Stochastic analysis of highway bridge isolated with tfp bearing system under spatially varying ground motion

The aim of this study is to identify of stochastic behaviors of isolated highway bridge with triple friction pendulum (TFP) bearing system subjected to spatially varying ground motion. Since the forces such as earthquake ground motion are random, it is impossible to estimate such forces beforehand. Therefore, it will be more realistic to perform the dynamic analyses of structural systems by means of stochastic analysis method which random forces are demonstrated in terms of averages and probability. In the stochastic analyses that were carried out, earthquake ground motion has been expressed with power spectral density function as a random transaction. Spatially varying effects of the ground motion includes the effects of wave passage, incoherence and site response. The fundamental period of isolated bridge with the TFP bearing system has been lengthened and energy absorption capacity of the structure has been increased with the effect of frictions in the isolation device. Therefore, there have been a significantly reduction in quastatic, dynamic and total response of the deck. As a result of the study, it has been emphasized that the TFP bearing system is substantially effective in stochastic behaviors of the structures having long span such as bridges subjected to spatially varying ground motion. In addition to this, even so element responses obtained from stochastic analysis of seismically isolated bridge have been significantly small values, the effects of wave passage, incoherency, site response should be taken into account in seismically isolated highway bridges.