TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Prediction of explosion-induced ground and building vibrations - measured wave velocities, transfer functions and attenuation N2 - Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q  0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites. T2 - International Congress on Sound and Vibration (ICSV25) CY - Hiroshima, Japan DA - 08.07.2018 KW - Prediction of explosion induced ground and building vibration KW - Explosion-induced ground vibrations KW - Hammer impact KW - Soil properties KW - Amplitude-distance laws KW - Amplitude-charge weight laws PY - 2018 SN - 978-83-7880-552-6 SN - 2329-3675 SP - 1 EP - 8 PB - Silesian University of Technology Press CY - Gliwice, Poland AN - OPUS4-45506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Said, Samir A1 - Auersch, Lutz T1 - Measurement of slab track behaviour at different sites N2 - Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. T2 - 26th International Congress on Sound and Vibration (ICSV26) CY - Montreal, Canada DA - 07.07.2019 KW - Displacements KW - Train passage KW - Slab track KW - Hammer impact KW - Vibration measurements PY - 2019 AN - OPUS4-48495 LA - eng 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 U6 - 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 - 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 - JOUR A1 - Auersch, Lutz A1 - Song, Jiaojiao T1 - Dynamic damage detection of slab tracks – finite element models on Winkler soil and finite-element boundary-element models on continuous soil N2 - The train passages over intact or damaged slab tracks on different soils have been calculated by two methods. The finite element method (FEM) uses a Winkler soil under the track model by adding a thin “soil layer”. The combined finite element boundary element method has a continuous soil model which is included by the boundary element method. The basic results are the distributions of the track (rail, track plate, and base layer) displacements along the track for a single axle laod. These solutions are superposed to a complete train load and transformed to time histories. The influence of track and soil parameters has been analysed. The main interest is the influence of the track damage. A gap between track plate and base layer of different lengths has been studied for changes in amplitudes and widths of deflection. A best fit to measured track displacements has been found so that the track damage can be identified and quantified. The FEM model with Winkler soil cannot be fitted to the amplitude and width with the same soil parameters. Therefore, the FEBEM model is preferable for these railway track problems. KW - Track damage quantification KW - Finite element method KW - Combined finite-element boundary-element method PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-562207 SN - 2673-4109 VL - 3 IS - 4 SP - 979 EP - 997 PB - MDPI CY - Basel AN - OPUS4-56220 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, R. T1 - Measurement and evaluation tools for ground and building vibrations from industrial pro-cesses, construction work, traffic and other sources N2 - Vibration measurements have many causes and many technical and natural sources. Problems can sometimes be solved by short-term measurements, but in many cases, a long-term measurement is necessary. In long-term measurements of days, weeks, months and even years, it is easy to collect a huge quantity of raw data, but at the end, the post-processing of these data can be exhausting (for example one-year vibration data of a wind energy tower). A software has been developed which con-sists of measuring and evaluation routines where the measuring routines can operate different meas-uring systems and different measuring cards. The main advantage of this software is the fact that the interesting evaluations can be integrated in the measuring process so that the characteristics of the vibration can be extracted without storing all the raw data. Only important time segments are stored, for example train passages. The overall concept of the software and the main evaluation routines will be described in some details. Examples of our measurement experience will illustrate the capabilities of the software. 1) Surveying construction work in nearby sensitive buildings (for example an old wind tunnel), including a stable alarm system and meaningful vibration limits. 2) Prediction of train-induced vibration for a planned building to prevent annoyance and to improve the building design. 3) Modal analysis and long term measurements of several single- or multi-span, concrete or steel bridges 4) Modal and wave analysis of coupled floors in a historical building (“Neues Palais” at Potsdam). 5) Soil properties of various measurement sites (different routines to evaluate the dispersion). Moreover, from many projects, amplitudes, frequencies, and attenuation laws have been collected and analysed for the different sources such as vibratory or impact pile driving and ground compaction, demolition work with different machines, blasting in quarries and in tunnel works, bomb and mine clearing. T2 - 28th International Congress on Sound and Vibration CY - Online meeting DA - 24.07.2022 KW - Ground vibration KW - Building vibration KW - Measurement KW - Evaluation KW - Modes KW - Waves PY - 2022 SP - 1 EP - 8 AN - OPUS4-56602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, R. T1 - Natural frequencies and modes of poles, beams, floors, road and rail bridges N2 - In the last three decades, the vibrations of many floors and bridges have been measured. The contribution shows some evaluation methods, experimental results and some modelling and theoretical results. Simple evaluation methods have been developed for single and coupled floors. Two coupled beams have been measured in good agreement with the theory. A more complex coupling model has been found for a large wooden floor in a castle consisting of six floor bays which correlates well with the measurements. Damaged and intact poles have been tested by their natural frequencies and damping values, and a fair correlation