Computational modeling of a mixed-material railway bridge using soil-structure interaction

Resumo

This study presents the development of a parametric geometry model and computational modeling strategies for a steel-concrete composite railway bridge located in Brazil. The asset features a reinforced concrete deck with a total width of six meters and a variable deck thickness ranging from 30 cm to 35 cm. A parametric model was implemented using the Rhinoceros/Grasshopper environment. Custom routines in GiD were developed to automate the finite element mesh generation, assign the material properties, and incorporate loads and boundary conditions into the model. Following this preprocessing stage, the model was integrated into CSiBridge platform to perform dynamic analyses and evaluate the railway bridge performance under service conditions. The bridge dynamic behavior was assessed through onboard monitoring techniques, which recorded train-induced responses during regular operation. A time-history dynamic analysis, coupled with influence surfaces, was conducted considering soil-structure interaction models applied to the railway bridge foundations. The computational model was then calibrated using experimental dynamic responses. Additionally, the wheel load information extracted during the monitoring campaign was incorporated into the simulations. The analyses identified the vibration modes and natural frequencies of the concrete components of the asset. Finally, a comparison between experimental and computational responses is presented, providing a foundation for future resilience studies of the railway bridge.