TY - CONF A1 - Auersch, Lutz T1 - The excitation, propagation, and mitigation of train-induced ground vibrations from the axle impulses on the track N2 - Train-induced vibrations in soft ground usually have a strong low-frequency component. This component has a characteristic spectrum which is related to the axle sequence and the speed of the train. Its attenuation with distance is weaker than the attenuation for higher frequencies, and it always dominates the far-field ground vibration. Narrow-band frequency analyses clearly show that this ground vibration component is due to the static axle loads. Axle box vibrations have a different characteristic where the first out-of-roundness of the wheels is the only remarkable low-frequency component. Therefore, the dynamic axle loads from wheel and track irregularities are not the reason for the strong ground vibration component. The moving static axle loads generate the quasi-static response of the soil at very low frequencies and at very near distances. A part of the original impulse spectrum is scattered when it propagates through an inhomogeneous ballast and soil with a randomly varying stiffness. The axle impulses are smoother for a higher bending stiffness or a lower support stiffness (under sleeper pads, under ballast mats) of the track. This mitigation of the ground vibration will be demonstrated by measurements at three sites in Switzerland as well as the characteristic of the soil and axle-box vibrations. T2 - Railways Conference CY - Prague, Czech Republic DA - 02.09.2024 KW - Soil and vehicle measurements KW - Train passages KW - Ground vibration KW - Excitation mechanisms KW - Mitigation KW - Under sleeper pads KW - Under ballast mat PY - 2024 AN - OPUS4-61226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Conreaux, Laurence A1 - Said, Samir A1 - Müller, Roger T1 - The excitation, propagation, and mitigation of train-induced ground vibrations from the axle impulses on the track N2 - Train-induced vibrations in soft ground usually have a strong low-frequency component. This component has a characteristic spectrum which is related to the axle sequence and the speed of the train. Its attenuation with distance is weaker than the attenuation for higher frequencies, and it always dominates the far-field ground vibration. Narrow-band frequency analyses clearly show that this ground vibration component is due to the static axle loads. Axle box vibrations have a different characteristic where the first out-of-roundness of the wheels is the only remarkable low-frequency component. Therefore, the dynamic axle loads from wheel and track irregularities are not the reason for the strong ground vibration component. The moving static axle loads generate the quasi-static response of the soil at very low frequencies and at very near distances. A part of the original impulse spectrum is scattered when it propagates through an inhomogeneous ballast and soil with a randomly varying stiffness. The axle impulses are smoother for a higher bending stiffness or a lower support stiffness (under sleeper pads, under ballast mats) of the track. This mitigation of the ground vibration will be demonstrated by measurements at three sites in Switzerland as well as the characteristic of the soil and axle-box vibrations. T2 - Sixth International Conference on Railway Technology: Research, Development and Maintenance CY - Prague, Czech Republic DA - 01.09.2024 KW - Soil and vehicle measurements KW - Train passages KW - Ground vibration KW - Excitation mechanisms KW - Mitigation KW - Under sleeper pads KW - Under ballast mat PY - 2024 DO - https://doi.org/10.4203/ccc.7.13.2 SN - 2753-3239 VL - 7 SP - 1 EP - 13 PB - Civil-Comp Press CY - Edinburgh, United Kingdom AN - OPUS4-61240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Ziemens, Susanne T1 - The response of different buildings to free-field excitation – a study using detailed finite element models N2 - A study on building vibrations has been performed by finite element calculations. Family houses, multi-storey residential buildings, office buildings and office towers have been modelled in detail. The frequency-dependent response due to a free-field excitation has been evaluated for walls, columns and floors. The ratio of building amplitudes to free-field amplitudes starts with uB/u0 = 1 at zero frequency and is usually lower than 1 at 50 Hz, the end of the frequency range considered here. In between, amplifications occur due to several reasons. There are „soil resonances“ where the whole building is vibrating on the compliant soil, “column resonances” where the upper storeys are vibrating on the compliant columns, and the “floor resonances” where the floors are vibrating excited by their supports. Results are presented for all building