Simulation Analysis Of The Songao Bridge's Stability And Dynamic Performance

The concrete-filled steel tube (CFST) Truss TI LAN-type arches improve the lateral stability by sloping the arch rib, it is often used in the designs of CFST arch bridge with small ratio of the width to the span. SongAo CFST arch bridge is a symmetric half-through ecardinate arch, the structure of arch rib adopts flat-faced truss form. Based on the design feature of this bridge, the stability buckling and natural vibration feature are analyzed in the paper.The paper introduces development and present situation of the CFST arch bridge firstly. Base on the summary of the arches bridge's advantage, the current study conditions of stability and dynamic characteristics are analyzed in details in the paper. Then the basic theories and solution methods of CFST arch bridge are further introduced.The software ANSYS is used to analyze the linear buckling, the geometry nonlinear buckling combining with the characteristics and mechanical research findings of this bridge. In order to consider the nonlinear behavior of material, the stress-strain relationship of concrete filled steel-tube structure is introduced in the following research. The analysis result shows that the stability factor of the bridge is bigger in the linear and elastic condition, while the value of the stability coefficient only decreased a little when taking into account geometrical non-linearity. But when the geometrical non-linearity and material non-linearity are all considered, the value of the stability coefficient greatly decreased. It also shows that the instability of CFST arch bridge almost happens in the plastic area, and stress of the instability is bigger than the high-pointed of the elastic stress. The stability factor will be very bigger if the linear method is used in analyzing the stability of the bridge. So the ultimate loading is exact only when we consider the geometrical non-linearity and material non-linearity.Due to CFST arch bridge has characteristics of large deformation and large strain, stability of this bridge is computed through considering geometrical non-linearity, the analysis result shows that lateral direction and vertical direction displacement of arch rib is large. However, after considering both geometrical non-linearity and material non-linearity, lateral direction and vertical direction displacement of arch rib is greatly decreased. Therefore, when designing this type bridge, the maximum displacement under geometrical non-linearity and material non-linearity analyzing should be taken as reference.Besides, taking the example of SongAo CFST arch bridge, firstly, natural vibration feature and effects of the structure construction on natural vibration feature are analyzed. The structure construction includes mainly five factors here, which are thickness of steel tube, steel tube diameter, wale disposal, supporting condition, and so on. These factors analysis provide some theoretical guide.