Filtern
Erscheinungsjahr
- 2023 (17)
- 2022 (16)
- 2021 (14)
- 2020 (12)
- 2019 (17)
- 2018 (6)
- 2017 (15)
- 2016 (11)
- 2015 (17)
- 2014 (7)
- 2013 (7)
- 2012 (15)
- 2011 (10)
- 2010 (8)
- 2009 (9)
- 2008 (9)
- 2007 (8)
- 2006 (18)
- 2005 (14)
- 2004 (12)
- 2003 (6)
- 2002 (7)
- 2001 (7)
- 2000 (5)
- 1998 (2)
- 1997 (6)
- 1996 (1)
- 1995 (2)
- 1994 (6)
- 1991 (2)
- 1990 (2)
- 1989 (4)
- 1988 (4)
- 1987 (5)
- 1986 (9)
- 1985 (2)
- 1984 (6)
- 1983 (4)
- 1982 (1)
- 1981 (2)
- 1980 (1)
Dokumenttyp
- Vortrag (134)
- Zeitschriftenartikel (66)
- Beitrag zu einem Tagungsband (66)
- Beitrag zu einem Sammelband (32)
- Forschungsbericht (14)
- Posterpräsentation (13)
- Buchkapitel (1)
Sprache
- Englisch (170)
- Deutsch (149)
- Spanisch (5)
- Französisch (2)
Schlagworte
- Ground vibration (39)
- Layered soil (13)
- Slab track (11)
- Mitigation (10)
- Railway track (10)
- Bahnerschütterungen (9)
- Erschütterungen (9)
- Finite-element boundary-element method (9)
- Track-soil interaction (9)
- Train passage (9)
- Vehicle-track interaction (9)
- Hammer impact (8)
- Building vibration (7)
- Layered soils (7)
- Schienenverkehr (7)
- Train-induced ground vibration (7)
- Vibration measurements (6)
- Excitation forces (5)
- Field tests (5)
- Track vibration (5)
- Train speed (5)
- Vehicle-track-soil interaction (5)
- Bodenerschütterungen (4)
- Container loading (4)
- Drop test (4)
- Emission (4)
- Erschütterungsminderung (4)
- Erschütterungsprognose (4)
- Finite element method (4)
- Force transfer (4)
- Foundation load (4)
- Railway (4)
- Soil-building interaction (4)
- Track damage (4)
- Tunnel (4)
- Wavenumber integrals (4)
- Wellenausbreitung (4)
- Wellengeschwindigkeit (4)
- Attenuation (3)
- Axle impulses (3)
- Axle sequence (3)
- Ballast track (3)
- Base isolation (3)
- Bauwerk-Boden-Wechselwirkung (3)
- Bodendynamik (3)
- Continuously inhomogeneous soils (3)
- Deckenschwingungen (3)
- Dispersionsmessung (3)
- Elastische Gleiselemente (3)
- Filter effects (3)
- Immissionsprognose (3)
- Irregular soil (3)
- Irregularities (3)
- Measurement (3)
- Measurements (3)
- Pile bending stiffness (3)
- Pile foundation (3)
- Prediction (3)
- Railway bridge (3)
- Randomly heterogeneous soil (3)
- Scattering (3)
- Soil stiffness (3)
- Train passages (3)
- Wind energy tower (3)
- ground vibration (3)
- mitigation (3)
- railway track (3)
- 2-span bridge (2)
- Achsfolgespektren (2)
- Amplitude-distance laws (2)
- Amplituden-Abstands-Gesetz (2)
- Apartment building (2)
- Axle box measurements (2)
- Axle-sequence spectrum (2)
- Ballast tracks (2)
- Bauteile (2)
- Bauwerke (2)
- Bodeneigenschaften (2)
- Bodensteifigkeit (2)
- Bodenübertragungsfunktion (2)
- Boundary element method (2)
- Bridge resonance (2)
- Brücken (2)
- Deckenresonanz (2)
- Displacements (2)
- Dynamic testing (2)
- Elastische Elemente (2)
- Elastische Gebäudelagerung (2)
- Environmental vibrations (2)
- Erschütterungsausbreitung (2)
- Erschütterungsursachen (2)
- Evaluation (2)
- Finite element models (2)
- Floating slab track (2)
- Foundations (2)
- Freight train (2)
- Frequenzbereiche (2)
- Gebäudeschwingungen (2)
- Geschichter Boden (2)
- Gleiströge (2)
- Ground vibration measurements (2)
- Halbraum (2)
- Hammer tests (2)
- High-speed train (2)
- High-speed trains (2)
- Immission (2)
- Irregular ballast (2)
- Körperschall (2)
- Modalanalyse (2)
- Office tower (2)
- Passenger train (2)
- Plate-soil interaction (2)
- Rail roughness (2)
- Railway measurement campaign (2)
- Railway tracks (2)
- Railway tunnel (2)
- Railway vibration (2)
- Railways (2)
- Randelementmethode (2)
- Rayleigh wave (2)
- Rechenmodelle (2)
- Resonance (2)
- Scattered axle impulses (2)
- Schwingung (2)
- Soil properties (2)
- Soil-structure interaction (2)
- Soil-wall-floor model (2)
- Static axle loads (2)
- Surface line (2)
- Surface-tunnel reduction (2)
- Track damage monitoring (2)
- Train excitation (2)
- Transmission (2)
- Under sleeper pad (2)
- Under-ballast plate (2)
- Varying track stiffness (2)
- Vehicle–track interaction (2)
- Vibration measurement (2)
- Vibration reduction (2)
- Vollraum (2)
- Wave excitation (2)
- Wave propagation (2)
- Wavenumber method (2)
- Wellenausbreitung in der Tiefe (2)
- Zuganregung (2)
- Zuggeschwindigkeit (2)
- floor vibration (2)
- modal analysis (2)
- track-soil interaction (2)
- undersleeper (2)
- wave analysis (2)
- Übertragungsfunktion (2)
- Übertragungsmatrizen (2)
- 1-D insertion loss (1)
- Achsimpulse (1)
- Achslasten (1)
- Acoplamiento Método de los Elementos de Contorno-Método de los Elementos Finitos (1)
- Amplitude-charge weight laws (1)
- Amplitude-distance law (1)
- Amplituden-Abstands-Gesetze (1)
- Amplitudenabnahme (1)
- Approximationsverfahren (1)
- Assessment (1)
- Auflagerbedingungen (1)
- Axle loads (1)
- Axle pulses (1)
- Axle-load spectra (1)
- Axle-sequence (1)
- Bahngleis (1)
- Ballast mat (1)
- Ballasted track (1)
- Batiments (1)
- Baudynamik (1)
- Bauwerksschwingungen (1)
- Beam dynamics (1)
- Beam-soil interaction (1)
- Bending waves (1)
- Blasting charge (1)
- Boden (1)
- Boden-Bauwerk-Übertragung (1)
- Bodendämpfung (1)
- Bodenschlitz (1)
- Boundary Element Method-Finite Element Method coupling (1)
- Boundary element (1)
- Boundary elements (1)
- Bridge (1)
- Bridge track (1)
- Bridge vibration (1)
- Brückengleis (1)
- Brückenpfeiler (1)
- Building response (1)
- Cancellation (1)
- Cars (1)
- Column/wall resonance (1)
- Combined finite-element boundary-element method (1)
- Compliance function (1)
- Components of excitation (1)
- Continuous soil (1)
- Damage detection (1)
- Damping (1)
- Decke-Wand-Boden-Modell (1)
- Deckendämpfung (1)
- Deckeneigenfrequenz (1)
- Deckeneigenfrequenzen (1)
- Deckenmessungen (1)
- Deckenübertragung (1)
- Dispersion (1)
- Doppler effect (1)
- Downburst (1)
- Drop height (1)
- Dynamic axle loads (1)
- Dynamic loads (1)
- Dynamic pile and pile group stiffness (1)
- Dynamic soil-structure interaction (1)
- Dynamik (1)
- Dynamische Radlasten (1)
- Dämpfung (1)
- Einfügungsdämmung (1)
- Eisenbahngleis (1)
- Eisenbahnschwingungen (1)
- Elastic length (1)
- Elastic track elements (1)
- Elements elastiques (1)
- Erschütterungen im Fernfeld (1)
- Erschütterungsemission (1)
- Erschütterungsimmission (1)
- Erschütterungsmessungen (1)
- Erschütterungstransmission (1)
- Experimental verification (1)
- Explicit Green´s functions (1)
- Explosion (1)
- Explosion-induced ground vibrations (1)
- FEBEM and simplified methods (1)
- Fahrgeschwindigkeit (1)
- Fahrwegdynamik (1)
- Fahrwegnachgiebigkeit (1)
- Fahrzeug-Fahrweg-Boden-Wechselwirkung (1)
- Fahrzeugdynamik (1)
- Fahrzeugschwingungen (1)
- Fequency domain (1)
- Feste Fahrbahn (1)
- Filter effect of the soil (1)
- Finite element (1)
- Finite-Element-Methode (1)
- Finite-element boudnary-element method (1)
- Finite-element method (1)
- Flexibility (1)
- Flexible car body (1)
- Flexible plate (1)
- Flexible wheelset (1)
- Floor amplification (1)
- Floor resonance (1)
- Floors (1)
- Footbridge (1)
- Foundation reduction (1)
- Frequency response function (1)
- Frequency-specific attenuation (1)
- Frequency-wavenumber method (1)
- Fundamente (1)
- Fundamentschwingungen (1)
- Fundamentübertraung (1)
- Gebäudelagerung (1)
- Gebäudemodelle (1)
- Gebäudeschwingungen, Deckenschwingungen, Wellenausbreitung (1)
- Geometric trackbed irregularities (1)