types, but a special focus is set on office buildings. A parameter study shows the influence of the stiffness of the soil, the number of storeys, and the width of the building. It has been found that the “soil resonance” is strongly modified by the low-frequency floor resonances for the normal office building. The main resonance of a twenty-storey office tower is determined equally by the “soil mode” and the “column mode”. It is an important observation for these office buildings that the resonances can differ for different parts of the building such as the centre, the edge, the corner, and the core of the building. This leads to non-uniform vibration modes across the building, which look like another type of “floor resonance” and which have been observed in several real building projects. Experimental results will be shown which can confirm the calculated phenomena. T2 - EURODYN 2020 XI International Conference on Structural Dynamics CY - Online meeting DA - 13.11.2020 KW - Building vibration KW - Office building KW - Residential building KW - Soil-building resonance KW - Floor resonance KW - Column/wall resonance PY - 2020 SN - 978-618-85072-2-7 SP - 4560 EP - 4576 CY - Athen AN - OPUS4-51678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - The response of different buildings to free-field excitation – a study using detailed finite element models N2 - A study on building vibrations has been performed by finite element calculations. Family houses, multi-storey residential buildings, office buildings and office towers have been modelled in detail. The frequency-dependent response due to a free-field excitation has been evaluated for walls, columns and floors. The ratio of building amplitudes to free-field amplitudes starts with uB/u0 = 1 at zero frequency and is usually lower than 1 at 50 Hz, the end of the frequency range considered here. In between, amplifications occur due to several reasons. There are „soil resonances“ where the whole building is vibrating on the compliant soil, “column resonances” where the upper storeys are vibrating on the compliant columns, and the “floor resonances” where the floors are vibrating excited by their supports. Results are presented for all building types, but a special focus is set on office buildings. A parameter study shows the influence of the stiffness of the soil, the number of storeys, and the width of the building. It has been found that the “soil resonance” is strongly modified by the low-frequency floor resonances for the normal office building. The main resonance of a twenty-storey office tower is determined equally by the “soil mode” and the “column mode”. It is an important observation for these office buildings that the resonances can differ for different parts of the building such as the centre, the edge, the corner, and the core of the building. This leads to non-uniform vibration modes across the building, which look like another type of “floor resonance” and which have been observed in several real building projects. Experimental results will be shown which can confirm the calculated phenomena. T2 - EURODYN 2020 XI International Conference on Structural Dynamics CY - Online meeting DA - 23.11.2020 KW - Building vibration PY - 2020 AN - OPUS4-51679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Train-induced ground vibrations - the emission and transmission from tunnel and surface lines N2 - Train-induced ground vibrations are quite different for tunnel and surface lines. The excitation of the track and ground vibration by the vehicle-track-soil interaction maybe influenced by the stiffer track support of the tunnel invert. The excited waves are propagating on a different path compared to the surface line. The wave propagation in the interior of the soil is calculated by a wavenumber integral in a similar way as the propagation along the surface and a general reduction of < 0.5 has been found. An additional reduction has been found because of the missing Rayleigh wave. The different excitation of tunnel lines is analysed theoretically by the combined finite-element boundary-element method and some results about the influencing tunnel and soil parameters will be shown. Measurements have been made at the Mühlberg-Tunnel in Germany. The vibrations of the train, the track and the soil have been measured simultaneously at the tunnel and a nearby surface line. Spectra will be shown for different train speeds between 60 and 160 km/h. A clear reduction effect for the tunnel line compared to the surface line has been observed in a specific (train-speed-dependent) frequency range. This agrees well with the observations of other research institutes. The mid-frequency tunnel-surface reduction seems to be a consequence of the stiffer track structure which leads to a wider