TY - CONF A1 - Auersch, Lutz T1 - Prediction of building noise and vibration – 3D finite element and 1D wave propagation models N2 - Construction work or traffic excite nearby buildings, and the perceptible or audible vibration can be a nuisance for the inhabitants. The transfer of the vibration from the free field to the building has been calculated by the finite element method for many models in consultancy and research work. The analysis for all storeys of certain building points such as walls, columns and floors unveiled some rules, some typical modes, and some wavetype responses. A simplified building-soil model has been created, which includes well these effects of building-soil resonance, wall/column resonance, floor resonances, and the high-frequency reduction. The model consists of one wall for a wall-type apartment building or a column for each specific part (mid, side or corner) of a column-type office building. The building response in the high-frequency (acoustic) region is calculated as mean values over all storeys and over wider frequency bands, by wave-type asymptotes of an infinitely tall building, and by the soil to wall ratio of impedances. The secondary noise is predicted by Transfer values between the building vibration (center of floors, walls at a room corner) and the sound pressure. T2 - Euronoise 2021 CY - Online meeting DA - 25.10.2021 KW - Building vibration KW - Finite element models KW - Soil-wall-floor model KW - Apartment building KW - Office tower PY - 2021 SN - 978-989-53387-0-2 SP - 1792 EP - 1801 AN - OPUS4-53702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Prediction of ground vibrations from rail tunnels –finite-element, boundary-element and wavenumber calculations N2 - The prediction of ground and building vibrations has been established for surface lines and has now been extended to tunnel lines. The wave propagation in homogeneous or layered soils (the transmission) is calculated by an integration in wavenumber domain. The wave amplitudes at different distances and for different frequencies will be analysed for the following situations. 1. The horizontal propagation from a surface point to a surface point constitutes the basic rules. 2. The horizontal propagation from a source point at depth to a receiver point at depth which is related to a building with a deep basement or on a pile foundation. 3. The propagation from depth to the surface, which is the normal case for free-field measurements, has some different characteristics, for example a weaker attenuation with the horizontal distance from the source, which can be approximated by the full-space solution and the reflection rules for incident waves. The emission from a tunnel structure has been calculated by a finite-element model of the tunnel combined with a boundary-element model of the soil giving the reduction compared to a point-load excitation. The immission has been analysed by finite-element models of tunnel-soil-building systems for examples of research and consultancy work. Measurement results from a high-speed and a metro line confirm some of the established rules. Figure T2 - Int. Conf. RASD, Recent Advance in Structural Dynamics CY - Southampton, GB DA - 01.07.2024 KW - Ground vibration KW - Tunnel line KW - Wave propagation KW - Wavenumber method KW - Building vibration KW - Thin layer method PY - 2024 SP - 1 EP - 12 CY - Southampton AN - OPUS4-61266 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Railway vibration – fast physics-based models for the prediction of ground vibration and the identification of track damage N2 - The following applications of machine learning will be discussed: 1. The prediction of the wave propagation from a railway line (completely physics based for surface lines, physics-based machine learning for tunnel lines) 2. The track behaviour for the emission of train-induced ground vibration (physics based for homogeneous soil, machine learning for layered soil) 3. Track damage detection and quantification from frequency response functions and moving load responses 4. Bridge damage detection and localisation from modal analysis and moving load 5. The use of axle-box acceleration for the identification of track/sub-soil condition and bridge resonances. The prediction of railway vibration usually needs time-consuming finite element, boundary element and wavenumber domain calculations. For a user-friendly prediction software however, fast calculations are needed. Several time-consuming detailed calculations have been used to develop simpler and fast models for the surface railway lines. The more challenging prediction from tunnel lines will be attacked by purely mathematical and by physics-informed machine learning. The dynamic stiffnesses of isolated or un-isolated railway tracks from detailed calculations with a continuous soil have been approximated with the simpler Winkler soil. The vehicle-track resonance (P2 resonance) rules the effect of the mitigation measures, and it can also be used for the on-board monitoring of the track and sub-soil condition. For the identification of track damage such as gaps between sleepers, track slabs and layers, detailed models with a continuous soil have been updated to get the best fit to the measured frequency response functions from hammer tests and the deformation pattern from the moving load response. Whereas the track damage can be locally identified, this is more difficult for bridges where the modal analysis gives mainly global information. The influence lines of the inclination for statically passing vehicles (locomotive, truck, compaction roller) have been used to localise bridge damage (stiffness variations). The on-board monitoring of rail bridges needs special conditions (regular trains with special speeds) to excite and measure the bridge resonance. T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024) CY - Potsdam, Germany DA - 10.06.2024 KW - Vibration prediction KW - Track damage