Test And Optimization Of Cable Tension In Long-Span Cfst Tied-arch Railway Bridges

With the development of national economy, the domestic bridge career is also growing at a very rapid rate, especially bridges with cable structures which have been constructed a lot. Therefore, it has practical implications to the research of test the cable force and for some goal through optimizing the cable force.First of all, this paper has concluded the usual approaches to the cable force test. It has studied the principle of vibration-frequency measurement that has been widely used, and then has deduced the theoretical analysis formula of vibration method under the consideration of the factors like sag effect, flexural rigidity and boundary conditions. In addition, it has also summarized the practical formula for cable force calculation, and has proposed the deficiencies in the process of cable force test as well as the research requirements for the system of cable force test.Secondly, this paper has introduced the double influence matrix method, and elaborated the principles and the solution process, taking minimum bending strain energy and appointed stress states of arch ribs as optimum object separately. It has demonstrated the calculation formula and the counting process of double-influence matrix method, and also concluded the features of this method.Thirdly, a modeling for some1-96m concrete filled steel tubular tied-arch bridge in the Beijing-Shanghai high speed railway line has been given out. The bridge deck system has adopted grillage method for simulation. This paper has studied the real simulation of the suspender in modeling, the approximate treatment of arch rib section, and the parameter calculation of grillage method, and it has also discussed the influence of each parameter on the model result.Finally, this paper has given an introduction to the system components and the test process of vibration method for cable force test. Through acquiring the measured data under the finished bridge state, this thesis has contrasted it with the theoretical calculation data, and put forward suggestions for adjusting the force of cable. After applying the double influence matrix method to the optimization of the cable force, it can be found that the change for the smaller cable force value would result in the big change of moment value, and meanwhile, that the double influence matrix method has higher optimizing efficiency.