ABSTRACT
ABSTRACT: Before commissioning and after some time of commercial service on the Belgian sectionof the high-speed line fromParis toBrussels, the actual train car accelerationsweremeasured by a special test train. Close analysis of the measured values enabled to compare to predicted values. The measurements show in general 30% lower values of the predicted maximum amplitude of instantaneous accelerations. In addition, the measurements allowed verifying experimentally the galloping movements of trains crossing longer viaducts. This galloping may show a resonance frequency, increasing fundamentally the cyclic angular rotation about a horizontal axis of train cars. Fourier-analysis of the peak values of accelerations allows the definition of a resonance number. The main influence factor for this phenomenon is the ratio of the train speed to the individual span of the viaduct. The results of measurements were also compared to international recommendations. This comparison suggests that the recommendations are insufficient for long span bridges and 300 km/h high-speed bridges. Several steel arch bridges have been tested on fullscale level for stress concentrations in main elements and in orthotropic plated decks. The tests show that continuous measurement of stresses is indispensable for obtaining all peak values. In addition, the tests have revealed that, due to the ballast, the stress variations from railway loading are considerably lower than for road traffic. This demonstrates that steel orthotropic plated decks are a solution, which is particularly well adapted to railway traffic. At present, the development of the High-Speed network is reaching its final stage in Belgium and already new line extensions are being prepared. Various designs for these extensions are shown and explained in this paper.
