EFFECTIVENESS OF WAVE PASSAGE EFFECT OF SEISMIC ISOLATED AND NONISOLATED BRIDGES UNDER SPATIALLY VARYING GROUND MOTION

In this study, stochastic analyses of isolated and nonisolated highway bridges under spatially varying ground motion are performed. The bridge is isolated with triple concave friction pendulum (TCFP) bearing. The selected bridge is assumed to be constructed on homogeneous soft soil. Incoherency effects are neglected and wave passage effect is taken into account in the stochastic analyses. The bridge model subjected to spatially varying earthquake ground motions in the horizontal direction. The horizontal input is assumed to travel across the bridge from left to right side with finite velocities of 100m/s, 200m/s and 400m/s. The means of the maximum responses of displacement and internal forces of bridge deck are investigated. The results of these stochastic analyses are also compared with the results of infinite velocity. Analysis results show that using TCFP bearing on Highway Bridge reduces means of maximum values of total axial force, shear force and bending moment of bridge deck by 89%, 86% and 96%, respectively. In generally, low speed is more effective than high speed at the means of the maximum responses of internal forces of bridge deck. The finite velocity is the most effective at means of the maximum responses of horizontal displacement of bridge deck.