Vehicle-induced vibration mitigation of bridges with stiffness degeneration by pounding tuned mass dampers

A cracked bridge with reduced stiffness is susceptible to vehicle-induced vibrations above the warning threshold. This study proposes a pounding tuned mass damper (PTMD) with an adjustable mass and double pounding boundaries covered with a viscoelastic material. The PTMD is intended to reduce bridge vibrations caused by vehicle loads. A vehicle-bridge-PTMD coupled equation of motion is established against the engineering background of a continuous steel-concrete composite girder bridge. The bridge performance degradation is evaluated in terms of crack density and stiffness reduction coefficient, which are determined through field crack investigations. The vehicle-induced vibrations of a cracked continuous steel-concrete bridge are then studied while changing the parameters of the designed PTMD. The PTMD effectively reduced the vehicle-induced vibrations of the bridge. The vibration reduction ratio reached 38.9% after applying three PTMDs with a total mass ratio of 2%. On a simply supported steel-concrete composite beam, three PTMDs with a total mass ratio of 2% reduced the vibration amplitudes by 31.4%.