Research Of Reasonable Completion State Of Cable-stayed Bridge Considering The Construction Process

Cable-stayed bridge is one of the most widely-used types of modern bridges. It is a kindof highly redundant and complicated structure,which is composed of the tower, girder andcable.the cable only stands the pulling force, the tower and the girder is pressure-curvedcomponent that primarily take on pressure, and the cable tensions have greatly tremendousinfluence on the distribution of internal stress in the structure system and they have becomethe key to control the internal forces of the whole bridge. The final structural state is directlyaffected by construction stages.One of the keyproblem about design and constructiontechnology of cable-stayed bridge is how to optimize cable force to the rationao distributionof internal stress in the structure system and how to determine the rational construction stateto achieve the target of dead load state in design.In view of the above problem,this paper putsforward the comprehensive method to optimize cable force on the basis of the stress-balancemethod and also determine reasonable reasonable construction state by the unstressed statemethod. The dissertation is divided into three parts below according to its structure andcontent:Part I:On the basis of all kinds of cable-stayed bridge design data for reference, thispaper summariesmodern cable-stayed bridge static design calculation process and points outthat the problem of determination of reasonable completion state and reasonable constructionstate is the most critical.On the basis of previous study for cable force optimaztion,this paperintroduces five kinds of practical methods about cable force optimaztion and review them.Then the calculation of reasonable construction stages by method of assemble iteration andinverted-disassemble is explained and compared to the Theory of unstressed state controlmethod. Part II: This paper summaries evaluation principles of reasonable completion state oncable-stayed bridges.On the basis of the minimum bending energy method, the stress-balancemethod, the influence matrix method and two planning theory, the paper put forward atechnological process of comprehensive method. then, take the actual project as an example,give initial cable force, optimize the cable force. And this method has a great applicationvalue. Part III:The theory of unstressed state control method and the definition of elements’unstressed state are explained in detail. Finally the reliability of unstressed state controlmethod is verified in steel cable-stayed bridge. The no-closure phenomenon is explained.Based on a concrete cable-stayed bridges example, the no-closure phenomenon of forwardcalculation is solved by unstressed state method.