To analyze the performance of trains running on structures when an earthquake occurs, the RTRI has improved the conventional Dynamic Interaction Analysis for Shinkansen Trains and Railway Structures (DIASTARS) program that has been used to discuss dynamic loads on structures and the running performance of trains under normal conditions. This has made it possible to consider wheel climbing on rails, the non-linearity of springs and dampers between car body, truck frame and wheel-set, the non-linear hysteresis of bridge piers and other structural elements in the analysis of running train performance. It is now possible, therefore, to analyze in detail the vibration of structures and the behavior of rolling stock when an earthquake occurs. The program also makes it possible to model the profile of the bent angle between structures that is eased by the track through application of an interpolating function. This enables effective analysis of structures that are several kilometers long.
      The program also allows analysis of the behavior of train-sets running on adjacent structures when an earthquake occurs, taking into account the difference in the arrival time of seismic motion at different points (Fig. 1). It has also clarified that, where plural bent angles occur on adjacent structures subjected to seismic motion, the critical structural displacement governing the limit of running safety decreases according to the degree of bent angle and train speed (Fig. 2).

Fig. 1 Analysis of adjacent structures vibrating in different phases due to differing arrival times of seismic motion

Fig. 2 Effect of the bent angle between structures on the critical displacement governing the limit of running safety when an earthquake occurs

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