detection KW - Human and machine learning KW - Wave propagation KW - Surface line KW - Tunnel KW - Bridge resonance PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612462 DO - https://doi.org/10.58286/29865 SN - 1435-4934 SP - 1 EP - 9 PB - NDT.net CY - Kirchwald AN - OPUS4-61246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Railway-induced ground and building vibrations – Analysis in frequency-wavenumber domain and fast prediction with approximate models N2 - A simple and fast prediction scheme is presented for train-induced ground and building vibrations. For the emission, finite-element boundary-element or multiple-beam-on-continuous-soil models of the track have been analysed and approximated by faster track-on-Winkler-soil models. The vehicle-track interaction due to irregularities yields the excitation forces. For the transmission of waves in the soil, the wavenumber integral of the compliance of layered soils has been evaluated. The calculation time is reduced for the prediction by using the solution of a homogeneous half-space with a frequency-dependent wave velocity (the dispersion) of the soil. For the immision, many 2 and 3-dimenisonal finite-element building models have been investigated, and a good approximation has been established by a 1-dimensional soil-wall-floor model. In addition, the axle sequence of the train, the quasi-static and the “scattered” response of the soil, and the wave propagation from a tunnel to a pile foundation of a building have been included. T2 - ISMA-Conference 2022 CY - Leuven, Belgium DA - 12.09.2022 KW - Ground vibration KW - Simple prediction KW - Vehicle-track interaction KW - Layered soil KW - Soil-building interaction KW - Soil-wall-floor model KW - Propagation from a tunnel KW - Tunnel-pile transfer PY - 2022 SP - 1 EP - 13 PB - KU Leuven CY - Leuven AN - OPUS4-56603 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Reduction of ground-induced building vibrations by kinematic and inertial soil-structure interac-tion and by base isolation N2 - Many buildings on the soil have been measured and the transfer function freefield-to-building is ana-lysed. In general, an amplification at low frequencies, an amplification for the floor resonances, and a reduction for higher frequencies can be observed. Most of the measurement examples show a flexible behaviour along the height of the buildings. The prediction of building vibration consists typically of three steps. At first, the dynamic stiffness of the foundation and secondly the kinematic soil-structure interaction has to be calculated for example by the combined finite-element boundary-element meth-od. The stiffness of the foundation reduces the incoming waves (the kinematic interaction). Finally, the inertial interaction of the building with the foundation soil is calculated by the conventional finite ele-ment method where the dynamic foundation stiffness from the first step is added at the bottom of the building. The building on the compliant soil has a fundamental vertical resonance usually below 10 Hz. A parametrical variation clearly shows the influence of the elasticity of the building on this reso-nance frequency and amplitude. Moreover for column-type office buildings, the low-frequency floor resonances can further reduce this fundamental frequency. A 1-dimensional model has been estab-lished which can well approximate the behaviour of the 3-dimensional building models. It is used to demonstrate the effect of a base isolation with soft elements at the foundation. A rigid building model clearly over-estimates the isolation effect, which is smaller for a model with flexible walls, columns and floors. An even simpler model of an infinitely high building is suggested for the mitigation effect, and the resonance frequency of the rigid building should be replaced by a better performance indica-tor, which is based on the impedance ratio of the isolation and the wall and which can be also ex-pressed as a characteristic frequency. T2 - 30th International Congress on Sound and Vibration CY - Amsterdam, Netherlands DA - 08.07.2024 KW - Building vibrations KW - Base isolation KW - Foundation stiffness KW - Kinematic soil-structure interaction KW - Transfer functions of flexible buildings PY - 2024 SN - 978-90-90-39058-1 SN - 2329-3675 SP - 1 EP - 8 AN - OPUS4-61245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Soil-foundation-structure problems related to train induced vibrations - the kinematic interaction of tunnel excited pile foundations and the inertial interaction of high rise buildings N2 - The soil-foundation-structure interaction is always important when building vibrations due to train passages have to be considered. The frequency range for train vibrations is up to 100 Hz. Normally, soft surface soils are crucial so that the wavelength can be much smaller than the foundation dimensions. Three topics are of interest for the prediction and the under-standing of building vibrations. 1. The „kinematic interaction“ or the „added foundation ef-fect“, which is calculated either by the combined boundary-element finite-element method or by the wavenumber domain method, results in a reduction of the free-field vibration. The stiff-ness of the foundation resists the wave deformation, plates and walls for horizontally propa-gating waves or piles for vertically incident waves. 2. The „inertial interaction“ or the „added building effect“ yields an amplification around the vertical building resonance, which may be a rigid mode on the compliant soil or a flexible mode for high-rise buildings, and a reduction at higher frequencies. This has been analysed by detailed finite element models of apartment and office buildings. 