between the degree of damage and the shift of the frequency. Road bridges have been analysed in detail and some examples are presented. Railway bridges and trains are studied for resonant excitation. The risk of resonance can be estimated in frequency domain by using axle-sequence spectra of the train and the natural frequencies of the bridge. A measurement example shows the amplification, but even stronger the cancellation of the subsequent axle responses. Several high-speed trains and freight trains have been analysed for their potential resonance amplification. T2 - International Conference on Noise and Vibration Engineering (ISMA/USD 2020) CY - Online meeting DA - 07.09.2020 KW - Modalanalyse KW - Bauwerke KW - Bauteile KW - Brücken KW - Achsfolgespektren PY - 2020 SP - 1573 EP - 1585 PB - KULeuven CY - Leuven AN - OPUS4-51211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Auersch, Lutz A1 - Said, Samir ED - Bian, Xuecheng ED - Chen, Y. ED - Ye, X. T1 - Vibration measurements for the control of damaged and repaired railway tracks N2 - This contribution presents experimental methods to detect track damage. At BAM (Federal Institute of Material Research and Testing), a measuring car with a measuring system of 72 channels, geophones, mountings, cables, harmonic and impulsive exciters is used for dynamic measurements of the track, the soil and buildings. An instrumented hammer allows force measurements and to evaluate transfer functions of the track, and the soil. Wave measurements are used to identify the soil characteristics. Train passages are measured at the track and for the train induced ground vibrations. In addition to these in situ options, tests of tracks or track elements can be performed in a large laboratory. KW - Track vibration KW - Track damage PY - 2018 SN - 978-981-10-4507-3 U6 - https://doi.org/10.1007/978-981-10-4508-0_2 SP - 13 EP - 30 PB - Springer CY - Singaporer AN - OPUS4-45457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - Strukturschwingungen und Schwingungsminderung - Bauwerksmodelle, Messungen vor Ort und auf dem Versuchsgelände der BAM T1 - Structural Vibrations and Vibration Reduction Building Models, On-site Measurements and Test Site of the BAM N2 - Die Grundidee einer Schwingungsminderung ist es eine tiefe Eigenfrequenz der Struktur zu erreichen, so dass höhere Frequenzen abgemindert werden. Das gilt für die Minderung an der Quelle, zum Beispiel einem Eisenbahngleis, und für die Minderung am Empfänger, dem Gebäude. Die Eigenfrequenz ermittelt man aus dem Verhältnis der Auflagersteifigkeit und der Masse. Wie ist die Masse bei einem Gebäude zu wählen? Und wie ist die Untergrundsteifigkeit zu berücksichtigen? Als Referenzsituation ohne Minderungsmaßnahme? Der Beitrag bringt Rechenergebnisse zu abgefederten Gebäuden mit einfachen und komplexen (FE-) Modellen, Mess- und Rechenergebnisse zur Schwingungsübertragung von unabgefederten Gebäuden. Es wird der Einfluss der Abstimmfrequenz, der Bodensteifigkeit und der „starren“ Gebäudemasse untersucht. Die komplexen Gebäudemodelle erlauben, neben der Berechnung einer elastischen Gebäudelagerung, auch die Variation von Gebäudeparametern zur Reduktion der Deckenschwingungen. Den Ergebnissen bei der Erschütterungs-übertragung in Gebäude werden zwei ähnliche Beispiele zur elastischen Maschinenlagerung und zur elastischen Gleislagerung gegenübergestellt. T2 - 6. VDI Fachtagung Baudynamik CY - Würzburg, Germany DA - 17.04.2018 KW - Rechenmodelle KW - Elastische Gebäudelagerung PY - 2018 SN - 978-3-18-092321-5 SN - 0083-5560 VL - 2321 SP - 421 EP - 434 PB - VDI-Verlag CY - Düsseldorf AN - OPUS4-45471 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir T1 - Slab track behaviour under train passage and hammer impact – Measurements at different sites and calculated track interaction with continuous soils N2 - This contribution intends to give an overview on the vibration behaviour of slab tracks in comparison of measurements and calculations and also by comparison of different track types at more than ten different measuring sites. In theory, tracks on continuous soil are calculated by the frequency-wavenumber domain method. In experiment, geophone measurements are transformed to displacement results. Two aspects of track behaviour are considered, the frequency-dependant compliance of the track, measured by hammer impact, and the deflection under a passing axle load. In theory, the response to a single axle can be calculated, whereas in experiment, only the passage of the whole train can be measured. For comparison of theory and experiment, the calculated deflection under a single axle is superposed to get the response of the whole train. As a result, the slab track characteristics are completely different from the ballast track characteristics where each axle can be seen in the time histories. The slab track has a more global behaviour where only a whole bogie can be found in the track response and moreover, the two neighbouring bogies are not completely separated. The measurement of the different track elements (rail, sleeper, track plate, base layer) and the frequency-dependant compliances with possible resonances yield further information About the properties of the track elements. The calculations show that the soil has the dominant influence on the amplitudes and the width of the track-plate displacements. In the measurement results, the following parameters are analysed: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, voided sleepers, an elastic layer, the mortar layer, and different soils at different places. Finally, a good agreement between measured and calculated results is found for the normal and some special (damaged, floating) slab tracks. KW - Slab track KW - Train passage KW - Hammer impact KW - Compliance function KW - Track deflection PY - 2020 UR - https://iiav.org/ijav/index.php?va=viewpage&vaid=177&id_number=95 U6 - https://doi.org/10.20855/ijav.2020.25.31622 SN - 1027-5851 VL - 25 IS - 3 SP - 341 EP - 354 PB - International Institute of Acoustics and Vibration CY - Gliwice AN - OPUS4-51346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -