Dimensionless Continuum Model of Vertical Free Vibration of Spatial Self-anchored Suspension Bridge

Abstract

Due to the spatial coupling of main cable-hanger and the internal self-balance between subsystems, the free vibration continuum model of spatial self-anchored suspension bridge is difficult to establish, which limits the acquisition and identification of its dynamic characteristics. In this paper, the vertical free vibration continuum model considering hanger tension is established by integrating the vibration form deflection theory and the deformation and compatibility equation of main cable-hanger-beam, which is dimensionless to identify the characteristic parameters controlling dynamic characteristics; The shape function of main cable and girder satisfying the geometric and mechanical boundary is constructed, and the model is transformed into matrix form by Galerkin method to solve the modal frequency and vibration mode; Numerical examples and finite element models are used to verify the universality and accuracy of the continuum model, and the sensitivity of key stiffness characteristic parameters is analyzed. The results show that the relative elastic bending stiffness of the main girder significantly affects the modal frequency, and the elastic stiffness of the main cable only slightly affects the symmetrical modal frequency; The elastic axial stiffness of the hanger is sensitive to the relative elastic bending stiffness of the main girder. Whether the hanger tension is considered or not will significantly affect the high-order modal frequency, especially the antisymmetric mode. In conclusion, the continuum model considering hanger tension is more accurate, which can provide an effective reference for the preliminary design of the project and the real-time planning of dynamic disaster prevention and control scheme.