Study On The Manufacturing Dimensions Of Main Girders And Reasonable Construction State Of The Super-large Span Hybrid Beam Cable Stayed Bridge

When the hybrid beam cable-stayed bridge enters the super-large span,the geometric nonlinear effect is an influencing factor that must be considered.This article takes Hubei Jiayu Yangtze River Highway Bridge as the engineering background,Based on the theory of stress-free configuration,The nonlinear forward iteration method determines the manufacturing dimensions of the main beam and the reasonable construction state is deeply studied.The calculation formula for installing the line shape to calculate the unstressed line shape is derived.Taking the unstressed length of stay cable as the control condition,Reasonable construction status of cable-stayed bridge is determined.The main research contents and related achievements are as follows:(1)According to the geometric nonlinearity of super-large span cable-stayed Bridges,The basic idea of the stress-free configuration control method is introduced,The geometric nonlinear effects of structures are discussed,The iterative solution of the installation line shape and the correction method of the installation line shape in the iterative process are studied.(2)The calculation method for calculating the unstressed line shape from the segment-by-segment installation line is deduced:The required installation line is obtained by using the nonlinear forward fitting iterative method,Based on the unstressed relationship between the installed beam section and the beam section to be installed,The unstressed line shape of the main beam is calculated by the installation line shape.Geometric nonlinear effects and concrete shrinkage and creep effects are fully considered in the iterative process.This method is successfully applied in the determination of the manufacturing dimensions of the steel box girder of Jiayu Yangtze River Highway Bridge.The results show that:The method can accurately solve the unstressed linear shape of the main beam,The calculation results can meet the steel box beam manufacturing requirements.(3)Solving construction control tension based on the unstressed length of stay cable:Design line shape as a bridge target,Taking the unstressed cable length as the control parameter,The new unstressed length of stay cable is calculated from the design cable force and the current bridge line shape after each iteration.The iterative calculation stops after obtaining a set of construction control tensions that are designed to be in the bridge state.This method is applied in the whole process analysis of Jiayu Yangtze River Highway Bridge construction.The results show that:This method can simplify the solving process of controlling tension force in cable-stayed bridge construction,save the time of trial calculation in the solving process,and has higher calculation accuracy.(4)Analysis of the whole process of super-long span cable-stayed bridge construction based on stress-free configuration theory,The height of the beam segment is determined,The influence of the difference in the shrinkage of the top and bottom welds on the positioning elevation is discussed.The structural response of the construction process is analyzed.