- Geometric vehicle and track irregularities (1)
- Geometrie (1)
- Gleisschwingungen (1)
- Heavy sleeper (1)
- High-Rise Building (1)
- High-rise buildings (1)
- Hochgeschwindigkeitszüge (1)
- Homogener und geschichteter Halbraum (1)
- Immissionsminderung (1)
- Impedanzmethode (1)
- Inertial Interaction (1)
- Inertial interaction (1)
- Inhomogeneous soils (1)
- Insertion loss (1)
- Interacción dinámica suelo-estructura (1)
- Interaction (1)
- Interior load (1)
- Irrégularités et forces roue-rail (1)
- Kinematic Interaction (1)
- Kinematic and inertial soil-pile-building (1)
- Kinematic interaction (1)
- Kopplung des Fahrzeug-Fahrweg-Untergrund-Systems (1)
- Kraft auf den Boden (1)
- Laboratory tests (1)
- Long-span bridge (1)
- MASW (1)
- Mass drop (1)
- Material damping (1)
- Measured railway vibrations (1)
- Measurement campaigns (1)
- Mehrfeld-Decken (1)
- Messtechnische Ergebnisse (1)
- Minderung (1)
- Mitigation measures (1)
- Modal analysis (1)
- Modal force spectrum (1)
- Modal load spectrum (1)
- Modell (1)
- Modes (1)
- Modes and waves (1)
- Monitoring (1)
- Movin load test (1)
- Moving load (1)
- Moving loads on tracks (1)
- Multi-beam method (1)
- Multi-beam model (1)
- Multi-beam track model (1)
- Multi-beam-on-support model (1)
- Nachgiebigkeiten (1)
- Non-synoptic wind event (1)
- Normung (1)
- Obstacles (1)
- Office building (1)
- Ondes du sol multicouche (1)
- Overhead transmission line (1)
- Parametererregung (1)
- Parametric excitation (1)
- Pfahlnachgiebigkeiten (1)
- Pile Foundation (1)
- Pile foundations (1)
- Pile groups (1)
- Pile-soil interaction (1)
- Prediction of explosion induced ground and building vibration (1)
- Prediction software (1)
- Predictions (1)
- Prognose (1)
- Prognoseprogramm (1)
- Prognoseverfahren (1)
- Propagation from a tunnel (1)
- Quasi-static response; (1)
- Radiation damping (1)
- Rail pad (1)
- Railbridge (1)
- Railway forces (1)
- Railway induced ground vibration (1)
- Railway induced vibration (1)
- Railway track vibration (1)
- Railway trafiic (1)
- Random dynamics and vibrations (1)
- Random stiffness variation (1)
- Rayleighwellendispersion (1)
- Rechenmodell (1)
- Rechenverfahren (1)
- Reduction (1)
- Residential building (1)
- Resonancia en edificaciones (1)
- Resonant response (1)
- Resonanzamplitude (1)
- Richtige Fahrzeugmasse (1)
- Rigid vehicle model (1)
- SASW (1)
- SPAC (1)
- Scattering damping (1)
- Schichtresonanz (1)
- Schienenfahrweg (1)
- Schienenfahrwege (1)
- Schiffstoß (1)
- Schwellenabstandsanregung (1)
- Simple and fast prediction (1)
- Simple prediction (1)
- Simultanmessungen (1)
- Sleeper pad (1)
- Sleeper passage (1)
- Soft track elements (1)
- Soil forces (1)
- Soil transfer function (1)
- Soil-building resonance (1)
- Soil-pile interaction (1)
- Soil-wall floor model (1)
- Spektralanalyse (1)
- Static railway loads (1)
- Stiffness (1)
- Stiffness variation (1)
- Stockwerkrahmen (1)
- Stockwerksschwingungen (1)
- Störgrößen (1)
- Surface Foundation (1)
- Switch (1)
- Target stiffness (1)
- Theoretische Modelle (1)
- Trace (1)
- Track (1)
- Track alignment (1)
- Track and vehicle irregularities (1)
- Track beam (1)
- Track compliance (1)
- Track damage quantification (1)
- Track deflection (1)
- Track deformation (1)
- Track displacements (1)
- Track dynamic (1)
- Track filter (1)
- Track filtering (1)
- Track irregularities (1)
- Track-soil and vehicle-track resonances (1)
- Train configuration (1)
- Train induced ground vibration (1)
- Train-induced vibration (1)
- Tran speed (1)
- Transfer fuction (1)
- Transfer function (1)
- Trench (1)
- Tunnel line (1)
- Tunnel track (1)
- Tunnel vibration (1)
- Tunnel-pile transfer (1)
- Tunnel-to-surface reduction (1)
- Tunnelstrecke (1)
- Turnout (1)
- Under sleeper pads (1)
- Under-sleeper pads (1)
- Varying soil stiffness (1)
- Varying stiffness (1)
- Verifikation (1)
- Verkehrserschütterungen (1)
- Vibration (1)
- Vibration excitation (1)
- Vibration isolation (1)
- Vibrations dues aux trains (1)
- Wave attenuation (1)
- Wave theory of attenuation (1)
- Wave velocity (1)
- Wave-number integrals (1)
- Wavenumber domain (1)
- Waves (1)
- Wellenfeld (1)
- Wellenfeldberechnung (1)
- Wellenzahlmethode (1)
- Wheel out-of-roundness (1)
- Wheel-rail irregularities and forces (1)
- Wheelset (1)
- Wheelset accelerations (1)
- Wide sleeper (1)
- Windenergieanlagen (1)
- Zerstreute Achsimpulse (1)
- elastische Gebäudelagerungen (1)
- layered soil (1)
- sleeper pads (1)
- zerstreute Achslastimpulse (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (82)
- 7.2 Ingenieurbau (82)
Eingeladener Vortrag
- nein (134)
Train passages induce forces on the track, train-induced vibrations propagate through the soil and excite neighbouring buildings. The emission, which is the first part of the prediction of vibrations near railway lines, is presented by focusing on the dynamic axle loads. The calculation of the axle loads is based on the vehicle-track-soil interaction. This interaction calculus utilises the dynamic stiffness of the vehicle (the inertia of the wheelset) and the dynamic stiffness of the track-soil system. Based on various time consuming finite-element boundary-element calculations, an approximate track-soil model has been established. The vehicle-track-soil analysis yields several transfer functions between the various geometric or stiffness irregularities and the axle loads of the train. Geometric irregularities of the vehicle (the wheels) and the track (rail surface and track alignment) are the simplest components. Geometric irregularities of the subsoil (trackbed irregularities) have to be transferred to effective irregularities at rail level. The bending stiffness of the track is filtering out the short-wavelength contribution. Stiffness irregularities occur due to random variations in the ballast or the subsoil, which must also be transferred to effective track irregularities, and due to the discrete rail support on sleepers. All necessary transfer functions for the prediction of axle-load spectra are presented as general formula and as specific graphs for differing vehicle and track parameters. The prediction method is applied to a ballast track and a slab track and compared with corresponding axle-box measurements. Moreover, ground vibration measurements at numerous sites are exploited for the axle-load spectra and the validation of the prediction method. All theoretical and experimental results confirm that the dynamic axle-load spectra have an approximate value of 1 kN per third of octave and increase with train speed, track stiffness and around the vehicle-track resonance.
Erschütterungen durch Schienenverkehr – Messergebnisse, Quellstärken und Amplituden-Abstands-Gesetze
(1986)
Es werden Messergebnisse und theoretische Studien vorgetragen, die sich mit der Erschütterungsstärke in der Nähe von Bahnlinien und deren Abnahme mit der Entfernung beschäftigen. Durch die Ausdehnung der Anregung über die Zuglänge ergibt sich bei gleichphasiger Anregung ein Bereich konstanter Amplituden, bei zufälliger Phasenlage eine gleichmäßige Abnahme, die schwächer als bei einer Punktlast ist. Die Messungen belegen, dass es eine starke Abnahme für die Vorbeifahrt der statischen Achslasten gibt, so dass dieser Anteil spätestens in 10 m Abstand unbedeutend ist. Am Gleis selbst ist dieser (statische) Anteil dominant.
