Galloping analysis of the main cable in construction: An advanced nonlinear scheme

Abstract

The main cables of suspension bridges in construction are non-circular sections and thus prone to galloping vibrations. The traditional galloping analysis is a linear scheme and cannot address the nonlinearities and coupling effects among the multidirectional vibrations. To provide an approach for the nonlinear galloping, this paper proposes an advanced continuum model based on Hamilton's principle and variational calculus, which can systemically consider the translational and rotational vibrations and the nonlinearities from the geometric, damping and wind effects. On this basis, the computational approach for the continuum model in COMSOL Multiphysics is investigated, and the result comparisons between the proposed approach and finite element method indicate that the continuum model together with the computational approach can accurately determine the dynamic responses of the main cable. When the quasi-steady based wind forces are included, the nonlinear model can be easily used for galloping analysis, and the limit cycle oscillations (LCOs) in the post-instability of the adopted example are obtained, which are the typical nonlinear aeroelastic phenomena for bluff bodies. Also, the obtained frequency evolution of the LCOs is discussed.