Influences of train speed and concrete Young's modulus on random responses of a 3D train-track-girder-pier coupled system investigated by using PEM

In this paper, a refined three-dimensional (3D) vibration model for a train-track-girder-pier coupled system is established and solved using a pseudo-excitation method (PEM). Considering the excitation of random track irregularities, a high-speed railway case study is presented to verify the effectiveness of the model and the method by comparing the results with those given by a Monte Carlo method. A pre-stressed concrete box girder for a high-speed railway bridge with excitation of random track irregularities is used to investigate the influences of train speed and concrete Young's modulus on the random dynamic responses of the coupled system. The results show that the PEM is 1-2 orders of magnitude more computationally efficient for the random dynamic analysis of the train-track-girder-pier systems compared with the Monte Carlo method. The power spectral densities (PSDs) of vertical accelerations of coach body change only slightly with time, but they change significantly with track irregularity frequency. All the first peaks of the PSD curves for the coach body vertical acceleration are shown to appear at around the same fundamental frequency. The concrete Young's modulus of the girder has a large influence on the PSDs of the vertical acceleration of the bridge, but the distribution of vibration energy in the frequency domain varies very little. The results can be applied to railway design and maintenance.