Design and analysis of friction pendulum bearings for seismic mitigation and isolation of long span continuous steel truss girder bridge

To improve the seismic performance of long span continuous steel truss girder bridge, the main bridge with span arrangement (102+4×168+102) m of the Changqing Huanghe River Bridge in Ji'nan was cited as an example and in the light of the structural features of the bridge, the friction pendulum bearings were selected for the design of the schemes of whole bridge seismic isolation and continuous pier seismic isolation for the bridge. The spatial finite element model of the bridge was set up by the universal program SAP2000, the model was excited by three artificial seismic waves and the structural responses of the bridge that was not seismically isolated and that was seismically isolated by the friction pendulum bearings were analyzed and compared by the nonlinearity time-history analysis method. The results of the analysis indicate that the friction pendulum bearings for both the schemes of whole bridge seismic isolation and continuous pier seismic isolation can achieve good effect of the seismic mitigation and isolation and can meet the design requirements. As compared to the scheme of whole bridge seismic isolation, the moment of the pier footings and the horizontal displacement of the bearings in the scheme of continuous pier seismic isolation are slightly great, but the scheme is more economic. In comprehensive consideration of several factors of the seismic mitigation and isolation effect, economy and dimensions of the bearings, it is recommended that the friction pendulum bearings with 4 m equivalent sliding radii for the scheme of continuous pier seismic isolation should be adopted for the seismic mitigation and isolation design of the bridge. ©, 2015, Wuhan Bridge Research Institute. All right reserved.