Study on bridge flutter suppression by control surfaces on FEM model of control system

In this paper a passive aerodynamic control by additional control surfaces attached beneath the bridge deck is studied. Motion of the control surfaces is related to the pitching motion of the deck through additional pendulum. The time domain model of unsteady aerodynamic forces is obtained through the rational function approximation of experimentally determined flutter derivatives of flat box bridge girder. The rational model shows good agreement with the experimental results obtained on sectional model of the passive aerodynamic control system. The numerical analysis of full FEM model of the suspension bridge with control surfaces indicates that the surfaces should be located in the mid span of the bridge and the sufficient length of surfaces is about 30% of the length of the main span.