Study On Sling Tensioning Optimization And Construction Control Technology Of Self-anchored Suspension Bridge

In this paper,how to optimize the suspension cable tensioning scheme of selfanchored suspension bridges,whether the self-anchored suspension bridges with symmetrical suspension cables can adopt the asymmetric tensioning process and determine the size of the asymmetric tensioning force,and whether the suspension cable extension can be used during construction The main research methods are based on the main cable shape analysis theory of suspension bridges,combined with engineering cases to conduct finite element simulation and analysis,and verify the feasibility of the optimization plan through construction monitoring methods.The main conclusions drawn are as follows:(1)A reasonable tension sequence is very beneficial to the safety of the structure and the economy of the project.By comparing the number of extension rods,the stress change range of the main beam,the number of cable saddle pushes,and the number of sling tensioning and other main control parameters for each scheme,it is concluded that "the middle span is stretched from the middle of the span to the two sides,and the side span is stretched from the side span direction to the middle span direction".This kind of tensioning scheme can reasonably meet the economy and safety of construction,so it is the optimal scheme.(2)The self-anchored suspension bridge is different from the ground-anchored suspension bridge in which the main beam is only a flexural member.The main beam is a flexural member.The axial compressive stress also increases gradually.By analyzing the stress change of the main girder in the optimal scheme,the boundary conditions that need to be changed are determined,that is,the main girder is lifted off the frame first in the mid-span area during the tensioning process,and the time to release the support support and the horizontal constraint of the permanent support is determined,so that the main beam can be freely deformed along the longitudinal and vertical directions of the bridge.(3)The selection of sling tensioning sequence and the control of sling tensioning force have a great influence on the stress of the structure.By analyzing the deformation of the main beam,the displacement of the main tower,and the change law of the cable force during the tensioning period,it is determined that the symmetry of the structure during construction is determined.Whether the suspension bridge can adopt asymmetric tension and the size of asymmetric tension,determine the appropriate time to increase the sling force to reduce the number of tension rounds.(4)The length of the construction period can greatly affect the economic investment.The less the number of tensions,the shorter the construction period.In order to verify whether the number of tensions can be reduced and the construction period can be shortened,after the system conversion is completed through dual control,the cable force is monitored and the position of the anchor point at the tension end is checked to determine whether the sling is properly tensioned.It was found that only individual slings needed to be pulled.(5)A reasonable bridge state can better meet the design life.Through the optimization of the main construction control parameters,the construction monitoring work is carried out on this basis,and the correlation between the monitoring results and the theoretical data is compared and analyzed,and it is verified that the two results are similar,and the error is within the control range of bridge construction.