Numerical Modelling of Building Vibrations due to Railway Traffic: Analysis of the Mitigation Capacity of a Wave Barrier (original) (raw)
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Study of the barriers for the mitigation of railway vibrations
The reduction of environmental interference caused by the passage of railway convoys at high speed, in recent years, has become a key element for optimization and approval of the design alternatives. Therefore the need to develop models which analyze the effects of the vibrations induced on buildings close to rail lines appears primary, in order to define and classify possible improvement choices. In this paper we analyze the problem of the propagation of vibrations in the ground and focus the attention on the dampening effect of a barrier placed between source and receiver, in particular, we model the phenomenon through the finite element method considering the presence in the ground of one or several discontinuities. A parametric study to investigate the importance of the position, for example, of the discontinuity, introduced by the membrane is performed; then, different numerical simulations are analyzed by changing the position, the dimension and the materials of the barrier in order to optimize the FE model in terms of stress agents on the foundations and to study how the wave propagation and the soil-structure interaction are influenced by the membrane which can be seen as a damping barrier.
Mitigation of Railway Traffic Induced Vibrations: The Influence of Barriers in Elastic Half-Space
Advances in Acoustics and Vibration, 2009
In this paper, the problem of vibrations induced by trains and their propagation through the soil is studied. Particular attention is focused on the vibration induced by trains in motion and on the effects of such vibrations on the foundations of buildings in proximity of the tracks. The interaction between propagating waves induced by trains in motion and buildings foundations is a problem which does not admit a straightforward analytical solution; thus a solution is given by the use of a model based on the finite elements method. Firstly, we analyze the theoretical aspects of the problem by considering constant or harmonic loads moving along a straight railway track; then, we define a transfer function soil-railway and the response function of the entire system. The study aims to address the wave propagation in an elastic semi-space and the presence in the ground of a discontinuity element, such as a barrier of a given depth is considered. The efficiency variation of barriers is analyzed in function of the different materials used, and different numerical simulations are analyzed in order to study how the wave propagation and the track-soil interaction are influenced by the membrane, seen as damping barrier.
Stiff Wave Barriers for the Mitigation of Railway Induced Vibrations
Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 2015
This paper studies the efficiency of stiff wave barriers for the mitigation of railway induced vibrations. Coupled finite element-boundary element models developed at KU Leuven and ISVR are employed; these models have been cross-validated within the EU FP7 project RIVAS [1]. A first mitigation measure consists of a block of stiffened soil included in a halfspace that acts as a wave impeding barrier. The existence of a critical frequency from which this mitigation measure starts to be effective, as well as a critical angle delimiting the area where the vibration levels are reduced, is demonstrated. Next, a sheet piling wall is considered, accounting for the orthotropic behaviour of this wall. Calculations show that the reduction of vibration levels is entirely due to the relatively high axial stiffness and vertical bending stiffness, while the longitudinal bending stiffness is too low to affect the transmission of vibrations. Field tests are being carried out in Spain and Sweden to confirm the conclusions of these numerical computations.
761. Study of wave barriers design for the mitigati on of railway ground vibrations
Journal of Vibroengineering, 2012
Nowadays, the consolidation of the rail in highly p opulated areas has become a reality. Foundations, buildings, high accuracy devi ces and people are susceptible to suffer from vibrations induced by passing trains. Therefore, mo dels for predicting ground vibrations are required in order to determine new mitigation measu res. Rectangular open or in-filled trenches are a suitable solution to be used near constructed railway lines. Their installation is fast, easy and economic since no intrusion in the track is nee ded. In this work, the influence of the trench design on its effectiveness is analyzed considering a train moving with subsonic speed. A finite element model of the track has been developed and validated with real data registered along the tram network in Alicante (Spain). The analysis is c arried out in the time domain considering the quasi-static movement of the vehicles. The results demonstrate that, in ascending order, the most relevant parameters in a trench are its w...
