PSI - Issue 84

Gian Felice Giaccu et al. / Procedia Structural Integrity 84 (2026) 1055–1062

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(c) Fig. 6. Time histories for Section Model 1 in the controlled case ( ≠0 rad/s): (a) mean wind tunnel speed , (b) deck pitch angle , and (c) gyroscope angular velocity . 3.5. Experimental Flutter Observations with active Gyroscope (Model 2) This subsection presents the results for Section Model 2, with key findings shown in Fig. 7 below. The experiment was conducted at a constant flow speed above the critical flutter velocity of the uncontrolled case, while the gyroscopic device was progressively activated by adjusting the input voltage to the motors. The corresponding variation of the stabilizer’s angular velocity is shown in Fig. 7(c). The results confirm the stabilizer’s effectiveness: control of deck instability is noticeable at =60 rad/s (steady state), and the time history demonstrates a gradual increase in stabilization, similar to Section Model 1. 4. Conclusions This paper presented wind tunnel experimental results, assessing the feasibility of a gyroscopic stabilizer installed under a long-span bridge deck to mitigate flutter. A section model of a truss-type bridge deck, replicating the main features of the Golden Gate Bridge, was tested at Northeastern University’s wind tunnel. The main findings are: • The prototype effectively mitigates flutter and increases the critical flutter velocity. • Different operational regimes confirmed the stabilizer’s performance under realistic aerodynamic load conditions. • Both section models, each equipped with different stabilizers, showed improved deck performance, with gyricity enhancing stability even under variable gyricity. For full-scale applications, the stabilizer’s mechanical properties must comply with the bridge design, potentially using multi-unit absorbers installed at specific cross-sections along the deck and compatible with commercial gyroscope specifications ( , Ω ). Future research will optimize the design parameters of the stabilizer, including effects of mass eccentricity and the potential use of this device to reduce buffeting-induced vibrations below flutter threshold.