PSI - Issue 84

Lorenzo Sangiuliano et al. / Procedia Structural Integrity 84 (2026) 1326–1333

1332

Figure 4: comparison between experimental (black) and theoretical (in blue with 8-car ETR500Y), speed 260 km/h

Figure 5 : comparison between experimental (square points) and theoretical (in blue). To the left ETR500Y 12 carriages and to the right ETR500Y 8 carriages

3.4. 3.4 Extension of results to different train speeds To test the potentialities of the workflow, the train speed was varied in order to evaluate the evolution of the Dynamic Coefficient, defined as the ratio between the displacement under moving load and the displacement under static conditions. A total of seven analyses were carried out. Once the computational code was set up, the bridge modelling required only a few seconds, the FEM analysis approximately 2–3 minutes, and the subsequent post-processing about an additional 3 minutes. The span lengths considered were: 20, 30, 40, 42.5 (original), 50, 60, and 70 m. From the plots, as shown in Figure 6, it can be observed that the abscissa reports the train speed, while the ordinate shows the corresponding dynamic coefficient. The 50 m span configuration exhibits the highest amplification among all cases, with a coefficient close to 2. Another noteworthy observation concerns the dependence of the dynamic coefficient on the span length: for a given speed, the dynamic coefficient varies significantly with span length and, as expected, tends to increase as the span becomes longer, with the exception of train speeds in the range of 100–200 km/h (Figure 7).