Vibration isolation of over-track buildings in a metro depot by using trackside wave barriers
Journal of Building Engineering, 2020
More and more cities consider to build superstructures over metro depots to comprehensively exploit the air space. However, metro train operations into and out of depots can generate excessive vibration and noise within the over-track buildings, which hampers the performance of vibration sensitive equipment and adversely affects the living quality of building occupants. This paper explores a systematic numerical investigation on the use of trackside wave barriers to isolate vibration transmission from the track into over-track buildings. A numerical model composed of a train-track dynamics sub-model and a track-soil-building finite element sub-model was developed to study the vibration isolation efficiency of various wave barriers including trenches and concrete walls. Utilizing this model, which was validated by previous field measurement results, parametric studies were further conducted to investigate the vibration isolation sensitivities of geometrical (depth, width and distance) and infilling material properties of trenches. Results showed that the open trenches performed best in building vibration isolation, and its isolation efficiency depended on the normalized depth. Geofoam trenches, i.e. soft material infilled trenches, were proved to be more effective than lightweight aggregate concrete trenches, i.e. hard material infilled trenches, in the dominant frequency range of 16-40 Hz. Concrete walls offered even worse vibration isolation performance than the hard material infilled trenches. These results can be used as a guideline in designing the geometry of wave barriers or the infilling materials of trenches in metro depots with over-track buildings.
MATEC Web of Conferences, 2018
This paper presents a selection of vibration measurement results and analyses performed with regard to their harmfulness to residential buildings. The first part of the paper refers to the analysis of railway vibrations measured in situ at the foundation level of residential building. These vibration records were then used to assess the harmfulness of vibrations relating to each train speed. Assessment of the vibration harmfulness of the building was performed with an indicator of the perceptibility of vibration through a structure (WODB), according to the Polish standard. The second part of the study refers to the creation of dynamic models of buildings with the use of the ‘Diana’ software program and analysis of their responses to railway vibrations. The thresholds specified by the standard in any of the train speeds of up to 250 km/h were not exceeded. Nevertheless, propagation of vibrations induced by train passages and their effect on the structural response of buildings is a c...
Numerical modelling of ground-borne noise and vibration in buildings due to surface rail traffic
Journal of Sound and Vibration, 2007
This paper deals with the numerical computation of the structural and acoustic response of a building to an incoming wave field generated by high-speed surface railway traffic. The source model consists of a moving vehicle on a longitudinally invariant track, coupled to a layered ground modelled with a boundary element formulation. The receiver model is based on a substructuring formulation and consists of a boundary element model of the soil and a finite element model of the structure. The acoustic response of the building's rooms is computed by means of a spectral finite element formulation. The paper investigates the structural and acoustic response of a multi-story portal frame office building up to a frequency of 150 Hz to the passage of a Thalys high-speed train at constant velocity. The isolation performance of three different vibration countermeasures: a floating-floor, a room-in-room, and base-isolation, are examined.
Journal of Vibroengineering, 2014
Railway-induced vibrations mitigation has become a priority issue in recent years. Among all the existing alternatives, wave barriers stand out because they can be implemented in any moment of the railway life span without interfering in the correct operation. However, limitations imposed by the track environment usually exist and may affect to the wave barriers design. In this paper the mitigation power of different types of trenches is studied using a 3D FEM model validated with real data. For this purpose, different scenarios are defined in order to assess the influence on the final vibration results of the location and the filling material, if exists. In any case, geometric limitations imposed by the track surrounding elements are taken into account. These limitations significantly hinder the search of the optimal solution.
Railway induced vibrations are an important source of annoyance in the built environment, causing malfunctioning of sensitive equipment and nuisance to people. Within the frame of the EU FP7 project RIVAS, mitigation measures on the transmission path between source (railway track) and receiver (surrounding buildings) have been investigated. This paper reports on the numerical and experimental study of stiff wave barriers as efficient vibration reduction measures. Numerical simulations have demonstrated that the wave impeding effect of such barriers depends on the stiffness contrast between the surrounding soil and the barrier, as well as on the barrier's depth. Findings from the numerical studies are verified by means of two field tests. In El Realengo (Spain), a continuous barrier has been created close to an existing railway track using overlapping jet grout columns, while a sheet pile wall has been installed along a track in Furet (Sweden). At both sites, geophysical and geotechnical tests were carried out prior to the installation of the mitigation measures for the determination of the dynamic soil characteristics. Measurements of train passages before and after installation of the barriers are compared to numerical simulations in order to assess the vibration reduction efficiency. In El Realengo, additional measurements have been performed at a reference site adjacent to the test site in order to correct for variations of track, train, and soil characteristics in time. It is shown that both barriers are effective and result in vibration reduction from 8 Hz (El Realengo) and 4 Hz (Furet) on, respectively; the largest reduction is obtained immediately behind the barriers. This ability to solve low frequency vibration problems is a unique feature compared to most other vibration mitigation measures for existing railway lines.