The Determination Of The Reasonable Bridge State And Construction Process Simulation Of Cable-stayed Bridge

Cable-stayed bridge is a kind of high statically indeterminate bridge,is a kind of structural system which is made up of bridge towers, girders and cables.The internal force of cable decied that of the tower and girder,Once the cable force change, the line shape and the internal force of the tower and girderwlii also change. According to the diffrent criterion of final bridge, we could find a group of stayed-cable forces. So the determination of reasonable stauts of finished bridge is equivalent to finding a group of cable tension,making the force state and the line shape confirm the design standard. Large span cable-stayed bridge is ordinarily made with cantilever construction process, before the midspan fold, cable-stayed bridge is always in the double cantilever state, during the period, construction load has been changed, the boundary conditions change, structure system has also transformed. the geometric nonlinearity of the structure is more noticeable, construction sequence related to the internal force and the linear shap of bridge,at the same time,in order to ensure the safety of construction, the cable-stayed bridge construction stage must be analyzed carefully.The paper's background is gaoyou cable-stayed bridge in jiangsu province,using the finite element analyzing software Midas to build the analyzing model,doing the deep research on the reasonable finished state and the cable tension during the period of construction.The first and second chapter briefly describes the structure characteristics of the cable-stayed bridge and development condition and development prospects in recent years, and introduce the nonlinear characteristics of long-span structure.The secong chapter is mainly introducing the nonliner factors of Cable-stayed bridge, including the cable sag effect, the mutual influence between bending moment and axial force, and large displacement effect.and several solutions of nonlinear structure are introduced late.The third chapter introduces the principal and varities of methods of determining the reasonable finished-bridge state, including zero displacement method, minimum bending strain energy method, the synthetic method. at last,we find the most reasonable method is the synthetic method,which could consider the live load and dead load effect together, make the top and bottom flange stress of the stiffening girder section less than the allowed stress of material.The last chapter introduces the method of analysising the construction process and compare the advantages and disadvantages each other. The method of calculating the construction cable force is also introduced,including the difference method and iterative method.Considering the Jie Shou cable-stayed bridge as engineering background, the two kinds of forward calculation are used to get the tensile cable forces of the construction process, gain a finished bridge state under the control of the former forces and compare the internal force staus of the tower,the girders,and the cables.Finally, the paper analysis and compare the influence of different nonlinear factors on the cable force of the completed bridge later.