SEISMIC ISOLATION OF LONG SPAN AND SUPER LONG UNIT CONTINUOUS BEAM BRIDGE WITH FRICTION PENDULUM BEARINGS

Isolation using friction pendulum bearings is utilized in a long span and super-long unit prestressed concrete continuous girder bridge with a long period. A finite element model of the full bridge is established, and a bilinear hysteretic model is used to simulate the friction pendulum bearings. A nonlinear time history response analysis is carried out by inputting three safety evaluation seismic motions with 50-year 2% exceedance probability and seismic performance as verification. The results show that when the friction pendulum bearings have a curvature radius of 5m and a coefficient of sliding friction of 0.03, the piers and its pile foundations behave elastically. The maximum displacements of the bearing are 207mm and 198mm in the horizontal and transverse directions, respectively. The displacements can easily be accommodated by the gap. Long span and super-long unit continuous beam bridges with long period have their own structural features; friction pendulum bearings can effectively improve their seismic performance.