Development of steel dampers for bridges

Bridges using fixed connections between girders and piers sustained significant damages in destructive earthquakes, leading to a search for alternatives having better seismic performances. New connections combining isolation bearings and dampers are becoming popular in recent bridge engineering practice. This paper presents a new type of steel damper for the bridges. The new steel dampers are able to overcome the defects of the conventional ones which could not sustain large displacement demands required for the bridges. The proposed damper utilizes steel plates as the energy dissipation components and adopts a vertical free mechanism to allow large deformation. Physical tests using quasi-static cyclic loading are conducted to investigate the damper´s seismic behavior. Test results suggest that the new dampers have stable hysteresis behavior under large displacements.