Analysis Of Extradosed Continuous-cable-stayed Bridges With Main Girder String Structure

Extradosed continuous-cable-stayed bridge with main girder string structure is a new style, which combines the character of extradosed cable-stayed bridge and main girder string structure. It has many merits, such as rationality of structural arrangements, good mechanical behavior, powerful ability to span, wind and fatigue resistance, and so on. It is a breakthrough and development over traditional extradosed cable-stayed bridges. It makes full use of the cable’s efficiency so that the cable not only has the ability of supporting the main girder as the traditional extradosed cable-stayed bridge, but also brings about an additional stiffness of the main beam to improve the stiffness of the whole structure. Since the ability of the cable and beam cooperation is better than that of the traditional extradosed cable-stayed bridge, the style has a good prospect. As one innovative style, there are no researches and projects about its structural performance, so this dissertation does analyse this style and gets some characteristics including the following aspects.Firstly, introduce the development and classification of extradosed cable-stayed bridges and main girder string structure, then describe the basic concept and do the conceptual analysis of this new system.Next, discuss the innovative forms of cable-girder anchorage for extradosed cable-stayed bridges. A series of models are created by use of the software ANSYS, including single-cable models, simplified models and multi-cable models. The effects of such parameters as location of web members, the height of web members and the string sag ratio are discussed.Then, referring to one practical project as prototype, analyze the models with the same cable collocation types of initial structure. Adjust the parameter values (the height of beam, cross section and the height of web members) to get theappropriate range of parameter values of extradosed continuous-cable-stayed bridges with main girder string structure.Finally, based on the practical project, get the structures with different ranges of cable collocation, analyze mechanical performance of the new style, and explore the advantages of extradosed continuous-cable-stayed bridges with main girder string structure.