A practical longitudinal buckling analysis method of spatial diamond-shaped pylon cable-stayed bridge

The stability performance is a crucial factor when designing cable-stayed bridges. In addition, spatial diamond-shaped pylon is a novel pylon type applied in bridge engineering. Therefore, the stability analysis of spatial diamond-shaped pylon cable-stayed bridge is of great research value. In this paper, a practical longitudinal buckling analysis method is developed based on energy approach. The possible longitudinal buckling of the top pylon column, the mid pylon columns, and the girder are all considered in the proposed method. The total potential energy of spatial diamond-shaped pylon, girder, and cables is calculated. Then, the buckling coefficients and buckling modes are obtained by the principle of stationary potential energy. The Changtai Yangtze River Bridge is taken as an example, and the accuracy of the proposed method is verified by comparing the results with those of the finite element method. Furthermore, a parametric study is conducted to confirm the applicability of the proposed method. Design parameters, including the stiffness distribution of the structure and the inclination angle of the mid pylon column, are varied. Finally, the appropriate degrees of polynomial functions when hypothesizing buckling modes of different components are discussed.