Research on Soft Flutter of 420m-Span Pedestrian Suspension Bridge and Its Aerodynamic Measures

Abstract

In order to study the flutter of long-span pedestrian suspension bridge and its aerodynamic control, a 420m-span pedestrian suspension bridge is used as an engineering example, the wind-induced vibration of seven particular aerodynamic sections is studied by wind tunnel tests, and the soft flutter phenomenon of two kinds of aerodynamic sections is identified. The results show that the wind fairing and the wind-retaining plate measures are not necessarily effective measures to improve the wind-induced stability of long-span pedestrian suspension bridge, as these two measures may reduce the flutter stability: the wind fairing section in the positive angle of attack is prone to torsion-based soft flutter phenomenon, in which the vertical vibration spectrum contains multiple vibration frequencies, so the conventional formulation of the linearized self-excited forces is no longer satisfied; the wind-retaining plate section in the negative angle of attack is prone to soft flutter dominated by vertical vibration, and the beat vibration phenomenon is found in the torsional vibration time history of the wind-retaining section. Slotting in the center of the girder section can significantly change the flow state of the section, which is an effective measure to improve the flutter stability of the pedestrian suspension bridge.

Coupled Flutter Behavior and Mechanism of Flexible Suspended Footbridge

“…Research has also been conducted to improve the flutter stability of footbridges. Guan, Liu, Gao, Wang and Li [4] experimentally investigated the effect of aerodynamic vibration control devices such as twin decks, fairing, and wind-retaining plates on the flutter wind speed. However, limitations in attaching these devices to flexible suspended footbridges have been pointed out [5].…”

Validity of Galerkin Method at Beam’s Nonlinear Vibrations of the Single Mode with the Initial Curvature

“…However, it is very complicated for the finite-terms Galerkin discrete model or the direct perturbation method to obtain the solutions for the nonlinear equations. In fact, the most convenient and effective method of solving the mechanical problems of continuous structures is the finite element method [30][31][32][33][34][35][36]. This method is widely used in static and dynamic problems of structures [33][34][35][36].…”