Effect of Bearing Damage on the Seismic Response of Girder Bridges

The hysteresis curve model was proposed to consider the bearing damage, the contact with the limitation device and the material nonlinearity. The calculation models of bearing, retainer were considered in the seismic response analysis. The results show that: (1) The bridge structure is unsafe under the action of large earthquakes without considering the friction effect of movable bearings. Because the friction of the movable support exists in the actual project, the structure of the first cycle of natural vibration on the weak field and considering the contribution of the movable support stiffness is closer to the field superior cycle of soil; (2) The limitation device restrains the beam displacement effectively, and reduces the seismic response of the fixed pier, and balances the distribution of seismic forces between the piers; (3) Under the conditions of large earthquake, when loss the sliding performance, the movable bearing will most likely result in the damage of piers. In the seismic design, a certain amount of rebar should be provided to ensure the ductility; (4) For different bridge structures, by changing the initial distance of the limitation device from the movable bearing, the rigidity and yield strength of the limiting device, and the coefficient and stiffness of bearing, the large displacement of the bearing could be prevent.