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PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros
Prediction of Structure-Borne Vibrations induced in a Large Structure by Train Passage
F. Braghin, S. Bruni and A. Collina
Department of Mechanical Engineering, Politecnico di Milano, Italy
F. Braghin, S. Bruni, A. Collina, "Prediction of Structure-Borne Vibrations induced in a Large Structure by Train Passage", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 47, 2009. doi:10.4203/ccp.91.47
Keywords: train-structure interaction, finite element-multibody co-simulation.
This paper presents a numerical approach for the prediction of train induced vibrations in large civil engineering structures. The procedure is based on the time domain simulation of train-track-structure interaction. The calculation is split into two stages to manage structure representations with a high number of degrees of freedom: in the first step, the dynamics of a train on the track and a simplified structure model is analysed; in the second one, the forces transmitted by the track system to the complete structure are used to analyse the transmission of vibrations inside the building.
A complete multibody vehicle model is combined with a complex finite element model of the track and the structure thus accounting for different scenarios. This proposed methodology can consider both the interaction between train and track and the influence of the structure on the track, while limiting the computational effort.
The development of a high speed railway system requires the consideration of major railway stations as the nodal points of the high speed network but also as exchange points with the regional and urban railway. Examples are the Berlin Hauptbahnhof or the Paris SNCF-RER-RATP network.
In Italy, an example is given by the widening of the main Bologna railway station, one of the main nodes of the Milan-Rome-Naples route, in conjunction with the realization of the loop rail connection which will enable the high speed line to pass through the downtown "Bologna Underground Railway Connection". The structure of the new Bologna station is divided into ten modules, each having a length of 60m, for a total length of 600m. It has three different floor levels below the railway station (ground) level: from the lowest floor to the top floor there is the "High Speed Platform (HSP)", the "High Speed Hall", the so called "Kiss & Ride" floor (devoted to shops and other commercial and social activities), the "FS Platform (FSP)" for ordinary trains at ground level, and above it the gallery level with a restaurant. Every 12m there is a transverse frame of horizontal beams and columns to which the different floors are connected. For this kind of structure both structure-borne and air borne noise problems originated from train transit are of relevance.
For the considered structure it is shown that traditional ballasted track is not able to reduce structure-borne vibrations down to the limits imposed by existing standards. A slab track, developed inside a EU founded project ("Hipertrack"), is instead able to significantly limit structure-borne vibrations and is therefore proposed to be applied for tracks that pass near or even inside large civil engineering structures.
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