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CivilComp Proceedings
ISSN 17593433 CCP: 99
PROCEEDINGS OF THE ELEVENTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY Edited by: B.H.V. Topping
Paper 174
Train Induced Free Field Vibrations Experimental and Numerical Analysis J. Bencat and M. Škarupa
Department of Structural Mechanics, Faculty of Civil Engineering, University of Zilina, Slovakia , "Train Induced Free Field Vibrations Experimental and Numerical Analysis", in B.H.V. Topping, (Editor), "Proceedings of the Eleventh International Conference on Computational Structures Technology", CivilComp Press, Stirlingshire, UK, Paper 174, 2012. doi:10.4203/ccp.99.174
Keywords: microtremor, railway traffic effects on structures, prediction, dynamic half space models, structure response models, in situ experimental tests, ground vibration, structure response spectra, spectral analysis.
Summary
A numericalexperimental model for the calculation of groundborne vibrations arising from railway traffic is introduced. The calculation procedures for the freefield dynamic response at a distant point (from the railway track) using spectral analysis with experimental input data are described. In the numerical model the soils are modelled as a viscoelastic halfspace [1,2].
In the numericalexperimental model (NEM) experimentally measured soil vibration data near the railway track is used as an input data into viscoelastic halfspace. The freefield vibration at the distance prediction is calculated using a spectral analysis procedure. In this model procedure, it is suggested that a soil medium transfer function, elastic and attenuation soil parameters from the experimental in situ test (impactseismic method  ISM) are applied. Then the halfspace output data (output PSD) at a distance are calculated using the standard spectral analysis procedure [3]. The use of the random process theory to predict the level of ground vibration in the vicinity of railways using the calculation of the spectrum of vibration at a halfspace point are possible by using two principal ways: (i) using a computer implementation of the theoretical expression for the rail roughness spectrum, the vehicle mass distribution spectrum and a model of vehicle dynamics and tracksoil interaction and the frequency response function (FRF) of the ground by a method involving integral transform, (ii) using an average response force spectrum derived from experimental data for the authorized railway category with a corresponding track profile and the frequency response function of the ground and to calculate the response spectrum vibration at a point in the same way as mentioned in (i). The random process theory in the investigation of the dynamic ground properties can be utilized as well. Using the input signal (due to traffic) the measurement in the ground and the output signal measurement passing through the ground, frequency response function, elastic and attenuation characteristics of the ground can be obtained [1]. To provide a case study of the ground vibration and the transmission from a railway the experimental tests were carried out adjacent to the ZSR railway Bratislava  Vienna track No. 1. The ground vibration frequencies were obtained using spectral analysis of the recorded soil response dynamic components, which are considered ergodic and stationary. Spectral analysis was performed using the software package NI LabVIEW. References
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