In this paper, a numerical model was first established based on satisfactory predictions of the dynamic characteristics of a seismically isolated bridge under ambient vibration conditions and the seismic performance of the bridge under the 1022 Gia-Yi earthquake. Then, parametric studies of the bridge model under simulated near-fault ground motions are carried out to investigate the near-fault effect on this bridge. Results indicate that near-fault amplifies the seismic response of this base isolated bridge when the pulse period is close to its effective period. The amplification decreases as the pulse period becomes larger than the effective period for the simulated Type-A ground motions. However, the near-fault effect may be significant even the pulse period is much larger than the effective period for the simulated Type-B ground motions. Additional observations from this study include the ratio of dissipated energy by the lead-rubber bearings to the total input energy, which can be somewhat influenced by the near-fault effect.
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