Mejora de la respuesta dinámica transversal de un viaducto alto frente a la acción del tren y del viento

Abstract

When a high speed train cross a high pier bridge under the action of a lateral turbulent wind, the risk of overturning increases. Besides, this wind excites several lateral vibration modes of the bridge and therefore the traffic safety worsens. Previous works show that with the use of wind barriers, the risk of overturning practically disappears. Nevertheless, the dynamic bridge response increase then, because the structure has more surfaces exposed to the wind. In this paper, improvements in the train and bridge behaviour due to the use of tuned mass dampers have been studied by means of numerical simulations. In the study, the bridge has wind barriers and is subjected to turbulent wind. And the damper devices are situated over the pier heads for the simulations. A dynamic interaction model of the train-bridge-wind system was developed for this study and for previous others. In that model, a three-dimensional multi-body train with 23 degree of freedom per vehicle and a finite element bridge system are considered. For reproducing the interaction between wheel and rail, a simplified contact model has been included which considers the whole wheel and rail profiles, with the wheel flange. Track irregularities are also taken into account. This model is able to simulate the relative lateral displacement between the wheel-set and the track in a suitable way. The model and its code developed have been checked by comparison of results with cases solved in scientific literature which employ simpler models. The mechanic properties of an articulated train type AVE-Alston (or Thalys) with 10 vehicles have been used in this study. As example of high pier viaduct with wind barriers O’Eixo viaduct has been chosen. This structure is situated in the Orense-Santiago high speed railway line in Galicia (Spain). It has 80 m. high piers, a length of 1224 m. and a natural (lateral) vibration frequency of 0.23 Hz. The observed results show improvement in the bridge response due to the tuned mass dampers employed in the pier heads of the viaduct. In this way, the bridge meets better the requirement of the serviceability limit states increasing the traffic safety.