Analytical study on flutter suppression by eccentric mass method on FEM model of long-span suspension bridge

A method of suppression of flutter in long-span bridges based on the concep t of eccentric mass is presented in this paper. The auxiliary mass is place d on the windward side of a bridge deck to shift the center of gravity, and thus, the aerodynamic moment acting on the deck is reduced, resulting in a n increase in the flutter wind speed. The state-space model of aerodynamic forces on the bridge deck section with eccentric mass is derived through a rational function approximation of unsteady aerodynamics. The parameters of the rational function model of a section of the bridge are obtained from t he flutter derivatives experimentally determined. Then, the FEM model of fu ll suspension bridge with main span of 2500 m is derived. It is shown from numerical study that addition of an eccentric mass gives a significant impr ovement in the flutter wind speed. Distributing the eccentric mass in the c enter-span is found to be the most effective. (C) 2001 Elsevier Science Ltd . All rights reserved.