Comparison Of Cable Force Schemes And Influence Analysis Of Closure Construction Of Cable-stayed Bridge With Single Tower Hybrid Girder

Due to its unique and novel shape,reasonable structural force performance and more economical advantages,the single-tower mixed girder cable-stayed bridge has become one of the more popular bridge structures in recent years.More research has been carried out by domestic and foreign scholars on the optimization of the cable force of single-tower cablestayed bridges and the analysis of the influencing factors in the completed bridge condition.In this bridge system,the bridge state obtained by different cable force optimization methods varies greatly,so it is crucial to study how to select the most suitable cable force scheme for the tower structure of the more special-shaped cable-stayed bridge to achieve a reasonable bridge state.The bridge closure is also a critical part of the construction process of cablestayed bridges,and studies have been conducted on the effects of the parameters in the completed bridge after closure.It is also important to analyze the influence of such special bridge types on the main girder line shape,internal forces and the degree of influence on the cable force under the influence of factors such as side span and main span girder forces,temporary loads/counterweights and temperature.And in this state whether to control the above factors have a greater impact on the closure,so it is necessary to carry out an in-depth analysis of these important key issues to summarize.By reviewing domestic and foreign information,this thesis takes Shaozhou Bridge as the engineering background,and after establishing the computational finite element model of the whole bridge,the specific research content is as follows:(1)It summarizes the principle of the mainstream rope force calculation method and the technique of the closure,and introduces the background of the project and the construction process of the closure.By modifying different constraint conditions and parameters,four different cable force calculation schemes are derived based on four types of cable force calculation theories.(2)After finite element analysis,the internal forces and line shapes of the main girders and main towers of the four cable force solutions are compared in the completed bridge condition and typical construction condition respectively.The relative optimal cable force solutions were obtained through screening.By changing the loading sequence of part of the second-phase constant load,the magnitude of the influence of the load sequence change is investigated.(3)To measure the influence of three parameters,namely,cable force,load and temperature,on the line shape of the internal force and the change of cable force of the main beam when the main span and the side span are combined twice.By monitoring the temperature and width of the joint opening,the law of the width change of the joint opening is summarized and the best time for jointing is selected,and the reasonable length of the jointed section is calculated to complete the accurate jointing.