Construction Monitoring And Structural Performance Analysis Of Long Span Cable-stayed Bridge With Lower Tower

One of the most important requirements of railway bridges is rigidity.When the bridge span reaches a certain length,although the pre-stressed concrete girder bridge can meet the stiffness requirement,it's not economic enough.However,it is difficult for conventional cable-stayed bridge to find the optimal option for both rigidity and economy.To this problem,low tower cable-stayed bridges show some considerable advantages.At present,construction monitoring is basically mature in China.However,for railway low-stayed cable-stayed bridges,it is necessary to perfect control points in construction monitoring and analysis methods for on-site problems,which should be paid more attention by the monitoring and construction engineers.The single tension method has been widely used in China because of its small tension tonnage,small work surface required,and construction convenience.The "backward analysis method","formal analysis method",and "stressless cable length control method" are the main methods for determining the single root force,which are accurate enough but with complex solution process and high theoretical foundation requirements for construction technicians.Low-tower cable-stayed bridges can solve this problem well.On the one hand,they have large rigidity;on the other hand,some algorithms can be simplified,which is easier to be accepted by engineers.For large-span high-pier and high-rise railway cable-stayed bridges,the influences on structural performance from closure method and bridge piers height are nonnegligible,which need to be analysed more in the future because of the lack of researches.Based on the case study of Apeng River Bridge,the following steps are included in this research:1.The Midas/civil finite element software was used to model the bridge.Based on on-site situations,explained the problems in the actual monitoring process and corresponding solutions.2.Based on previous researches,simplified the method for calculating the single-strand pull force of parallel steel strands.Moreover,based on the catenary theory and the stress-free state control method,used Matlab to edits a program for calculating the cable force accurately.In addition,compared these two different calculation methods.3.Discussed the application scope of simplified single cable tensioning algorithm through control variate method and comparing with another conventional cable-stayed bridge.4.Analysed the linear variation of internal forces and main beam shape through comparing the influences on structural performance from different closing methods and pier heights.In the recent years,a great number of papers analysed the structural control and performance of the cable-stayed bridges with low levels.The aim of this research is providing a reference for the promotion of low tower cable-stayed bridge in China through analysing the construction process and structural performance of the Apeng River Bridge.