Mechanical Behavior Analysis Of Construction Process Of Nelson System Arch Bridges

In recent years,China has developed rapidly in the structural design and construction of bridges.A large number of long-span bridges with complicated structure and creative form have emerged.The concrete-filled steel tubular tied arch bridge of Nelson System is one of them.The construction technology of concrete-filled steel tubular tied arch bridge with Nelson system is various and its process is complicated.Therefore,it is very important to study the key technology of monitoring and rational construction of the bridge in order to meet its design criteria and make the construction state close to the ideal state.In this dissertation,the construction process,the stability analysis and the cable force optimization analysis of the concrete-filled steel tubular tied arch bridge of Nelson system are studied,based on the construction of the bottom-through concrete-filled steel tube tie-bar arch bridge of Xue jialong,Huaihua city,Hunan province.This dissertation includes the following major study and conclusions:1.According to the structure and field construction technology of Xue jialong bridge,the calculation model of the finite element analysis is established.The finite element program is used to analyze the bridge construction process and to analyze the mechanical performance of the bridge structure,which provides the theoretical basis for the stress and displacement development of the bridge under various construction conditions.2.A finite element calculation model is established,starting from the structure of the internal force,deformation,stress,dynamic performance and stability,the comparative analysis of the Nelson system tied arch bridge with vertical arch bridge suspender system,summarizes the structure characteristics and advantages and disadvantages of the system of Nelson tied arch bridge,and provide a theoretical basis for the practical application of Nelson system of arch bridge.3.The space finite element analysis model,considering the hanger tension of the space interaction,to internal force,displacement and stress and stability as the control target,determine the reasonable hanger tensioning order,calculation of the bridge hanger target state of bridge cable force by rigid hanger method calculation,and of construction stages the influence matrix method,the optimization of the bridge construction,the bridge,the proposed guidance for the bridge construction.4.Establish space finite element analysis model,the spatial stability of Nelson arch bridge during the completion and construction is studied.The overall stability of bridge structure under various load conditions is analyzed,and the reasonable construction state of the bridge is defined.The calculation and measurement results of this dissertation have been applied in the actual construction control of the bridge,which met the design requirements and achieve the expected research objectives.