distribution of the axle loads. Therefore, the axle impulses due to the train passage are longer and have a lower frequency content. This will have an effect on the ground vibrations at some distance which are present in case of an irregular transmission path through a ballast and soil with varying stiffness. A similar reduction effect can also be found for other track forms where the axle impulses are distributed on a longer track segment, for example slab tracks, tracks with under ballast plates, under ballast mats or under sleeper pads. T2 - 29th International Congress on Sound and Vibration CY - Prague, Czech Republic DA - 09.07.2023 KW - Ground vibration KW - Railway tunnel KW - Layered soil KW - Surface-tunnel reduction KW - Measurements PY - 2023 SP - 1 EP - 8 PB - IIAV CY - Auburn, USA AN - OPUS4-57962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Train-induced ground vibrations – The emission and transmission from tunnel and surface lines N2 - Train-induced ground vibrations are quite different for tunnel and surface lines. The excitation of the track and ground vibration by the vehicle-track-soil interaction maybe influenced by the stiffer track support of the tunnel invert. The excited waves are propagating on a different path compared to the surface line. The wave propagation in the interior of the soil is calculated by a wavenumber integral in a similar way as the propagation along the surface and a general reduction of < 0.5 has been found. An additional reduction has been found because of the missing Rayleigh wave. The different excitation of tunnel lines is analysed theoretically by the combined finite-element boundary-element method and some results about the influencing tunnel and soil parameters will be shown. Measurements have been made at the Mühlberg-Tunnel in Germany. The vibrations of the train, the track and the soil have been measured simultaneously at the tunnel and a nearby surface line. Spectra will be shown for different train speeds between 60 and 160 km/h. A clear reduction effect for the tunnel line compared to the surface line has been observed in a specific (train-speed-dependent) frequency range. This agrees well with the observations of other research institutes. The mid-frequency tunnel-surface reduction seems to be a consequence of the stiffer track structure which leads to a wider distribution of the axle loads. Therefore, the axle impulses due to the train passage are longer and have a lower frequency content. This will have an effect on the ground vibrations at some distance which are present in case of an irregular transmission path through a ballast and soil with varying stiffness. A similar reduction effect can also be found for other track forms where the axle impulses are distributed on a longer track segment, for example slab tracks, tracks with under ballast plates, under ballast mats or under sleeper pads. T2 - 29th International Congress on Sound and Vibration (ICSV29) CY - Prague, Czech Republic DA - 09.07.2023 KW - Ground vibration KW - Railway tunnel KW - Layered soil KW - Surface-tunnel reduction KW - Measurements PY - 2023 AN - OPUS4-57956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Vehicle Dynamics and Train‑Induced Ground Vibration—Theoretical Analyses and Simultaneous Vehicle, Track, and Soil Measurements N2 - Ground vibrations near railway lines are generated by the forces that are acting between wheel and rail. It seems to be a straight forward assumption that the vehicle dynamics are important for the level and the frequencies of the excitation forces. Different vehicle dynamics phenomena are analysed for their role in the excitation of ground vibrations: rigid body modes of the bogies, elastic (bending) modes of the car body, and elastic modes of the wheelset. The theoretical analyses use rigid body models, simplified elastic models, and detailed elastic models. Some of these problems are vehicle–track interaction problems where 3D finite‑element boundary‑element models have been used for the track and soil. It is shown that the rigid or flexible vehicle modes are well in the frequency range of ground vibrations (4 to 100 Hz). They have an influence on the excitation force but the additional forces are rather small and can be neglected in ground vibration prediction. The theoretical results are checked by experimental results of a simultaneous measurement of vehicle, track, and ground vibrations. KW - Rigid vehicle model KW - Flexible car body KW - Flexible wheelset KW - Dynamic loads KW - Ground vibration PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569796 DO - https://doi.org/10.3390/vehicles5010013 VL - 5 IS - 1 SP - 223 EP - 247 PB - MDPI CY - Basel AN - OPUS4-56979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Vehicle-Track-Soil Interaction