Das Ziel der Untersuchungen ist ein Prognosemodell für Erschütterungen infolge Schiennahverkehr. Ergänzend zu Bericht 9 wird insbesondere der dreidimensionale, instationäre und zufällige Charakter der Erschütterungsquelle und dessen Auswirkungen auf die Ausbreitung durch den Boden und auf die Schwingungen benachbarter Gebäude untersucht. Es werden jeweils theoretisch/numerisch und experimentell/messtechnisch
- Amplituden-Abstands-Gesetze,
- Freifeld-Bauwerks-Übertragungsverhältnisse und
- Deckenresonanzüberhöhungen
ermittelt, die zusammen mit den Ergebnissen des Berichts 9 eine realistische Prognose von Erschütterungen ermöglichen. Die Ergebnisse sind in einem einfachen Prognoseprogramm zusammengefasst, mit dem im konkreten Anwendungsfall der Einfluss einer Reihe von Quell-, Boden- und Bauwerkseigenschaften erfasst wird.
Erschütterungsminderung der besohlten Schwelle, Rechenergebnisse zur Auswahl einer Teststruktur
(2012)
Train-induced ground vibration can be excited by wheel and track irregularities and by two kinds of irregularities of the soil, by geometric irregularities or by the spatially varying soil stiffness. For both types of irregularities, the effective track irregularity on top of the track is calculated in wavenumber domain and with wavenumber integrals. For a general multi-beam track model, the wavenumber integrals are solved numerically. The irregularities of the soil are filtered by the track when transferred from the bottom to the top of the track. The high-wavenumber irregularities are strongly reduced due to the bending stiffness of the track and the compliance of the support. In addition, soft track elements reduce directly the stiffness variation of the support. Therefore, the mitigation effect of elastic track elements for these excitation components seems to be important. For under-sleeper pads and slab tracks, calculation and measurements are presented including additional excitation components and the dynamic vehicle–track interaction, and the relevance of the excitation mechanisms is discussed based on the dynamic forces which are acting on the ground. Due to the restricted amplitudes, the parametric excitation by the stiffness variation seems to be less important than the geometric irregularities. The calculations yield the correct trends of the measurements and many details of the measured ballast, slab, and under-sleeper-pad tracks.
Fahrzeug-Fahrweg-Untergrund-Umgebung: Theoretische, rechen- und messtechnische Untersuchungen
(1987)
Fahrzeug-Fahrweg-Untergrund-Umgebung: theoretische, rechnen- und meßtechnische Untersuchungen
(1987)
The computation of the wave propagation in homogeneous and layered soils can be performed by a numerical integration in wavenumber domain. The numerical difficulties of an infinite integral and an integrand with poles can be solved. But if this computation must be repeated for many distances, many frequencies, many loads, or many soil models, it becomes a time consuming task which is not acceptable for a user-friendly prediction tool for railway induced ground vibration. Therefore, an approximate method for the computation of the wave field has been developed. The computation consists of several steps. At first, an approximate dispersion profile is calculated according to rules which have been derived from exact solutions. Secondly, the dispersion is used to achieve the amplitude for a certain frequency and a certain distance by calculating the approximate solution of a corresponding homogeneous half-space. Thirdly, three layer corrections are added which include lowfrequency near-field effects, high-frequency far-field effects, and a resonance amplification around the layer frequency. This procedure yields the wave field due to a point load. For a train load, many of these point-load responses have to be summed up, and a frequencydependant reduction factor has to be multiplied to incorporate the effect of the load distribution along and across the track. - The prediction method is applied to real sites, and the appropriate soil models are identified by approximating the measured transfer functions (frequency-dependant amplitudes) which is presented as an alternative to the approximation of the dispersion (frequency-dependant wave velocities). These examples demonstrate the general behavior of layered soils: the low amplitudes of the stiff half-space at low frequencies, the high amplitudes of the softer layer at high frequencies, the strong increase of amplitudes and a possible resonance amplification at mid frequencies. The material damping of the layer yields a strong attenuation of the amplitudes with the distance for high frequencies. The response depends strongly on the resonance or layer frequency which is shown for different layer depths and velocities always in good agreement with measurements. The layer frequency can be of immense influence if train-speed effects are analysed in a layered soil. The good agreement with many measurements in this contribution as well as in the references validates the prediction of ground vibration based on the theory of a layered half-space.
Methods have been presented for detailed studies of railway vibration and for the fast prediction of train-induced ground vibration. The ground vibration is generated by static or dynamic loads. The main purpose of this contribution was to show the influence of inhomogeneous soils on the different vibration components.
Layered soils, namely a soft layer on a stiffer half-space, yield a quite specific transmission behavior. The low-frequency and sometimes also high-frequency cut-off of the transfer function of the soil is demonstrated in theory and by experiments at many sites of which the soil model is approximated from dispersion and transfer function measurements. The layer frequency divides the frequency range in a low-frequency range, where the stiff half-space rules the low amplitudes, and a high amplitude high-frequency range which is mainly determined by the softer top layer. A thick soft layer yields a very low layer frequency, so that the higher soft soil amplitudes have a wider range down to low frequencies. A thin layer yields a high layer frequency, so that the high frequencies above this layer frequency are dominant. The higher the contrast between the stiff half-space and the soft layer is, the stronger the increase between the half-space and layer amplitudes, the more characteristic are the spectra of the soil transfer function. The range of measured soils has been from vS1 down to 125 m/s, vS2 up to 1000 m/s and the layer frequencies are within 10 Hz < f0 < 75 Hz. Moreover, during this measuring campaign in Switzerland, all 11 sites showed clearly the layer-on-half-space behaviour. The transfer functions of inhomogeneous soils have been used to predict the ground vibration due to dynamic axle loads which is usually thought to be the most important component.
The passage of static loads, in the contrary, results in very small vibration amplitudes for low train speeds, which can only be found at near distances and at low frequencies. They attenuate very rapidly with distance and lose very rapidly the higher frequency content. The passage of static axle loads can be included in the prediction of railway vibration just for completeness.
Special attention should be given to the case if the train runs with the Rayleigh-wave speed of the soil (Rayleigh train). The Rayleigh-train effect is strongest for a homogeneous half-space: At the near-field of the track the amplitudes are raised strongly compared to normal trains, and in addition, little attenuation with distance is observed. In case of a layered soil, the low-frequency cut-off reduces the frequency range and the amplitudes of the homogeneous quasi-static ground vibrations. Therefore, the Rayleigh-train effects are clearly reduced by a layered soil and they disappear if the layer frequency (for example for a thin layer) is higher than the frequency band of the axle impulse. The Rayleigh-train effect could completely disappear in a randomly inhomogeneous soil, but this has not been analysed so far.
The axle impulses from static loads can have an additional, quite different effect. They can be scattered by a randomly inhomogeneous soil so that a part (the scattered part) of the axle impulse can reach further distances from the track. This can establish a certain mid-frequency component of the ground vibration which becomes dominant in the far-field, and this important component exists for all train speeds. Experimental results from BAM and international measurements show the importance of the corresponding frequency range.
The mitigation of train induced ground vibration by elastic and stiff track elements has been analysed threefold. The vehicle-track interaction yields the reduction at high frequencies above the vehicle-track resonance. This is the standard effect. The filtering of trackbed errors by the bending stiffness of the track yields a certain mid-frequency effect. An even stronger mid-frequency effect is predicted for the mitigation of the scattered axle impulses by the bending stiffness and elastic elements of the track.
The reduction of train-induced ground vibration by elastic elements such as rail pads and sleeper pads has been analyzed by a combined finite-element boundary-element method. The dynamic compliance of the track, the transfer function of the total force on the ground and the ground vibration ratios have been calculated for a variety of isolated and un-isolated track systems. It has been found that the soil force transfer, which describes the excitation force of the soil, is an appropriate quantity to predict the reduction of the ground vibration and the effectiveness of isolated tracks. All force transfer functions of isolated tracks display a vehicletrack resonance where the wheelset on the compliant track is excited by wheel and track irregularities. At higher frequencies, considerable reductions of the amplitudes are observed as the benefit of the resilient element. The influence of the stiffness of the rail or sleeper pads, the ballast and the soil, and the mass of the sleeper and the wheelset on the resonance frequency and the reduction has been investigated. Sleeper pads are advantageous due to the higher mass that is elastically supported compared to the rail-pad track system. The combination of elastic rail and sleeper pads has been found to be disadvantageous, as the second resonance occurs in the frequency range of intended reduction.
