Study On Construction Control Of Special-Shape Concrete-Filled Steel Tubular Arch Bridge

With the rapid development of economy in China, increasingly importance has been attached to bridge aesthetics. Therefore, a large number of beautiful special-shaped concrete-filled steel tubular (CFST) arch bridges spring up in recent years. However, with the advent of special-shaped CFST arch bridge, the structural system becomes more and more complex, and the stiffness of the special-shaped arch rib is constantly changing in the construction process, thus the construction problem is also more prominent.Based on practical project—Dadu He Bridge, this thesis is mainly concentrated on the half-through special-shape CFST arch bridge for construction and linear control, the displacement and stress in pouring process, the concrete shrinkage and creep analysis and the structure stability and so on.1. The existing construction methods of CFST arch bridge is summarized and the selection of the reasonable arch axis and the influencing factors are analysed in this thesis. And two ways to control the line of arch rib are also proposed in this thesis. One is to calculate the lofting length of the arch rib; the other is to set camber for the arch rib. By applying the finite element analysis software to set up the actual bridge model, the measures of the linear control of the Dadu He Bridge are discussed in the thesis, and the construction process is analyzed in detail. Then the different tension sequences of the suspender are adopted in the thesis to analyze the influences to the structural stress and displacement in the service phase and construction.2. The main parameters of the pumped concrete mixture ratio are analyzed and the derivation of the pumping pressure calculation formula is also given in this thesis. Through the simulation of pumped concrete process and the core concrete stiffness forming process, the influence of the internal force, deformation, stability and stress redistribution of Dadu He Bridge are discussed in this thesis.3. In the thesis, the computing models, the basic theory and the characteristics of shrinkage and creep of the core concrete are elaborated in detail. Using the core concrete creep coefficient formula of the previous derivation and the creep coefficient in the Road and Bridge Specifications, the influence that the core concrete shrinkage and creep have on the Dadu He Bridge internal force and displacement are discussed in this thesis. Through the analysis, a conclusion that the displacement and internal force due to shrinkage and creep hardly change after three years is drawn in this thesis.4. A detailed study is carried out on the stability theory and methods of analysis of CFST arch bridge, and then the buckling analysis of Dadu He Bridge is conducted in this thesis. Through the analysis in the thesis, the stability coefficients calculated in the construction and service phase meet the requirements of the specifications. And then this thesis analyzes the impact on the stability in detail, such as the side arch and its inclination, transverse brace and diagonal bracing, the invalid suspender and side cable. The conclusions of this thesis provide references for the similar bridges.