Studies On Cable Lifting Construction And Influencing Factors Of Long-Span CFST Arch Bridge

In recent years,the construction technology of cable hoisting has been widely used in the construction process of CFST arch bridge.To ensure the stability of the system and into the arch after the line can meet the predetermined line is the key to cable construction.In this paper,the Boligou bridge as the engineering background.The research on the cable force,the tower stability,the internal force stress and the deflection of the arch rib and the influence of the construction at the arch ribs are carried out in the process of cable hoisting construction control.The model of cable hoisting system of Boligou glass ditch bridge is established by using Midas civil finite element analysis software.The torque balance method and the finite element zero displacement method and the optimization influence matrix method are compared and calculated.This paper analyzes the rationality of the influence matrix method in calculating the cable tension force,and uses this method to solve the cable force of each hoisting section.Through the study of the stability of the tower,the stability of the tower under various stress conditions is analyzed.The calculated results can meet the requirements of the construction,and the stability coefficient,ie,the stability eigenvalue,is calculated by the buckling analysis.The calculation results show that the minimum stability coefficient of the tower is 10.75.It becomes unstable along the bridge when bridge lose stability.Therefore,the longitudinal stability of the bridge should be emphasized in the construction and the calculation results can provide reference for the practical project.The influence of the displacement of the tower on the linearity of the arch ribs is analyzed.The displacement change of the tower when the tower is deviated in the longitudinal direction is reflected in the deflection value of the arch ribs,and the deflection of the arch ribs is not taken into account Values for comparative analysis.The calculation results show that the deflection of the arch ribs is 1.75 cm when the influence of the tower deviation is not taken into account.Considering the influence of the tower deflection,the deformation of the arch is 2.32 cm when the arch ribs are closed.Compared with the measured value,the error when the tower deviation is not considered is 12.13% higher than the error when considering the tower offset.The influence of the tower offset on the deflection of the arch rib during the lifting process can not be neglected.Therefore,the tower offset is an important factor to consider when studying the nonlinear relationship between the displacement of the tower and the deflection of the arch rib.The influence of the longitudinal extension of the upper and lower chord on the adjacent two sections during the construction of the upper and lower chord is analyzed.The difference between the longitudinal elongation of the segment end and the elongation of the upper and lower chords is analyzed,And calculate the offset value of the docking angle.The results show that the larger the temperature difference between the upper and lower chords is,the larger the difference between the elongation and the butt angle is.Especially in the lifting of the closure of the dock when the collision is relatively large.The change trend of the angle difference between the docking angle and the temperature difference is calculated,which can provide some reference for the analysis of the similar bridge.