Mitigation measures of railway induced vibration have been demonstrated at the emission, transmission and immission part. It must be carefully observed that the correct masses and stiffnesses are used.
Typical mistakes have been shown,
- 1D models for vehicle-track interaction,
- impedance instead of stiffness for the infill material of a trench,
- rigid buildings or neglecting the soil-building interaction.
The dominant mid-frequency part of the ground vibration is due to the irregular soil.
Die Prognose und Minderung von Bahnerschütterungen haben eine lange Tradition in der Bundesanstalt für Materialforschung und -prüfung. Im Jahr 2006 wurde eine Prognose-Software fertiggestellt, die viele Forschungs- und Messergebnisse zusammenfasst. Sie umfasst die Teilbereiche Emission (die Anregung durch die Fahrzeug-Fahrweg-Untergrund-Wechselwirkung), die Transmission (die Ausbreitung durch den Boden) und die Immission (die Übertragung vom Freifeld in ein Gebäude). Die Prognose geschieht in allen Teilen mit einfachen Formeln, die veröffentlicht sind und zur Anwendung für Jedermann zur Verfügung stehen. Es werden Beispiele zur Emission und zur Transmission gezeigt.
Im Bereich Transmissionsprognose werden zu den Anregungskräften (aus dem Emissionsteil) die Bodenerschütterungen als Schwinggeschwindigkeitsterzspektren berechnet. Das Ergebnis hängt stark von der Bodensteifigkeit, -dämpfung und -schichtung ab. Dies wurde später mit einer Messkampagne in der Schweiz an 10 Messorten bestätigt (Bild 1). Die Berechnung erfolgt näherungsweise für einen geschichteten Boden mit einer frequenzabhängigen Wellengeschwindigkeit (Dispersion) oder einem tiefenabhängigen Wellengeschwindigkeitsprofil.
Die Anregungskräfte werden im Prognosebereich Emission mit einem 2-dimensionalen Gleismodell berechnet (Bild 2). 1-dimensionale Modelle liefern meist falsche Ergebnisse und 3-dimensionale Modelle (zum Beispiel mit der kombinierten Finite-Element-Randelement-Methode) sind für eine Erschütterungs¬prognose sicherlich zu aufwändig. Das 2-dimensionale Modell wurde an 3-dimensionale Ergebnisse so angepasst, dass die Ergebnisse für viele Gleise und Böden annähernd zutreffen. Auch Minderungs¬maßnahmen am Gleis können mit diesem Modell sehr gut berechnet werden.
Die Prognoseverfahren wurden in den folgenden Jahren weiter verfeinert. Es wurde die quasi-statische Anregung durch die bewegten statischen Zuglasten mit einer Näherungsformel ergänzt, so dass auch das tieffrequente Nahfeld realistisch erfasst werden kann. Mit der Berücksichtigung der Achsfolge (insbesondere zwischen den Achsen im Drehgestell) ergeben sich zwei typische Minima in den Erschütterungsspektren, die oft auch in den Messungen beobachtet werden. Der Amplitudenanteil zwischen diesen beiden Minima ist oft stärker angehoben, so dass hier eine zusätzliche Erschütterungsanregung vermutet wird. Dieser Anteil kann rein empirisch prognostiziert werden, so wie das in den englischen Prognosen (zuletzt für das Highspeed2-Projekt) enthalten ist. Die Begründung dieses Anteils ist allerdings nicht die Achsfolge, sondern die Zerstreuung der statischen Achslastimpulse durch einen unregelmäßigen Gleisuntergrund und Boden.
Die messtechnische Ermittlung eines Minderungseffektes ist komplizierter als allgemein angenommen. Es reicht nicht aus, jeweils an einem Messpunkt in der Nähe eines Gleises mit und ohne Minderungs¬maßnahme die Erschütterungen zu messen und aus dem Verhältnis der Amplituden (beziehungsweise aus der Differenz der Pegel) „die Einfügedämmung“ zu ermitteln. Es wird an Beispielen gezeigt, wie man hier sinnvoller vorgehen kann.
1. Zunächst ist es wichtig, nicht nur die Einfügedämmung sondern auch die Originalspektren mit und ohne Minderung zu dokumentieren und zu veröffentlichen, damit man kontrollieren kann, ob wesentliche Amplituden und Frequenzbereiche reduziert sind oder ob es sich um eher zufällige Minderungen oder Verstärkungen handelt. (Beispiel Unterschottermatte/Raron, Müller/SBB)
2. Der Messpunkt sollte nicht im Nahbereich des Gleises liegen, da ansonsten eine zu günstige, falsche Einfügedämmung bestimmt wird. (Beispiel Tunnel/ Leipzig/Breitsamter)
3. Um Zufälligkeiten zu vermeiden, sollte man an mehr als einem Punkt messen. (Beispiel Unterschotterplatte/Altheim/Auersch)
4. Man sollte eigentlich immer auch die Bodenkennwerte (Steifigkeit, Dämpfung, Amplituden-abnahme, Übertagungsfunktion) messen. Selbst bei nahegelegene Messquerschnitten kann man Überraschungen erleben. (Beispiel erste ICE-Messungen/bei Würzburg/Auersch)
5. Bei verschiedenen Bodenkennwerten kann man eine Korrektur durchführen. (Beispiel Gleis-tröge/Mistler) Am besten bestimmt man ein äquivalentes Kraftspektrum zu jedem Messort und jedem Messzug (Beispiel Feste Fahrbahn/Gardelegen/Auersch)
6. Prinzipiell gibt es nicht die Einfügedämmung einer Maßnahme. Die Einfügedämmung ist immer boden- und referenzsystemabhängig. Die „beste“ Einfügungsdämmung erhält man mit einem steifen Untergrund (Beispiel Unterschottermatte/Tunnel/München Gasteig/Wettschureck) Das heißt aber nicht, dass die Maßnahme durch einen künstlich versteiften Untergrund besser wird (Beispiel Unterschottermatten/RRT2006/Auersch)
Es werden Messbeispiele gezeigt, die alle neben einer hochfrequenten dynamischen Minderung auch eine mittelfrequente quasi-statische Minderung aufweisen. Dabei wird der mittelfrequente Zerstreuanteil der statischen Achslastimpulse durch die breitere Lastverteilung und damit die Impulsdehnung der Achslastimpulse reduziert. Diese Impulsdehnung lässt sich mit dem 2-dimensionalen Gleismodell berechnen. Die Minderungswirkung hängt aber wiederum vom Referenzsystem und dessen unregel¬mäßiger Steifigkeitsverteilung ab. Je unregelmäßiger der Boden und Gleisuntergrund des Referenz¬systems, desto stärker ist die Minderungswirkung.
