| With the development of Arch bridge in China's High-speed Railway construction,the Concrete-filled steel tubular arch bridge of Nelson system is popular in railway construction,due to its overall rigidity,beautiful appearance,good economic efficiency,safe and reliable,superior ability and so on.In order to avoid the structural collapse and other major accidents in the process of the bridge construction,to ensure the quality of structural construction,and to achieve the perfect design intent as far as possible,construction monitoring by the third party is proposed by the state-related departments in the construction of Bridge with high technical content.The construction monitoring of domestic and outer bridge is mostly for large span cable-stayed bridge? continuous rigid frame bridge and so on,and there is a lack of systematic and targeted construction monitoring technology measures and construction practice,which is specifically aiming at the construction monitoring of Nelson's CFST Arch Bridge.The origin and development of Nielsen concrete-filled steel tubular arch bridge is described,and the characteristics of the arch bridge is introduced.The article takes the actual engineering as the background,mainly makes the following research and summary:1.The simulation model of three-dimensional bar structure is established by using finite element software Midas/civil,and the construction phase of all bridge is simulated,at the same time,the modeling method of key structure of arch bridge is summarized in detail.2.A comprehensive construction monitoring scheme is compiled,and the technical key points of measurement and monitoring are introduced.In particular,the new technical means of stent monitoring is introduced,which ensures the structural safety of the main girder casting support system.3.The error estimation of the control parameters is carried out by using the least squares principle that combined with the flip-chip analysis method.Through the example analysis,the recognition is compared between the true value of parameters and the parameters to be iterative correction.After the original design parameters are iteratively modified,higher accuracy of parameter estimation is got.Therefore,In the process of construction,through the parameter identification correction,the actual project of the forecasting model can be established to better guide the construction in an orderly manner;4.On the basis of the more accurate calculation model,the flip-flop method and the influence matrix method are used to compute the initial tension of the boom.The calculation principle and process of the two methods are introduced in detail.Taking the design of the boom cable force as target and taking into account the deformation and internal forces of the structure are proposed in two methods.The application of the two methods in different tensioning schemes reveals that the combination of the influence matrix method and the iterative analysis has a greater advantage in computing the initial boom tensioning.5.According to the sequence of different boom tensioning,the influence matrix method combined with the iterative analysis is used to calculate the reasonable initial tension of the boom,and then the fitting analysis is carried out.The boom tensioning scheme is selected by analysis and research,which conforms to the actual and easy-to-implement.In this paper,through the study of the construction monitoring of Nielsen concrete-filled steel tubular arch bridge,the theoretical basis of the bridge is provided which arch bridge construction state is closer to the design state.Which provides empirical guidance for the construction monitoring of the same type arch bridge. |
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