, the stress and deflection of the both ends simply supported beam under the effect of the transverse uniform load are studied. Selecting different eccentricity parameters of externally cables in both ends of the beams, non-dimensional stress analysis are carried out on the beams when there is not applied uniformly distributed load and when there is uniform load applied. Considering the situation that without the axial pressure and with the axial pressure, the deflection of pre-stressed beams with external cables are analysed, showing the relationship between the relevant parameters’curves.3. Furthermore, on assumption that the materials of the beam obey the ideal elasto-plastic deformation, elasto-plastic deformation of the external prestressed steel beam uner both prestressing stage and loading stage is investigated. Deflections of the prestressed stell beam uner transverse uniform load are derived. When the beam has not yet reached the yield limit, the load-deflection relationship approximate linear relationship, when it reaches the yield limit, span deflection of prestressed girder beam also increases rapidly, which span deflection value is far less than the span deflection of the girder beam without cable.