Die Prognose und Minderung von Bahnerschütterungen haben eine lange Tradition in der Bundesanstalt für Materialforschung und -prüfung. Im Jahr 2006 wurde eine Prognose-Software fertiggestellt, die viele Forschungs- und Messergebnisse zusammenfasst. Sie umfasst die Teilbereiche Emission (die Anregung durch die Fahrzeug-Fahrweg-Untergrund-Wechselwirkung), die Transmission (die Ausbreitung durch den Boden) und die Immission (die Übertragung vom Freifeld in ein Gebäude). Die Prognose geschieht in allen Teilen mit einfachen Formeln, die veröffentlicht sind und zur Anwendung für Jedermann zur Verfügung stehen. Es werden Beispiele zur Emission und zur Transmission gezeigt. Im Bereich Transmissionsprognose werden zu den Anregungskräften (aus dem Emissionsteil) die Bodenerschütterungen als Schwinggeschwindigkeitsterzspektren berechnet. Das Ergebnis hängt stark von der Bodensteifigkeit, -dämpfung und -schichtung ab. Dies wurde später mit einer Messkampagne in der Schweiz an 10 Messorten bestätigt. Die Berechnung erfolgt näherungsweise für einen geschichteten Boden mit einer frequenzabhängigen Wellengeschwindigkeit (Dispersion) oder einem tiefenabhängigen Wellengeschwindigkeitsprofil. Die Anregungskräfte werden im Prognosebereich Emission mit einem 2-dimensionalen Gleismodell berechnet. 1-dimensionale Modelle liefern meist falsche Ergebnisse und 3-dimensionale Modelle (zum Beispiel mit der kombinierten Finite-Element-Randelement-Methode) sind für eine Erschütterungs¬prognose sicherlich zu aufwändig. Das 2-dimensionale Modell wurde an 3-dimensionale Ergebnisse so angepasst, dass die Ergebnisse für viele Gleise und Böden annähernd zutreffen. Auch Minderungs¬maßnahmen am Gleis können mit diesem Modell sehr gut berechnet werden. Die Prognoseverfahren wurden in den folgenden Jahren weiter verfeinert. Es wurde die quasi-statische Anregung durch die bewegten statischen Zuglasten mit einer Näherungsformel ergänzt, so dass auch das tieffrequente Nahfeld realistisch erfasst werden kann. Mit der Berücksichtigung der Achsfolge (insbesondere zwischen den Achsen im Drehgestell) ergeben sich zwei typische Minima in den Erschütterungsspektren, die oft auch in den Messungen beobachtet werden. Der Amplitudenanteil zwischen diesen beiden Minima ist oft stärker angehoben, so dass hier eine zusätzliche Erschütterungsanregung vermutet wird. Dieser Anteil kann rein empirisch prognostiziert werden, so wie das in den englischen Prognosen (zuletzt für das Highspeed2-Projekt) enthalten ist. Die Begründung dieses Anteils ist allerdings nicht die Achsfolge, sondern die Zerstreuung der statischen Achslastimpulse durch einen unregelmäßigen Gleisuntergrund und Boden. Die messtechnische Ermittlung eines Minderungseffektes ist komplizierter als allgemein angenommen. Es reicht nicht aus, jeweils an einem Messpunkt in der Nähe eines Gleises mit und ohne Minderungsmaßnahme die Erschütterungen zu messen und aus dem Verhältnis der Amplituden (beziehungsweise aus der Differenz der Pegel) „die Einfügedämmung“ zu ermitteln. Es wird an Beispielen gezeigt, wie man hier sinnvoller vorgehen kann. 1. Zunächst ist es wichtig, nicht nur die Einfügedämmung sondern auch die Originalspektren mit und ohne Minderung zu dokumentieren und zu veröffentlichen, damit man kontrollieren kann, ob wesentliche Amplituden und Frequenzbereiche reduziert sind oder ob es sich um eher zufällige Minderungen oder Verstärkungen handelt. (Beispiel Unterschottermatte/Raron, Müller/SBB) 2. Der Messpunkt sollte nicht im Nahbereich des Gleises liegen, da ansonsten eine zu günstige, falsche Einfügedämmung bestimmt wird. (Beispiel Tunnel/ Leipzig/Breitsamter) 3. Um Zufälligkeiten zu vermeiden, sollte man an mehr als einem Punkt messen. (Beispiel Unterschotterplatte/Altheim/Auersch) 4. Man sollte eigentlich immer auch die Bodenkennwerte (Steifigkeit, Dämpfung, Amplituden-abnahme, Übertagungsfunktion) messen. Selbst bei nahegelegene Messquerschnitten kann man Überraschungen erleben. (Beispiel erste ICE-Messungen/bei Würzburg/Auersch) 5. Bei verschiedenen Bodenkennwerten kann man eine Korrektur durchführen. (Beispiel Gleis-tröge/Mistler) Am besten bestimmt man ein äquivalentes Kraftspektrum zu jedem Messort und jedem Messzug (Beispiel Feste Fahrbahn/Gardelegen/Auersch) 6. Prinzipiell gibt es nicht die Einfügedämmung einer Maßnahme. Die Einfügedämmung ist immer boden- und referenzsystemabhängig. Die „beste“ Einfügungsdämmung erhält man mit einem steifen Untergrund (Beispiel Unterschottermatte/Tunnel/München Gasteig/Wettschureck) Das heißt aber nicht, dass die Maßnahme durch einen künstlich versteiften Untergrund besser wird (Beispiel Unterschottermatten/RRT2006/Auersch) Es werden Messbeispiele gezeigt, die alle neben einer hochfrequenten dynamischen Minderung auch eine mittelfrequente quasi-statische Minderung aufweisen. Dabei wird der mittelfrequente Zerstreuanteil der statischen Achslastimpulse durch die breitere Lastverteilung und damit die Impulsdehnung der Achslastimpulse reduziert. Diese Impulsdehnung lässt sich mit dem 2-dimensionalen Gleismodell berechnen. Die Minderungswirkung hängt aber wiederum vom Referenzsystem und dessen unregelmäßiger Steifigkeitsverteilung ab. Je unregelmäßiger der Boden und Gleisuntergrund des Referenzsystems, desto stärker ist die Minderungswirkung.
Dieser Bericht gliedert sich in drei Abschnitte, in denen der Einfluß inhomogener Böden auf die Dynamik von Verkehrssystemen untersucht wird. In erster Linie werden dabei geschichtete Böden behandelt, für die ein Rechenverfahren entwickelt wurde. Als elementares Ergebnis werden die Wellenfelder geschichteter Böden bei einer punktförmigen Belastung dargestellt. Mit diesen Punktlastlösungen können dann die Schwingungen von starren oder flexiblen Strukturen auf geschichteten Böden berechnet werden. Es wird die dynamische Steifigkeit und Dämpfung starrer Fundamentflächen dargestellt, an der das stark frequenzabhängige Verhalten geschichteter Böden besonders deutlich wird.
The propagation of waves through homogeneous or layered soil is calculated based on half-space theory. The moving dynamic loads of a train are approximated by fixed dynamic loads and the wave field can be calculated if the spectrum of the dynamic train loads is known. In addition to this dynamic wave field, there are three different components at three different frequency ranges which are caused by the passage of the static loads:
the regular static component at low frequencies,
the irregular static component at medium frequencies,
the sleeper-passing component at high frequencies.
For each of these components, an approximate solution is presented. The calculated wave field is compared with measurements of different trains at different sites. The measurement of impulse and harmonic point load excitation verifies the soil dynamic base of the method.
The Federal Institute of Material Research and Testing has performed many impact tests from very small laboratory tests to very big “free-field” tests with heavy containers on stiff foundations. The first measurements have been done on a big foundation where it should be guaranteed that the foundation is rigid and the container is tested properly. Later on, a smaller drop test facility has been built on the ground inside an existing building. It had to be controlled by prediction and measurements that the drop test will not damage the building. Tests from different heights on soft, medium, and stiff targets have been done to find out rules which allow to identify acceptable and unacceptable drop tests. Later on, the biggest drop test facility has been built for masses up to 200 t. It was necessary for the design of the foundation to estimate the forces which oc-cur during the drop tests. In addititon, the acceptable tests should be selected and controlled by measurements where the impact duration is important. Dif-ferent sensors, accelerometers, accelerometers with mechanical filters, geo-phones (velocity transducers), strain gauges, and pressure cells have been ap-plied for these tasks. Signal transformations and model calculations have been used to check and understand the dynamic measurements. The simplest law is the conservation of the momentum which is a good approximation if the impact is short. If the soil under the foundation has an influence on the deceleration of the container, the maximum foundation velocity is lower than the simple esti-mation.
The Federal Institute of Material Research and Testing has performed many impact tests from very small laboratory tests to very big “free-field” tests with heavy containers on stiff foundations. The first measurements have been done on a big foundation where it should be guaranteed that the foundation is rigid and the container is tested properly. Later on, a smaller drop test facility has been built on the ground inside an existing building. It had to be controlled by prediction and measurements that the drop test will not damage the building. Tests from different heights on soft, medium, and stiff targets have been done to find out rules which allow to identify acceptable and unacceptable drop tests. Later on, the biggest drop test facility has been built for masses up to 200 t. It was necessary for the design of the foundation to estimate the forces which oc-cur during the drop tests. In addititon, the acceptable tests should be selected and controlled by measurements where the impact duration is important. Dif-ferent sensors, accelerometers, accelerometers with mechanical filters, geo-phones (velocity transducers), strain gauges, and pressure cells have been ap-plied for these tasks. Signal transformations and model calculations have been used to check and understand the dynamic measurements. The simplest law is the conservation of the momentum which is a good approximation if the impact is short. If the soil under the foundation has an influence on the deceleration of the container, the maximum foundation velocity is lower than the simple esti-mation.
The maintenance of the transport infrastructures and their further development are going to remain focal points for investment and research in Germany in future. According to the latest development forecasts made by both the federal government and Deutsche Bahn, even if rail´s percentage share of the market were to remain unchanged, growth of around 50% would be expected in the next ten years, especially in freight traffic. This growth is necessitating considerable development both in the technical design of the tracks and in the abatement of the noise and vibration caused by railway traffic.
Der Erhalt und die Weiterentwicklung der Verkehrsinfrastrukturen werden auch zukünftig einen Investitions- und Forschungsschwerpunkt in Deutschland bilden. Gemäß den aktuellen Entwicklungsprognosen sowohl der Bundesregierung als auch der Deutschen Bahn wäre bei unveränderten Marktanteilen der Bahn eine Zunahme insbesondere des Güterverkehrs in den kommenden 10 Jahren um ca. 50% zu erwarten. Dieser Zuwachs erfordert erhebliche Entwicklungen sowohl in der technischen Konstruktion der Fahrwege als auch im Erschütterungs- und Lärmschutz infolge des Schienenverkehrs.
