Dynamic soil-structure interaction of a single-span railway bridge, forced vibration testing and simulation

High-speed railway is expanding drastically in Sweden, necessitating new technology, and improvements of existing structures. End-shield bridges are a common and under-tested bridge type in Sweden. Their dynamic performance is significantly impacted by their boundary conditions due to the soil-structure interaction (SSI) and their large masses cantilevering beyond the footings. A specific end-shield bridge was tested under low (5 kN) and high (20 kN) amplitude-forced hydraulic excitation for a wide range of frequencies. Several train passages for typical passenger trains, 'X62', were measured with the same experimental setup. The results were analysed to isolate the significant modes of the system and the natural frequencies. A full 3D numerical model was calibrated and updated in Abaqus, along with a brief sensitivity study to determine the most influential parameters. Finally, the response to passing trains and Eurocode design HSLM trains was calculated. The experimental study showed that higher loading amplitudes resulted in higher damping and lower natural frequencies. The numerical analysis showed that for this bridge type the SSI cannot be neglected and can be successfully introduced in the model.