SEISMIC RUNNING SAFETY OF RAILWAY ROLLING STOCK ON CONTINUOUS GIRDER BRIDGES WITH SEISMIC ISOLATION BEARING

Abstract

The purpose of this paper is to clarify the running safety of railway rolling stock during earthquakes when the bearings of continuous girder bridges are seismically isolated in the direction perpendicular to the bridge axis. Dynamic interacion analyses between vehicles and structures revealed that a derailment limit input acceleration of vehicles running on a continuous bridge decreases in the center span of the continuous girder when the natural frequency of the pier is 2 Hz, whereas it tends to decreases at the structural boundary on the exit side due to the occurrence of angular rotation when the natural frequency of the pier is 0.5 Hz or the dominant frequency of the track surface decreases due to the seismic isolation. By designing seismic isolation bearings with a yield seismic intensity of 0.4 and a predominant frequency of the track surface of 0.5 Hz or less, derailment can be prevented even for the L2 seismic earthequake class. When seismic isolation bearings satisfying these conditions are implemented into continuous girder, the horizontal displacement of the track surface does not increase significantly, and the horizontal displacement of the pier top can be reduced by to 50%.