Cet article présente plusieurs modèles numériques pour létude des phénomènes vibratoires lors du passage dun train. Les modèles permettent destimer la propagation des ondes et les réceptances pour le sol et la voie. Le sol multicouche et le couplage voie-sol sont traités par une (double) intégration sur les nombres donde. Les raideurs dynamiques de la voie et du véhicule sont combinées et les forces dexcitation roue-rail dues aux irrégularités de la voie et des roues sont calculées. Ces forces dexcitation permettent de simuler les vibrations du sol lors du passage dun train. Les modèles sont validés par comparaison avec des mesures sur deux sites, en France et en Allemagne. Les vibrations calculées correspondent bien aux vibrations mesurées. ----------------------------------------------------------------------------------------------------
This contribution presents models that are necessary to calculate the vibrations due to the passage of a train. The models allow to calculate the propagation of the waves and the receptances of the soil and the track. The layered soil and the coupling with the track are treated by a (double) integration in wavenumber domain. The dynamic stiffnesses of the track and vehicle are combined and the excitation forces due to the irregularities of the track and the wheel are calculated. Finally, these excitation forces are used to simulate the ground vibration of a passing train. All these models are validated by a number of different measurements at two sites in France and Germany.
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.
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.
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.
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.
Measurements of downburst wind loading acting on an overhead transmission line in northern Germany
(2017)
Along an overhead transmission line in Northern Germany, a unique instrumentation of anemometers and force measurements is installed. Details of this test line with wind measurements along a horizontal axis are given. A recent event of a presumable downburst wind event is analyzed by means of available data and precedent works on thunderstorm analysis. The measured response of the conductors at the suspension tower is investigated and compared with time domain simulation of a finite element model.
Measurements on the vehicle-track interaction and the excitation of railway-induced ground vibration
(2017)
Two railway measurement campaigns have been performed in Germany and Switzerland which yield insight in the vehicle-track-soil interaction. The campaign in Germany has included simultaneous measurement of vehicle, track, and soil vibrations during train runs with 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. Two ballast tracks, one on the soil surface and one on a concrete bridge, have been investigated as well as a slab track in a tunnel. Ten different sites in Switzerland have been measured for soil properties and train-induced ground vibrations, which allow to determine the excitation forces of the railway traffic. New axle-box measurements at some of the Swiss sites have been analysed to get further experimental evidence. All these measurements have been evaluated to characterize the excitation processes. Relations between vehicle vibration and ground vibration can be observed. The vehicle vibrations, namely the accelerations of the wheelsets, yield the dynamic forces due to the passage over the irregularities of the vehicle and the track. The ground vibrations are correlated to these dynamic forces to a certain extent. Some mid-frequency ground vibration amplitudes, however, are higher than expected from the dynamic excitation forces. The experimental observations can be explained by an irregular response to the passage of the static loads, that means the passage of the static loads over an irregular ballast or soil. This correct understanding of the excitation processes is important for the prediction as well as for the mitigation of railway induced ground vibrations.
Measurements on the vehicle-track interaction and the excitation of railway-induced ground vibration
(2017)
Two railway measurement campaigns have been performed in Germany and Switzerland which yield insight in the vehicle-track-soil interaction. The campaign in Germany has included simultaneous measurement of vehicle, track, and soil vibrations during train runs with 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. Two ballast tracks, one on the soil surface and one on a concrete bridge, have been investigated as well as a slab track in a tunnel. Ten different sites in Switzerland have been measured for soil properties and train-induced ground vibrations, which allow to determine the excitation forces of the railway traffic. New axle-box measurements at some of the Swiss sites have been analysed to get further experimental evidence. All these measurements have been evaluated to characterize the excitation processes. Relations between vehicle vibration and ground vibration can be observed. The vehicle vibrations, namely the accelerations of the wheelsets, yield the dynamic forces due to the passage over the irregularities of the vehicle and the track. The ground vibrations are correlated to these dynamic forces to a certain extent. Some mid-frequency ground vibration amplitudes, however, are higher than expected from the dynamic excitation forces. The experimental observations can be explained by an irregular response to the passage of the static loads, that means the passage of the static loads over an irregular ballast or soil. This correct understanding of the excitation processes is important for the prediction as well as for the mitigation of railway induced ground vibrations.
A survey of the phenomena and methods for floor vibrations is presented. Experimental results of floor vibrations are shown for many floors in six different buildings. The signals have been evaluated for waves and modes by simple procedures. General rules have been established between the material and the area of a specific floor, and its local eigenfrequency. The damping values of the floor vibrations have been found between D = 1 and 10 % where somewhat higher values have been measured for wooden floors, and a weak correlation with the eigenfrequency has been established. The velocities of bending waves propagating in a storey and the attenuation with distance in the building have been analysed. A considerable transfer of vibration from one room to far away parts of the building has been found in the studied buildings with concrete and wooden floors. An example building has been analysed for modes of coupled floor bays. The strong coupling of similar neighbouring floor bays would yield a wide band of global resonance frequencies. The measured wooden floor exhibits a weak coupling of the neighbouring floor bays and a narrower band of eigenfrequencies. A special method has been tested with the impulse measurements to estimate the coupled eigenmodes in presence of the high damping. From the ambient measurement, a low-frequency vibration mode has been detected which includes the vibration of the whole building and the soil. The coupling of floors to other floors and the whole building is an important phenomenon of structural dynamics which should be observed for the prediction of vibration due to internal and external sources.
The ground vibrations, which are generated by trains on different tracks, have been calculated by finite-element boundary-element models. The ballasted track is modelled in detail by the finite element method. The infinite soil is modelled by the boundary element method as a homogeneous or layered half-space. The track-soil system is coupled to a simple rigid mass model of the vehicle so that the vehicle-track interaction is completely included. Transfer functions are calculated in frequency domain without and with vehicle-track interaction, the compliance of the track and the mobilities of the soil at different distances from the track. Finally, the ratios between the ground vibration amplitudes with and without mitigation measures are calculated to quantify the effectiveness of the mitigation measures.
Tracks with under-sleeper pads have been investigated in a wide parameter study for the RIVAS project. The main parameters that influence the reduction of ground vibration are the stiffness of the under-sleeper pad, the mass and the width of the sleeper. The softest sleeper pad yields the best reduction of the ground vibration. The influence of the sleeper mass is not so strong, as the characteristic frequency is ruled by the mass of the sleeper and the mass of the wheelset as well.
The ground vibrations, which are generated by trains on different tracks, have been calculated by finite-element boundary-element models. The ballasted track is modelled in detail by the finite element method. The infinite soil is modelled by the boundary element method as a homogeneous or layered half-space. The track-soil system is coupled with a simple rigid mass model of the vehicle so that the vehicle-track interaction is completely included. Transfer functions are calculated in frequency domain without and with vehicle-track interaction, the compliance of the track and the mobilities of the soil at different distances from the track. Finally, the ratios between the ground vibration amplitudes with and without mitigation measure are calculated to quantify the effectiveness of the mitigation measure.
Tracks with under sleeper pads have been investigated in a wide parameter study. The main parameters that influence the reduction of ground vibration are the stiffness of the under sleeper pad, the mass and the width of the sleeper. The softest sleeper pad yields the best reduction of the ground vibration. The influence of the sleeper mass is not as strong as the characteristic frequency is ruled by the mass of the sleeper and the mass of the wheelset as well.
The influence of other parameters has been examined. The stiffness of the rail pads, the bending stiffness of the track, the stiffness of the ballast, the sub-soil, and the soil, and the layering of the soil. All these parameters show no or only a minor influence on the mitigation effect.
As the standard isolated track, a track with an under sleeper pad of a stiffness of kS = 5 107 N/m has been chosen, which can also be expressed as a stiffness per area of kS ’’ = 7.4 107 N/m3 = 0.074 N/mm3.
The resonance frequency for this pad stiffness is observed between 32 and 40 Hz. The reduction of the ground vibration is about vi,I /vi,U = 0.2 and 0.1 at 100 Hz. The reduction can be improved by softer sleeper pads. But the compliance of the track gets higher than tolerable. A possibility to use softer sleeper pads without increasing the static compliance of the track is their combination with wide sleepers. The softer sleeper pads under wider sleepers yield the same compliance of the track and a better reduction of the ground vibration.
The ground vibrations, which are generated by trains on different slab tracks, have been calculated by finite-element boundary-element models. The slab track is modelled in detail by the finite element method.
The infinite soil is modelled by the boundary element method as a homogeneous half-space. The track-soil system is coupled with a simple rigid mass model of the vehicle so that the vehicle-track interaction is completely included. Transfer functions are calculated in frequency domain without and with vehicle-track interaction, the compliance of the track and the mobilities of the soil at different distances from the track.
