Novel Hidden Pounding Tuned Mass Damper for Vibration Control of a Cantilevered Traffic Signal Structure

Abstract

Traffic signal structures are very susceptible to wind-induced vibration because of their slenderness and low damping. In the wind, the vertical vibration is usually dominant, which affects driving safety and structural fatigue life. To suppress the vibration, a new type of pounding tuned mass damper (PTMD) is proposed in this study. It is specially designed for a cantilevered traffic signal structure with two improvements based on the original PTMD. First, the proposed PTMD has a hidden design and is housed inside the cantilevered mast arm of traffic signal structures, which can avoid visual interference and potential safety risks to drivers and pedestrians. Second, the static equilibrium position of PTMD is relocated so that its mass block just touches the lower boundary of mast arm, which makes it effective at any level of amplitude. Concretely, the mass block pounds the lower boundary of the mast arm under small-amplitude vibrations, while it pounds both the lower and upper boundaries under large-amplitude vibrations. The model experiment on a traffic signal structure was designed to verify the performance of the proposed PTMD in free and forced vibrations. Further, the corresponding numerical simulations were also carried out, where a nonlinear viscoelastic model was established to model the impact force and the related model parameters were obtained by the experimental results. Both numerical and experimental results show that the proposed PTMD is very effective in reducing the vibration of traffic signal structures.