Experimental Validation of a Double-Deck Track-Bridge System under Railway Traffic

This article describes the experimental and numerical evaluation of dynamic behaviour Cascalheira bridge, located on Northern Line Portuguese railway network. The bridge has a short span formed by two filler-beam half-decks, each one accommodating track. study includes development finite element model in ANSYS® software, as well situ characterization tests structure, namely ambient vibration tests, for estimation natural frequencies, modes shapes damping coefficients, test under traffic, particularly passage Alfa Pendular train. coefficients’ was performed based Prony method, which proved effective situations where classical methods (e.g., decrement logarithm) tend to fail, case mode with closed typically happens first vertical bending torsion modes. updating carried out using an iterative methodology genetic algorithm, allowing upgrade agreement between modal parameters. Particular attention given ballast degradation over longitudinal joint its influence global behavior this type double-deck bridges. Finally, validation comparing acceleration response structure traffic actions, means analyses considering vehicle-bridge interaction including track irregularities, ones obtained actions. results calibrated showed better accelerations evaluated several measurement points both half-decks. In process stiffness supports, demonstrated be relevant accuracy effectiveness models.