Time-Domain Analysis of Galloping of Main Cables of Suspension Bridge during Erection Process

In order to analyze the galloping instabilities of main cables, the quasi-steady aerodynamic force formula was derived in a body axial coordinate system to avoid the coordinate transformation of aerodynamic coefficients in a wind axial coordinate system in the existing galloping analysis methods. As a result, a more concise galloping criterion expression was obtained. A simplified finite element model for main cables of a suspension bridge was established to analyze the structural dynamic characteristics. And aerodynamic coefficient curves of main cables with different cross-sectional shapes during construction were obtained by the CFD (computational fluid dynamics) method. Finally, based on the time-domain analysis method, a single-degree-of-freedom model for galloping and a three-degree-of-freedom model for galloping were respectively used to simulate the wind-induced galloping of main cables. The research results show that the galloping critical wind velocity obtained by the single-degree-of-freedom model for galloping is good consistent with the theoretical result, and the three-degree-of-freedom model for galloping can reflect the real galloping performance of main cables much better.