Study On Several Design Parameters Of Curve Extradosde Cable-stayed Bridge

Extradosed cable-stayed bridge is the transitional type of bridges between continuousrigid frame bridge(or continuous beam bridge) and the traditional cable-stayed bridge. If themain beam stiffness, the mechanical properties of the structure showed nearly continuousrigid frame bridge, on the contrary, structural mechanical properties close to the traditionalcable-stayed bridge. Curve extradosed cable-stayed bridge able to adapt to the mountainousterrain and the linear route requirements. For mountainous areas the possibility ofconstruction traditional cable-stayed bridge which’s the curve radius greater than300m issmall, so the small span extradosed cable-stayed bridge has a great advantage.This article is to study on several design parameters of the curve extradosed cable-stayedbridge. In order to provide the basis and reference for the preliminary design of the curveextradosed cable-stayed bridge in the future.1. This article firstly elaborated the origin, development and trends of the extradosedcable-stayed bridge, and research status of the non-cable area length, single and double cableplanes applicability and the long-term deflection conducted a detailed investigation.Summarized the existing four methods of defined in extradosed cable-stayed bridge. Learnfrom the formulation of the type A and B partial prestressed concrete, proposed a newcategory name of the extradosed bridge that is type A and type B extradosed cable-stayedbridge.2. The arrangement type of extradosed cable-stayed bridge single and double cableplanes do research through the facade of the cable plane and transverse layout. And analysisedstructure stressing influence with tower stiffness and curve radius change of the curveextradosed cable-stayed bridge which is single or double cable planes. In the preliminarydesign of the curve extradosed cable-stayed bridge, the single cable plane and double cableplanes as design parameters, without considering of the impact of the radius of the curve.Double cable planes compared to a single cable plane to improve the torsional behavior of thestructure is not obvious, and the twin towers column to improve the cost, so single cable plane arranged on the economy has more advantages.3. Through cable arrangement length, cable arrangement location and non-cable arealength, researched cable-stayed layout design of the curve extradosed cable-stayed bridge.Non-cable area length of tower root improve the structural performance is obvious comparedto non-cable area length of side span and mid-span, so adjusting non-cable area length oftower root as measures to improve the structural performance in the design. Non-cable arealength of side span and mid-span impact the maximum torsional moment of main girder isobvious compared to non-cable area length of tower root.Non-cable area length of tower rootshould be controlled in (0.16~0.35)L, non-cable area length of mid-span should be controlledin (0.06~0.25)L, relevant non-cable area length of side span in (0.05~0.16)L(L is the length ofmain span).4. Repeated loading, prestress loss, cable-stayed initial tension and concrete shrinkageand creep as the main factors of long-term deflection of cross-bridge structure. Analysis ofthe impact of various factors on the long-term structural deflection and obtain various factorsto time course of changes in the law.