of Isolated, Un-isolated and Damaged Railway Tracks N2 - This article deals with two topics of vehicle-track-soil interaction, the mitigation of railway induced ground vibration by soft track elements, and the identification of track damage. Theoretical results have been achieved by a combined finite-element boundary-element method (FEBEM). The theoretical results are confronted with measurements at four sites. Improved mitigation effects have been found for soft rail pads under heavy sleepers. The insertion loss, however, can be too optimistic if a strong vehicle track resonance occurs for the un-isolated reference track. Two measurement sites show this strong vehicle-track resonance at about 80 Hz, which has been approximated by using the results of a wide parameter study including the rail pad, ballast, and soil stiffness, as well as the ballast model and the soil layering. – The detection of slab track damage is mainly based on the differences of the receptance or compliance functions. Theoretical results have been confirmed by measurements at one site where a loss of contact between track plate and base layer was visible. Measurements at a second site with a hidden damage have been compared with the theoretical results of a loose sleeper. The differences between intact (or repaired) and damaged tracks are strong enough to encourage the further development of this method for the identification of track damages. KW - Railway track KW - Track-soil interaction KW - Ground vibration KW - Mitigation KW - Under-sleeper pads KW - Track damage monitoring PY - 2020 DO - https://doi.org/10.4203/ijrt.6.3.2 SN - 2049-5358 VL - 2 IS - 20 SP - 21 EP - 49 PB - Saxe-Coburg Publications CY - London AN - OPUS4-51257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Vibraciones de estructuras multi vanos como forjados, puentes ferroviarios y de carreteras N2 - Se han analizado las frecuencias y las formas modales de las estructuras multi-vanos en teoría y mediante ocho ejemplos medidos. Como consecuencia por los puentes de ferrocarril, se han calculado las amplitudes de resonancia en el dominio de las frecuencias con los espectros del tren, de la fuerza modal, y de la resonancia. Para los vanos (idénticos) continuos resp. simplemente apoyados el acoplamiento es fuerte resp. debil, las frecuencias son separadas resp. agrupadas, las formas modales son globales y globales, la resonancia es menor resp. menor – (igual). Los resultados en el dominio del tiempo se obtiene con la transformación inversa de Fourier o – más robusto – el valor de eficaz por la superposición. T2 - DinEst 2024 Third Conference on Structural Dynamics CY - Seville, Spain DA - 12.09.2024 KW - Multi-span bridges KW - Train passage KW - Resonance PY - 2024 AN - OPUS4-61225 LA - spa AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, R. A1 - Brechbühl, Y. A1 - Lutzenberger, S. A1 - Said, Samir A1 - Auersch, Lutz A1 - Guigou-Carter, C. A1 - Villot, M. A1 - Müller, R. ED - Degrande, G. ED - al., et T1 - Vibration Excitation at Turnouts, Mechanism, Measurements and Mitigation Measures N2 - There is a strong need for cost-effective mitigation measures for turnouts. SBB has initiated a series of examinations using different methodologies to gain a deeper understanding of the excitation mechanisms at low frequencies, in addition to that obtained in the RIVAS project. To date it is not yet clear what constitutes a complete measurement data set that would enable understanding most of the vibration excitation mechanisms in turnouts. Increasing vibration at turnouts in comparison to normal track is observed for all measured frequencies. The different methodologies are presented in the paper. Under-sleeper pads (USP) are a cost-effective method to reduce vibration at frequencies above 63 Hz (1/3 octave), but there is probably no improvement for frequencies below 63 Hz. A first test of new frog geometry did not show relevant improvements in Vibration emission in comparison to a reference frog geometry. Axle box acceleration measurements are an interesting method to identify defects in a turnout. A specialized measurement system of rail roughness could identify certain geometry Problem areas for some frogs. Noise increases also are observed at turnouts for frequencies ranging between 80 to 1000 Hz. The use of railway source models to calculate contact forces for ballasted track and turnouts seems promising, in particular for understanding the influence of ground. KW - Turnout KW - Switch KW - Vibration excitation KW - Vibration measurements PY - 2021 SN - 978-3-030-70288-5 DO - https://doi.org/10.1007/978-3-030-70289-2_42 SN - 1612-2909 VL - 150 SP - 403 EP - 410 PB - Springer Nature Switzerland AG CY - Cham AN - OPUS4-52612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -