| Cable-stayed bridges have become the first choice for large-span bridges in recent years because of their beautiful shapes and reasonable stress on the overall structure.The pylon is the basic load-bearing component and important component of the cable-stayed bridge.It not only bears the weight of the main beam bridge deck system transferred by the self-weight and the cable stay,but also bears the vertical load and horizontal load caused by the bridge deck system.Bending moment.The structure and stress state of the tower are relatively complicated.The tower column itself is affected by external environmental factors such as external force,temperature,wind,etc.The resulting swing and displacement deformation damage the structure of the tower and affect the cable-stayed bridge into a linear shape.It will also endanger the safety of the bridge.Therefore,it is necessary to strictly control the construction process of the tower.This article takes a twin-tower cable-stayed bridge under construction in the southeast coast as the research object,and monitors the entire construction process of two towers and analyzes the sensitivity of construction parameters.The main research contents of this article are as follows:(1)The finite element software Midas Civil was used to establish the numerical models of the two towers respectively.By studying the stress state of the tower under the two construction methods,it was concluded that the stress state of the tower is more reasonable when the synchronous construction method is used.The combination of theoretical calculation and numerical simulation was used to calculate the temporary transverse bracing force of the tower,and the cross-sectional strength and stability of the temporary bracing under the most unfavorable load combination were checked and analyzed.(2)Through the calculation and analysis of the finite element model of the cable tower and the full bridge,the theoretical settlement value of the cable tower under various working conditions is obtained,and the pre-elevation value of the lower beam is determined by the theoretical settlement value of the cable tower.Through the monitoring and analysis of the environmental temperature and the pylon temperature on the construction site,the variation law of the pylon temperature and the ambient temperature is obtained.The environmental temperature difference is used to predict the temperature difference of the pylon and the influence of the temperature stress on the pylon is eliminated.(3)The Midas CFD software was used to calculate the aerodynamic parameters of the position of the bridge tower,the wind effect of the bridge tower was simulated,and the static three-component force coefficient and aerodynamic derivative of the section of the tower were obtained.At the same time,the Midas Civil is used to calculate the tower under the wind load,and the stress,displacement and bending moment values of the tower under the wind load are obtained,which provides a reference for construction monitoring.(4)Based on engineering examples,select the tower concrete bulk density,concrete elastic modulus,climbing form load value,temporary tie rod force,temporary tie rod application position,temporary transverse bracing force,temporary transverse brace applying position and temperature as the tower structure sensitivity Analyze the parameters and perform sensitivity analysis on the cross-section stress and displacement of the tower.Temporary tie rod force,temporary tie rod position,temporary transverse brace force,temporary transverse brace applied position,and temperature are significant effects of the tower’s control section stress and lateral displacement of the tower,as the tower’s sensitivity parameters;concrete bulk density,concrete elastic modulus The amount and climbing mode load have little effect on the control section stress and lateral displacement of the tower,which is a non-sensitive parameter of the tower. |
PDF Full Text Request