The Suspender Force Optimization Of Through CFST Tied Arch Bridge

With the continuous improvement of materials,the bridge form of tied arch bridge is increasingly used in China.The advancement of science and technology,and the development of national economic also provide good support for it.Due to the special of external statically determinate and internal statically indeterminate form,the optimization calculation of the suspender force has always been a hot topic in the engineering field.The reasonable distribution of the suspension force directly affects the safe use of the bridge,especially the sudden rupture of the short suspender,which has been one of the important reasons for the tied arch bridge accident.Therefore,the research on the suspender force of the tied arch bridge is extremely important.In this paper,based on the 128 m tied arch bridge of Yinchuan to Wuzhong Passenger Line Yinchuan Nan grand bridge,optimization calculated the last stage suspender force and the initial suspender force.This article first consults relevant domestic and foreign literatures,to summarize the cable force calculation theory and major calculation methods of cable-stayed bridge and its application conditions,it is the theoretical support for the optimization calculation of the suspender force of tied arch bridges.After that,the finite element model of 128 m tied arch bridge of Yinchuan Nan grand Bridge was established,conduct final stage analysis and construction process analysis.The key contents are determination of the reasonable last stage suspender force,determination of the proper suspender tension order sequence and determination of the initial tension of suspender.The logic of this article is to obtain a reasonable bridge state first,then determine the order of suspender tension,and finally determine the initial tension of suspenders.In calculating the reasonable suspender force of the bridge,the suspender force of the tied arch bridge is calculated one by one by using a variety of cable force calculation methods for the cable-stayed bridge,and the calculation method unsuitable for the tied arch bridge structure form is expelled,after a variety of methods used in combination,the target suspender force was achieved.When determining the order of suspender tension,formulate four kinds of tensioning scheme,first use the retrograde analysis to obtain the initial tension of the suspender,then calculated according to the normal order,comparing the mechanical performance of the full bridge during construction,choose the optimal tension sequence.In this process,the disassembly simulation of the construction step of removing the support bracket is solved,and the data is closed well.In the calculation of the initial tension of the suspender,comparing the calculation resultsof iterative method and retrograde method,and examine the change in the suspender force during the construction of the suspender tension,finally achieved the ideal initial tension of the suspender.Through the optimization of the suspender force of the tied arch bridge,it is proved that the calculation method applied to the cable-stayed bridge is not fully applicable in the tied arch bridge,although both belong to the typical ternary structure,but the difference in structure determines the difference in calculation method.We can also conclude that it is difficult to obtain the ideal optimization result by a single calculation method,and the combination of multiple methods is more reasonable.In this paper,the calculation of suspender force of 128 m tied arch bridge of Yinchuan to Wuzhong Passenger Line Yinchuan Nan grand bridge is optimized through theoretical calculations.The research results have certain reference value for similar bridges.