| Summary: | 碩士 === 國立高雄應用科技大學 === 土木工程與防災科技研究所 === 101 === The purpose of this paper is to perform nonlinear analysis on Swing column vehicle carried suspension bridges during construction stage. Researches were focused on suspension bridges which had rotating shafts supported design at bottom of bridge tower that it bears purely axis, shear forces, and reducing bending stresses. Study was on nonlinear analyzing on Swing column vehicle carried suspension bridge during construction stage.Research methods were, after confirmation of geometrical shapes and initial states of suspension bridges, built up analysis models using SAP2000 finite element software and carried out numerical simulations; to predict strain and internal forces spreading of main cable, bridge tower, and stiffening girder on each construction stages respectively and compared with three construction stage instances of vehicle carried suspension bridge in this paper for analysis; to study linear changes of main cable, calculated length errors of main cable and suspension cable; and to predict structural displacement and changes of internal forces of three Swing column vehicle carried suspension bridges during construction stages to ensure suspension bridges construction precision.Finally, dynamic analysis was applied on three suspension bridge construction instances.Several important discoveries were resulted by this research: (1) while building finite element models for suspension bridges designer should consider geometrical and material nonlinear interferences in addition to actual construction steps in order to predict the correspondence and displacement of each structural element of suspension bridges precisely. (2) The main cable of suspension bridge was a parabola curve in its initial construction state. Main cable turned into funicular curve when adding stiffening girder segments. The actual shapes of main cable depended on Sag/Span Ratio, sling separation, dead load of stiffening girder. (3) Along with construction stages stiffening girders were segment connected which increased vertical stiffness and vibration frequency of suspension bridge effectively. The dead load of stiffening girder at the same time could promote axial forces of main cable which greatly helped in resisting vibration of main cable and twisting of stiffening girder. (4) It is inferred by this paper that before closing stiffening girder, all stretches caused by temperature were absorbed by main cable, which caused larger displacement of tower top; conversely, after closing of stiffening girder, the stretches caused by temperature were absorbed by movable supports that connect bridge abutment and stiffening girder, therefore the displacement of tower top would not be interfered too much. (5) Linear changes of main cable during construction stage for both three-span and single-span suspension bridges would be interfered by central sag of side span main cables.The research results of this paper were expected to be references of Swing column suspension bridge nonlinear analysis and construction control.
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