Hybrid fluid-dynamic control devices to attenuate slender structures oscillations

In the present work, a hybrid fluid-dynamic control system is proposed for the active/passive control of bending oscillations of tall and slender buildings under wind forces. The mathematical-numerical model of the hybrid system is developed from the classical tuned liquid column damper composed of one or more “ U ” tubes filled with fluid. When in motion the control system generates hydraulic forces which counteract the inertia forces induced by the dynamic loadings acting on the structure. Some of the main design aspects, dynamic properties and the resulting performance of the proposed hybrid control system as compared to those of the traditional liquid columns and tuned mass dampers for passive control are presented and discussed with the aid of the results obtained by using both analytical and FEM models together with comparisons between the uncontrolled and controlled responses of the structure having attached the proposed hybrid fluid-dynamic devices. Two examples of a practical application are presented to demonstrate the feasibility and performance of the hybrid control device in attenuating the bending oscillation amplitudes of slender structures of tall buildings under wind forces.