Finally, the ratios between the ground vibration amplitudes with and without mitigation measure are calculated to quantify the effectiveness of the mitigation measure.
Tracks with under sleeper pads have been investigated in a parameter study. The main parameter that influences the reduction of ground vibration is the stiffness of the under sleeper pad. The softest sleeper pad yields the best reduction of the ground vibration.
The influence of other parameters has been examined. The stiffness of the rail pads, the stiffness of the slab material, the stiffness of the sleeper material, and the distance of the sleepers. All these parameters show no or only a minor influence on the mitigation effect.
As the standard isolated track, a track with an under sleeper pad of a stiffness of kS = 5 107 N/m has been chosen, which can also be expressed as a stiffness per area of kS ’’ = 3.7 107 N/m3 = 0.037 N/mm3.
The resonance frequency for this pad stiffness is observed between 32 and 40 Hz. The reduction of the ground vibration is about vi,I /vi,U = 0.1 at 100 Hz.
This contribution presents some principles and some examples of the mitigation of railway-induced ground vibrations. The principles are different for the mitigation measures at the track, in the soil or at the building. Force transfer functions of isolated and un-isolated track-soil systems, reflected and transmitted wave amplitudes at walls and trenches in the soil, and the transfer of the (free-field) vibration amplitudes to the foundation amplitudes of the building are analysed. The mitigation effect can be calculated by exact or simplified formulas. Some examples with 3D (finite-element boundary-element), 2D (beam-on-support), and 1D track models, 2D and 1D soil models, detailed 3D building models and finite or infinite 1D wall-floor models are investigated to find out if simple models can be used for a satisfactory prediction of the mitigation effect. The 1D track examples show that the force transfer of the track without vehicle can be exactly calculated, whereas the total force transfer can be calculated approximately if appropriate wheelset masses per track length are used for the isolated and the un-isolated track. The mitigation effect of a filled trench is calculated by a 2D finite element model and the results compare with simple transmission formula if the stiffness per area rather than the wave impedances are used for the infill material. The base isolation of a building is analysed by a detailed 3D model and the results are similar to the analytic results of a single wall with floors on the soil. Other reduction measures as different floor and column dimensions are usually less effective so that the clearly best mitigation solution at a building is a partly or a complete base isolation.
This contribution presents some principles and some examples of the mitigation of railway-induced ground vibrations. The principles are different for the mitigation measures at the track, in the soil or at the building. Force transfer functions of isolated and un-isolated track-soil systems, reflected and transmitted wave amplitudes at walls and trenches in the soil, and the transfer of the (free-field) vibration amplitudes to the foundation amplitudes of the building are analysed. The mitigation effect can be calculated by exact or simplified formulas. Some examples with 3D (finite-element boundary-element), 2D (beam-on-support), and 1D track models, 2D and 1D soil models, detailed 3D building models and finite or infinite 1D wall-floor models are investigated to find out if simple models can be used for a satisfactory prediction of the mitigation effect. The 1D track examples show that the force transfer of the track without vehicle can be exactly calculated, whereas the total force transfer can be calculated approximately if appropriate wheelset masses per track length are used for the isolated and the un-isolated track. The mitigation effect of a filled trench is calculated by a 2D finite element model and the results compare with simple transmission formula if the stiffness per area rather than the wave impedances are used for the infill material. The base isolation of a building is analysed by a detailed 3D model and the results are similar to the analytic results of a single wall with floors on the soil. Other reduction measures as different floor and column dimensions are usually less effective so that the clearly best mitigation solution at a building is a partly or a complete base isolation.
Long wooden floor beams above a ball room in an old historical palace have been analysed experimentally. The eleven beams are weakly coupled by three layers of floor boards. It has been investigated if the state (the stiffness) of the wooden beams can be determined by vibration measurements of global or preferably local modes. Hammer, heel-drop and ambient excitations have been used. The vibration modes of the structure show dominating local deformations if an impact excitation is applied. This is understood as the positive superposition of several modes which yield the maximum at the excitation point but a cancellation at more distant points. Natural modes have been estimated from these vibration modes by standard and special methods which were necessary for the high damping of the wooden floor. It has been found that all floor beams contribute to each natural mode even for a weak coupling of the beams. In addition to the modal discussion, the impact tests have also been analysed for the wave propagation and amplitude attenuation with distance. The coupling of floor beams has been studied theoretically by an analytic multiple-beam model where the coupling by translational or rotational springs and by a common support motion has been assumed.
Long wooden floor beams above a ball room in an old historical palace have been analysed experimentally. The eleven beams are weakly coupled by three layers of floor boards. It has been investigated if the state (the stiffness) of the wooden beams can be determined by vibration measurements of global or preferably local modes. Hammer, heel-drop and ambient excitations have been used. The vibration modes of the structure show dominating local deformations if an impact excitation is applied. This is understood as the positive superposition of several modes which yield the maximum at the excitation point but a cancellation at more distant points. Natural modes have been estimated from these vibration modes by standard and special methods which were necessary for the high damping of the wooden floor. It has been found that all floor beams contribute to each natural mode even for a weak coupling of the beams. In addition to the modal discussion, the impact tests have also been analysed for the wave propagation and amplitude attenuation with distance. The coupling of floor beams has been studied theoretically by an analytic multiple-beam model where the coupling by translational or rotational springs and by a common support motion has been assumed.
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.
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.
Im Forschungsvorhaben „Praxisgerechtes Prognoseverfahren für Schienenverkehrserschütterungen“ wurde ein Prognoseprogramm entwickelt, das die Erschütterungsemission, -transmission und –immission für verschiedene Bahnen, verschiedene Böden, verschiedene Gebäude und verschiedene Minderungsmaßnahmen prognostizieren und bewerten kann. Es ist gelungen, ein Prognoseverfahren zusammenzustellen, das sowohl wissenschaftlich fundiert als auch einfach handhabbar ist. Die besonderen Merkmale des Prognoseverfahrens sind folgende:
- Das Prognoseprogramm basiert auf physikalischen Modellen.
- Das Programm besitzt klar definierten Schnittstellen zwischen der Emission und der Transmission und zwischen der Transmission und der Immission. Im ersten Fall sind es die auf den Untergrund wirkenden Erregerkräfte von Fahrzeug und Fahrweg, im zweiten Fall sind es die Freifeldamplituden des Bodens.
- Das Prognoseprogramm erlaubt es, Messdaten einzulesen und in physikalisch sinnvoller Weise weiter zu verarbeiten.
Damit sind die gesetzten Ziele für das Prognoseverfahren erfüllt und mit der Implementierung in einem benutzerorientierten Programm übertroffen worden.
Es ist gelungen, ausgehend von komplexen Modellen einfache Modelle zu finden und anzupassen. Hier ist einerseits die vereinfachte Berechnung der Wellenausbreitung im Boden zu nennen, die sowohl für kontinuierlich steifer werdende Böden als auch für geschichtete Böden zutreffende Ergebnisse liefert. Andererseits war die vereinfachte Berechnung der Fahrweg-Boden-Wechselwirkung ein besonderer Erfolg, da sowohl Standardgleise als auch Bundesanstalt für Materialforschung und –prüfung (BAM) Seite 24 Praxisgerechtes Prognoseverfahren für Schienenverkehrserschütterungen Gleise mit Minderungsmaßnahmen (zum Beispiel mit Unterschottermatten) durch allgemeine Gesetzmäßigkeiten erfasst werden konnten.
The present contribution evaluates four measuring series made by the Federal Institute of Material Research and Testing for the relations between train speed and ground vibration amplitudes. This experimental evaluation is supported by the simulation of the train passages at the different sites by using appropriate excitation mechanisms and forces as well as layered soil models which have been derived from impact measurements at each site.
The present contribution evaluates four measuring series made by the Federal Institute of Material Research and Testing for the relations between train speed and ground vibration amplitudes. This experimental evaluation is supported by the simulation of the train passages at the different sites by using appropriate excitation mechanisms and forces as well as layered soil models which have been derived from impact measurements at each site.
The present contribution evaluates four measuring series made by the Federal Institute of Material Research and Testing for the relations between train speed and ground vibration amplitudes. This experimental evaluation is supported by the simulation of the train passages at the different sites by using appropriate excitation mechanisms and forces as well as layered soil models which have been derived from impact measurements at each site.
Some results of our measurements of the Intercity experimental are presented together with simulated results and their interpretation. Three frequeny ranges could be measured and calculated: low frequencies which decrease very rapidly with distance (the quasi-static part), high frequencies (mainly due to the sleeper passage), and a mid-frequency which has the weakest attenuation with distance and is therefore dominant at the far field. Mono-frequent excitations get a wide frequency band due to the Doppler effect of the moving high-speed train.