3. Base isolation is a method to further reduce building vibrations. It is important to know the soil-foundation impedance for the possible reduction, as well as the correct building impedance. A high-rise building cannot be considered as a rigid mass model. It has a frequency-dependent behaviour with longitudinal waves travelling from the founda-tion to the top of the building which include the effect of floor vibrations. Experiences from building projects in Vienna, Frankfort and Berlin will give some additional results for the ex-citation from tunnel lines, the kinematic response of pile foundations, and the inertial re-sponse of the flexible multi-storey buildings. T2 - COMPDYN 2023 CY - Athen, Greece DA - 12.06.2023 KW - Kinematic Interaction KW - Inertial Interaction KW - Surface Foundation KW - Pile Foundation KW - High-Rise Building PY - 2023 SP - 1 EP - 14 PB - NTUA CY - Athens AN - OPUS4-57959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Some resonance effects of non-typical trains and railway bridges investigated by a frequency-domain method N2 - The resonances of railway bridges have often been analysed for short bridges under periodical high-speed trains, for simply supported one-span bridges, for the fundamental bridge mode, and by time-domain analyses. Many time-consuming calculations have been performed to establish simplified rules for standards. In this contribution, the passage of different (existing, new and hypothetic) trains over different bridges will be analysed in frequency domain by using three separated spectra with the purpose to get a better physical insight in the phenomena. At first, the excitation spectrum of the modal forces is built by the mode shape and the passage time of the train over the bridge. The second spectrum is the frequency response function of the bridge which include the modal frequency, damping and mass. The third part is the spectrum of the axle sequence of an arbitrary train which is not limited to periodical or specific (conventional, articulated, regular or standard) trains and which does not include any bridge parameters. The final solution in frequency domain is obtained as the product of these three complex, strongly varying spectra for the dominating bridge mode or in general as the sum of these products over all relevant bridge modes. The time domain solution is obtained via the inverse Fourier transform, and the resulting time histories have been successfully compared with some measurement results. The method is applied to the vertical and torsional modes of a mid-long 1-span bridge on elastomeric bearings under standard train speeds, and to a long multi-span integral bridge under long periodical freight trains. Different resonance and cancellation effects have been found for systematically varied train speeds according to the axle sequence of the whole train which is dominated by the two locomotives in that case. To be more specific, the first torsional mode of the mid-span bridge is excited for a train speed of 100 km/h whereas the second bending mode is excited for a train speed of 160 km/h. In both cases, the other mode is suppressed by the minima of the axle-distance spectra. In addition, the case of the German high-speed train ICE4 and the very high-speed hyperloop case will be discussed briefly. In general, it is shown that resonance effects are also worth to be studied for freight and passenger trains with lower speeds. T2 - XII International Conference on Structural Dynamics CY - Delft, The Netherlands DA - 03.07.2023 KW - Railway bridge KW - Transfer function KW - Modal force spectrum KW - Axle-sequence spectrum KW - Freight train KW - Passenger train KW - High-speed train KW - 2-span bridge KW - Long-span bridge PY - 2023 SP - 1 EP - 10 PB - TU Delft CY - Delft AN - OPUS4-57961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir T1 - System and damage identification for cars, floors and roofs, bridges, tracks and foundations by modal analyses, frequency response functions and moving-load responses N2 - The following objects have been analysed by frequency response functions and moving load responses. A simple modal analysis which is based on the transformed and weighted system equations has been tested for an automotive test car and for many floors in many buildings to get some rules for their natural frequency and damping. Moreover, six neighboured equal, weakly coupled, wooden floors in a castle have been measured by ambient and hammer excitation, and a special method to extract the different mode shapes of the closely spaced natural frequencies has been developed and tested. Different foundations, for which the soil-structure interaction is generally important, have been measured and compared with finite-element boundary-element models of varying soil properties. Similarly by FEBEM calculations, damages in railway tracks have been identified from flexibility functions (frequency response functions) and from the moving-load responses to normal train operation. Rail and foot bridges have been measured during train passages and by quasi-static tests with moving vehicles. The repeatability of the inclinometer measurements has been checked for different passages, passage directions, and measurement campaigns at a six-span foot bridge. Two rail bridges at the Hanover-Würzburg high-speed line have been measured and evaluated for integrity and for the train- and speed-dependent bridge resonances. The relation between the multi-axle and the single-axle excitation can be solved in frequency domain by the axle-sequence spectrum of the vehicle or the whole train. The single axle response has been used to identify track and bridge damages in laboratory and in situ. T2 - 10th International Operational Modal Analysis Conference (IOMAC 2024) CY - Naples, Italy DA - 21.05.2024 KW - Weakly coupled floors KW - Bridge passage KW - Track damage KW - Foundation-soil interaction KW - Flexibility function KW - Moving load response PY - 2024 SN - 978-3-031-61420-0 DO - https://doi.org/10.1007/978-3-031-61421-7_19 SN - 2366-2557 SP - 187 EP - 195 PB - Springer Nature Switzerland AG CY - Cham, Schweiz AN - OPUS4-61248 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 -