Fast simulation of railway bridge dynamics accounting for soil–structure interaction

Número especial Bulletin of Earthquake Engineering, Ag. 2021: S.I. : SOIL-STRUCTURE INTERACTION EFFECTS ON THE DYNAMICS OF STRUCTURES. // Artículo Open Access CCBY 4.0. Disponible online 3 agosto 2021A novel numerical methodology is presented to solve the dynamic response of railway bridges under the passage of running trains, considering soil–structure interaction. It is advantageous compared to alternative approaches because it permits, (i) consideration of complex geometries for the bridge and foundations, (ii) simulation of stratifed soils, and, (iii) solving the train-bridge dynamic problem at minimal computational cost. The approach uses sub-structuring to split the problem into two coupled interaction problems: the soil–foundation, and the soil–foundation–bridge systems. In the former, the foundation and surrounding soil are discretized with Finite Elements (FE), and padded with Perfectly Match Layers to avoid boundary refections. Considering this domain, the equivalent frequency dependent dynamic stifness and damping characteristics of the soil–foundation system are computed. For the second sub-system, the dynamic response of the structure under railway trafc is computed using a FE model with spring and dashpot elements at the support locations, which have the equivalent properties determined using the frst subsystem. This soil–foundation–bridge model is solved using complex modal superposition, considering the equivalent dynamic stifness and damping of the soil–foundation corresponding to each natural frequency. The proposed approach is then validated using both experimental measurements and an alternative Finite Element–Boundary Element (FE– BE) methodology. A strong match is found and the results discussedMinisterio de Ciencia, Innovación y Universidades PID2019-109622RBUniversidad de Sevilla US-126491Generalitat Valenciana AICO2019/175Centro Informático Científico de Andalucía (CICA