Parametric flutter analysis of bridges stabilized with eccentric wings

Abstract

The eccentric-wing flutter stabilizer is a passive aerodynamic device for raising the flutter speed of a bridge. It consists of wings running parallel to the bridge deck. In contrast to similar devices proposed in the past, the wings do not move relative to the bridge deck and they are positioned outboard the bridge deck to achieve a greater lateral eccentricity. This enables the wings to produce enough aerodynamic damping to effectively raise the flutter speed. A comprehensive parametric flutter analysis study is presented in which both the properties of the bridge and the configuration of the wings are varied. The bridge properties and the wing configuration are each summarized in four non-dimensional quantities. The parameter space within which these numbers are varied are determined on the basis of previous work and the structural properties of actual long-span bridges. As for the wind forces, a streamlined bridge deck contour is assumed. The main interest of this study is the relative flutter speed increase due to the wings. This and other non-dimensional results are presented in diagrams and discussed. Both multi-degree-of-freedom and generalized two-degree-of-freedom flutter analyses are performed. Torsional divergence is addressed. A strategy for choosing a cost-efficient wing configuration is suggested.