Determination Of Reasonable Completion Status And Sensitivity Analysis Of Structural Parameters For Self-Anchored Suspension Bridges

The self-anchored suspension bridge has the graceful aesthetics,so it becomes the best choice for urban bridge.The structural parameters of self-anchored suspension bridges have different effects on the structural mechanical properties.The geometric nonlinearity has a great influence on the process of bridge construction.The internal forces and structural alignment of the completed bridge basically cannot be adjusted after the complex system transformation.Therefore,it has important engineering application to carry out the determination of initial equilibrium state and the influence analysis of different structural parameters on the mechanical performance of the self-anchored suspension bridge.The main contents of this dissertation are as follows:(1)The recursive-iterative calculation method of the conformation analysis of the main cable of suspension bridge was introduced.A method for finding the main cable shape considering the slanting sling was proposed.Recursive-iterative calculation methods were widely used in cable-shape analysis.For the plane and spatial cable systems,the E-M iterative algorithm and Steffens-Newton iterative algorithm were used to modify the control variables in the recursive calculation process respectively.The plane cable and spatial cable shape-finding program for suspension bridges was programmed by using MATLAB software.The calculation process of the main cable shape of the spatial cable suspension bridge considering the the slanting sling was proposed.And the correction algorithm of control variables in recursive computing was introduced.(2)The method for determining hanger cable force of reasonable completed bridge state was proposed.The idea of temperature correct the unstressed length of cable unit was recommend.The temperature of the cable unit can be updated iteratively based on the influence matrix method until the optimal goal of structural alignment was met.The cable force in this state was the reasonable hinger cable force.The feasibility and efficiency of the method were verified by an engineering example analysis.And the method of forming the influence matrix and the optimization steps of the hanger force were given.(3)A calculation method for determining the initial equilibrium state of self-anchored suspension bridge was proposed.Based on the reasonable hanger cable force,the key finite element modeling parameters such as main cable node coordinates,main cable and sling unit non-stress length were obtained by using the self-made suspension cable-type cable shape finding program.Then,MIDAS/CIVIL was used to establish the finite element model.The initial equilibrium state of the self-anchored suspension bridge was finally obtained through the accurate analysis.(4)The influences of structural parameters on the static performance of the bridge were analyzed.Keeping the other parameters unchange,the influence sensitivity on the internal force and displacement of the bridge was obtained by the whole process analysis mode.