Impact absorbing damper to suppress bridge vibration at joints

摘要

Noise and vibration emit when a large lorry passes the expansion joints on road bridges, causingserious environmental problems. Field measurements were conducted on the road bridge, showingthat the dominant frequency was 13.3Hz when vehicles ran over the joints. A new type of damper,the impact absorbing damper based on momentum exchanging mechanism, has been proposed tosuppress the vibration occurred at the expansion joints. This damper system consists of the contactdevice between the RC slab and the additional mass with springs and oil dampers. When the vehiclewheel hits the expansion joints, the impact force is directly transferred to the attached mass throughthe contact device due to the momentum exchanging property, and then the energy produced byimpact forces are dissipated by the oil dampers. Parametric experimental studies were conductedusing a model consisting of the damper system and the RC slab which was impacted by a free-fallweight. The tests show optimum values of consisting elements of this damping system, such asmaterials of the contact device, mass ratio of the additional mass, damping ratio, spring constantsand impact forces. Then, the impact absorbing dampers were installed in an actual bridge, and itssuppression effect was measured. The model and field tests show that the new damper system isfeasible and effective in reducing the vibration and noise levels.