Vertical displacements of a steel-concrete superstructure, 51m long, under the Thalys train load, with speeds ranging between 1...110m/s.

Abstract

Objectives:
To determine the maximum deflections of the analyzed superstructure for the considered running speeds and to determine the critical speed that has as an effect the amplification of the vibrations and the increase of the deflections. The paper studies the behaviour of the superstructure from the point of view of the vertical displacements for the case in which the running track is straight (without counter deflection).
Work method:
The running track of the bridge has a special structure: the rails are continuously fixed into the concrete slab using the Edilon corkelast material.
In order to determine the impact of the increased speed upon the vibrations and deflections of a mixed section railway bridge superstructure, this superstructure has been carried into the SAP2000 finite element calculation programme.
Twelve non-linear dynamic analysis have been performed with the Thalys train that covers the analyzed model with speeds: 1, 10, 20...110m/s (3.6...396km/h).
Conclusions:
The paper analyses the vertical deformations of a railway bridge, steel-concrete composition, 50m span, under the action of a high speed train.
The critical running speed for the analyzed superstructure, train, and speed range is 70m/s (252 km/h). The maximum deflection has been recorded at this speed at midspan of the superstructure; its value was 23.10mm, higher than the 17.61mm deflection recorded at the speed of 110m/s (396km/h). Given that the amplification of the vibrations can appear also at the common running speeds of the high speed trains, we can state that a dynamic calculation similar to the one we have made here is recommended or even compulsory.