Prediction of building noise and vibration – 3D finite element and 1D wave propagation models
(2021)
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.
Prediction of building noise and vibration – 3D finite element and 1D wave propagation models
(2021)
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.
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.
In diesem Bericht werden die Berechnungsmethoden für die Transmission der Erschütterungen dargelegt. Da es sich um die Wellenausbreitung im Boden handelt, sind drei große Abschnitte dem Einfluss und den Berechnungsmöglichkeiten verschiedener homogener und geschichteter Böden gewidmet. Dabei kommt ein exaktes aufwändiges Rechenverfahren und daraus abgeleitete einfachere Näherungsverfahren zum Einsatz.
Zum Bodeneinfluss wurden verschiedene homogene und geschichtete Böden exakt berechnet. Daraus wird ein Näherungsverfahren abgeleitet, dass auf der Dispersionsbeziehung v(f) beruht. Die Dispersion einiger Fälle wird exakt berechnet und ein Näherungsverfahren gefunden, mit dem man aus dem Tiefenprofil v(z) die Dispersion v(f) ermitteln kann. Mitden Näherungsverfahren werden die Wellenfelder der verschiedenen Böden nachgerechnet. Es ergeben sich sehr gute Übereinstimmungen mit den exakten Ergebnissen.
Die Zuganregung wird in erster Linie mit ortsfesten dynamischen Achslasten erfasst. Mit der Lastverteilung über die gesamte Zuglänge ergibt sich eine deutlich andere, nämlich schwächere Abnahmegesetzmäßigkeit als für die elementare Punktlast.
Für die Prognose von Schienenverkehrserschütterungen wurden verschiedene Verfahren vorgestellt, die die theoretischen Methoden zur Wellenausbreitung im Boden auf der experimentellen Seite ergänzen.
Dies beginnt bei der notwendigen Ermittlung der Bodenkennwerte für den Prognoseort, das führt weiter zur sehr hilfreichen Bestimmung der Übertragungsfunktion am Prognoseort, und schließlich zur kritischen Verwendung von gemessenen Spektren als Emissionsgröße. Die verschiedenen Verfahren werden anhand der Messungen der ICE 3-und Thalys-Versuchsfahrten bei Gardelegen vorgeführt.
Die wichtigsten Aussagen dieser Untersuchung sind:
– Die Ergebnisse der Schwinger- und Impulsmessungen, die Bodenkennwerte und die Übertragungsfunktionen, Theorie und Messungen stimmen alle sehr gut miteinander überein.
– Es sind gute Prognosen der Schienenverkehrserschütterungen sowohl mit den theoretischen als auch den experimentellen Übertragungsfunktionen möglich (s. Bild 39 im Vergleich zu Bild 40).
– Die Verwendung von gemessenen Schienenverkehrserschütterungen als Emissionsspektrum wird ermöglicht. Sie ist aber an die Kenntnis der Bodenkennwerte am Messort gekoppelt. Mit den Bodenkennwerten am Messort können dann bodenunabhängige Lastspektren als Emissionsgröße berechnet werden.
Damit steht eine Vielfalt von theoretischen und messtechnischen Varianten für die Prognose der Erschütterungsausbreitung im Boden zur Verfügung.
Es wurde ein Prognosemodell für die Bauwerksschwingungen entwickelt.
Es besteht aus einer Gesamtbauwerkswand, die alle Wände und Stützen eines Bauwerks repräsentiert, und aus den Decken in den einzelnen Stockwerken. Das Modell wird stockwerkweise mit Übertragungsmatrizen berechnet.
Hinsichtlich der Decken besteht im Programm die Möglichkeit, die Deckeneigenfrequenz aus den Abmessungen und den Auflagerbedingungen berechnen zu lassen. Die Decken werden dann im Rechenprogramm als Modalmodelle realisiert und an den Deckenauflagern in die Übertragungsmatrizenkette eingebaut.
Aus diesem Komplexmodell des Gebäudes wurde entsprechend den Messerfahrungen ein praxisnäheres Standardmodell abgeleitet. Dazu werden die Wandamplituden aller Stockwerke gemittelt und bei den Decken wird eine gewisse Bandbreite der vorhandenen Deckeneigenfrequenzen unterstellt.
Entsprechend der hohen Bedeutung, den experimentelle Ergebnisse für die Prognose der Erschütterungsimmission haben, wurden sehr viele in der BAM vorhandene Messdaten erneut ausgewertet und darüber hinaus neue Gebäudemessungen durchgeführt. Die Messergebnisse wurden bei der Definition des Standardmodells herangezogen. Außerdem wurde die Auswahl der Fundamentparameter mit den Messerfahrungen abgeglichen. Schließlich geben die Messdaten von etwa 80 Decken wichtige Hinweise auf die richtige Wahl der Deckenparameter Eigenfrequenz und Dämpfung.
Eine Parameterstudie gibt Auskunft über die praktisch vorkommende Bandbreite der einzelnen Parameter und deren Auswirkung auf die Bauwerksamplituden. Die wichtigsten Parameter sind die Bodensteifigkeit und die Deckeneigenfrequenz, die die Abminderung der Gesamtbauwerksamplituden einerseits und die Amplitudenverstärkungen in der Deckenresonanzen andererseits bestimmen. Für diese beiden Parameter ergaben die Untersuchungen wesentliche Hinweise:
Für die Gebäudegründung sind die weicheren oberen Bodenschichten maßgeblich, und die Deckeneigenfrequenzen lassen sich in erster Näherung gut durch eine allseitig gelenkige Lagerung abbilden.
Mit den theoretischen und experimentellen Arbeiten konnte somit ein praxisgerechter Immissionsteil für die Erschütterungsprognose erstellt werden.
Die VDI Richtlinie 3837 enthält detaillierte Angaben zur Erschütterungsemission. Die DIN 45672-3 enthält nur den Tunnel- oder einen Bodenmesspunkt als Ausgangspunkt der Prognose. Die Erschütterungsanregung durch die Fahrzeug-Fahrweg-Wechselwirkung wird beschrieben. Die ERgebnisse der BAM stimmen sehr gut mit dem Prognosekonzept von Highspeed 2 überein. Dies wird an den Punkten 1. Störgrößen, 2. Achsimpulse, 3. Tunnelstrecken aufgezeigt.
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.
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.
Train passages induce static and dynamic forces on the track, the train-induced vibrations propagate through the soil and excite neighbouring buildings. The problem of train vibrations is divided into the parts emission, which is the excitation by railway traffic (the present contribution), transmission, which is the wave propagation through the soil, and immission, which is the transfer into a building, - The calculation of the axle loads are based on the vehicle-track-soil interaction. This interaction uses the dynamic stiffness of the vehicle (the inertia of the wheelset) and the dynamic stiffness of the track-soil System. Based on various time consuming finite-element boundary-element calculations, an approximate track-soil model has been established. The vehicle-track-soil analysis yields several transfer functions between the various geometric or stiffness irregularities and the axle loads of the train. Geometric irregularities of the vehicle (the wheels) and the track (rail surface and track alignment) are the simplest components. Geometric irregularities of the subsoil (trackbed irregularities) have to be transferred to effective irregularities at rail level. The bending stiffness of the track is filtering out the short-wavelength contribution. Stiffness irregularities occur due to random variations in the bailast or the subsoil, which must also be transferred to effective track irregularities, and due to the discrete rail support on sleepers. The axle loads due to the effective track errors from stiffness variations have their specific vehicle-track transfer function. - All necessary formula for the prediction of axle-load spectra will be presented. The prediction method is compared with axle-box measurements at a Standard ballasted track. Moreover, ground Vibration measurements at numerous sites are exploited for the axle-load spectra and the Validation of the prediction method.
Train-induced ground vibrations are generated by static and dynamic axle loads which can be calculated by vehicle-track-soil models and the vehicle and track irregularities. A fast prediction method has been developed which uses approximate transfer functions of layered soils. In the present contribution, this prediction method is used for the inverse calculation of the axle-load spectra from the measured ground vibration. The layered soils of some measuring sites show very differing ground vibration spectra in the amplitude range of 0.0001–1.0 mm/s as a consequence of the soft layer and stiff half-space, differing layer frequencies, as well as the far- and near-field measuring points. The back-calculation, however, yields axle-load spectra within a single order of magnitude around 1 kN. Axle-box measurements confirm the amplitude level of the axle loads. This standard axle-load spectrum can be used for a basic prediction at a new site. The separation of train and site-specific components allows a better evaluation of railway vibrations, for example, of different trains and different tracks. By eliminating the effects of differing soil characteristics, an important mid-frequency component has been found which lies between 8 and 32 Hz depending on the train speed. The origin of this dominant mid-frequency component is discussed using advanced prediction methods like moving constant loads, scattered axle impulses and axle-sequence spectra.