A Damper System for Mitigation of Suspension Bridge Flutter

A floating system using a continuous girder between two anchor blocks is often adapted for increasing the span length of suspension bridges. The flutter instability of the floating system due to winds is thus of great critical interest. This paper proposes a new control system to mitigate the flutter of the floating-type suspension bridge. The proposed control system consists of vertical dampers installed between the pylons and the bridge deck. The linear evaluation model is developed using the equations of motion generated around the deformed equilibrium position. Using the analytical model, performance of the proposed control systems is studied and compared to a traditional system with joints at the pylons. It is shown that the proposed control system improves the overall stiffness and stability of the bridge. A control strategy using semi-active or active dampers is also proposed to enhance the controllability of the floating-type suspension bridge against flutter instability.