Table 2 shows the highest response of the displacements and strains obtained from a few sensors during the speed test. Table 3 shows the dynamic magnification factors computed for displacements and strains for different sensors and for different speeds. This factor is computed as the ratio of maximum dynamic displacement/strain to the corresponding component under a quasi-static moving load. It is seen from Table 3 that the maximum amplification factor is 1.0487 for displacement, and this occurs at the crown of Span 2 for Formation 1 moving from CR to K at a speed of 30 km/h. For strains, the maximum amplification is 1.68 for the tangential component at the crown of Span 1 for the Formation 1 moving from K to CR at a speed of 20 and 40 km/h. This indicates that the crown experiences the highest amplification of strains, and this is further augmented because of the steep gradient in elevation and curvature in the plan of the arch. Further, the amplification factors do not appear to change significantly with a change in speed. This suggests that the bridge mass is substantially higher than the train masses, reducing their interactive effects.
Read More: http://ascelibrary.org/doi/full/10.1061/%28ASCE%29BE.1943-5592.0000338