Construction Control Research Of Long-Span Concrete Filled Steel Tubular Arch Bridges

In this paper, research work is concentrated on the construction control theory of concrete filled steel tubular (CFST) long-span arch bridges. On the background of the scientific research items about long-span concrete filled steel tubular arch bridges: the NAMO great bridge(190m, finished building in Jun,2003) and the Shijiadu Lijiang River Bridge(200m, finished building in Nov,2003), a complete analysis theory and calculation method for concrete filled steel tubular arch bridges which include normal service time and construction control are presented. The main subjects are summarized as follow:1. In this paper , a method of Spline element combining ANSYS is presented for the solution of the structural analysis of the concrete filled still tubular arch bridges. With thw cubic B spline function treated as displacements, the spline element stiffness matrix is established based on the principle of minimum potential energy. With the help of the secondary development function of ANSYS, a famous finite element program, the spline element is established in ANSYS as a user element, and the structure calculation is made using the pre and pro process function and equation solver. At last, analysis of the construction processes of the NAMO Great Bridge and the Shijiadu Lijiang River Bridge are made using the method of Spline element combining ANSYS, and the results can be considered b> the constructurors.2. The stability of the construction process in every period is analysis using the method spline element combining the ANSYS. The characteristic of oblique-draw-buckle-hanged by jack construction system is discussed which is used in the construction of concrete-filled-still-tube(CFST) arch bridge. The stability and safety of the constructionyprocess of Namo Bridge is analysis and its coefficients are got, consideringthe changing load and structure, using nonlinear program ANSYS. And the result can be considered to choose the erection projection.3. The limit load capacity of the Lijiang River Bridge is calculated based on the bi-nonlinear theoty, with the use of APDL language(the program technology of ANSYS) to add initial defection to bridge structure. And the results were referenced by structor.4. The optimization theory and method is used to calculate the cable forces and the prearranged height of the CFST arch bridges. This method solves the problems of the times and the methodological restrict adjusting cables force in the new construction technology for diagonal fastening and connecting by use of jacks and cables.5. The method of gray system combining artificial neural net (G-BP) is introduced into the construction control of CFST arch bridges for the first time. The error of the construction process is analysis with this method, and the forecast list of the prearranged height is adjust according to the analysis results.