Cable Force Optimization And Construction Simulation Analysis Of Extradosed Cable-stayed Bridge

Cable-stayed bridge is a kind of high-order statically indeterminate structure.Conventional finite element and numerical methods have low efficiency and accuracy in the optimization of cable force using single point successive calculation,and the internal force of the optimized bridge is not ideal.Genetic algorithm has the ability of parallel calculation and global search,which can effectively solve these problems.However,compared with Extradosed Cable-Stayed Bridge,the main girder of low-pylon cable-stayed Bridges usually adopts variable height prestressed concrete structure,and the cable-free area near the side span and tower root is longer.The above characteristics are not taken into account when the cable force optimization of the completed bridge is carried out by ordinary genetic algorithm,and the cable force is uneven after solving.In order to improve the Extradosed Cable-Stayed Bridge completed bridge optimization calculation efficiency,at the same time make a optimized into a state of bridge more reasonable,based on genetic algorithm,to join the elite retention mechanism and the cable force of variance as constraint conditions,cable force optimization method was proposed based on improved genetic algorithm,combined with a Extradosed Cable-Stayed Bridge under construction in dongguan to completed bridge optimization verify the feasibility of this method,The main work contents are as follows:(1)Summarize the current cable force optimization theory of Extradosed Cable-Stayed Bridge,and based on the stress characteristics of low pylon cable-stayed bridge,propose the cable force optimization method of Extradosed Cable-Stayed Bridge based on improved genetic algorithm.(2)The cable force optimization method based on improved genetic algorithm is used to optimize the cable force of a Extradosed Cable-Stayed Bridge under construction in Dongguan city.Compared with the finite element method,the optimization efficiency of the improved genetic algorithm is higher,the positive and negative bending moments after optimization are reduced by 9.9% and 5.6% respectively,and the internal force of the bridge is more reasonable.Compared with the common genetic algorithm,the improved genetic algorithm has little change in the internal force of the optimized bridge,but the convergence speed is faster and the cable force distribution is more uniform.(3)Taking the cable force optimized by the improved genetic algorithm as the target cable force,the initial tension was solved by the normal assembly analysis to guide the construction,and the cable stress,girder stress and line shape were simulated and analyzed.The maximum cable stress in the construction process was 627.40 MPa,and the cable stress safety factor was2.96.The maximum compressive stress of the main girder is 14.48 MPa,and the maximum deformation of the main girder after the completion of the bridge is 228 mm,which meets the safety requirements.