| Concrete-filled steel tubular (CFST) arch bridge is a new-type structure of bridge, which has been popularized and developed rapidly in the past ten years in China because of its advantage: light structure, beautiful model and super crossing ability. The study on design theories of CFST arch bridges gets relatively behind the engineering practice at present. The research on the creep and shrinkage of concrete, the temperature stress under the temperature load, dynamic performance under the traffic load of the structer need to be deepened.On the basis of a CFST tied rigid frame arch bridge, by means of general software ANSYS, a space finite element model (FEM) and a plane FEM are built to analyze its temperature stress and dynamic behavior under the traffic load with an emphasis on analyses of creep and shrinkage of concrete. The research of this paper includes mainly several parts:1 Considering the analysis of creep and shrinkage is a basic problem of bridge structure analysis. However, the research of creep and shrinkage of CFST is very limited. In this paper, the creep and shrinkage of frame tied CFST arch bridge is discussed. The analysis results reflect that the creep and shrinkage has a great influence upon the structure force and stress of any control cross-section. The cross-stress redistribution is very obviously. The creep and shrinkage of concrete has few influence upon the structure axial force, but has great influence upon the bending moment. This influence goes to be steady within two years after completing construction of the bridge.2 According to the CFST tied riged frame arch bridge, a plane computing model is built to analyze its temperature effect theoretically. The different design parameters such as ratio of rise to span, coefficient of arch axis and ratio of steel of the arc ribs have different influence on internal force, tress and displacement of any control cross-section of arch bridges. The results is calculated and compared. It reflect that changing the ratio of rise to span has obvious influence on the axes force under invariant load and on the internal force under temperature load of long span CFST arch bridges. The internal force and stress of arch bridge ribs can be decreased by increasing the ratio of rise to span in its design. Changing the coefficient of arch axis has a certain extent nonlinear influence on its bending moment and the axes forcewith temperature load by increasing the thickness of the steel tube can avoid tip of the arc being a focus of stress. The analyses results can provide the design of such type bridge with reference.3 The natural vibration and the time history dynamic response of the structure under different velocity moving load are analyzed on the basis of the space computing model. The analysis reflect that the dynamic response of the structure is very obviously under uniform velocity moving load, even if under a given fixate. So choosing the impact coefficient is very important in the design of such type bridge. |
