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#### Schlagworte

- Ground vibration (11)
- Railway track (5)
- Finite-element boundary-element method (4)
- Mitigation (4)
- Track damage (4)
- Track-soil interaction (4)
- Field tests (3)
- Finite element method (3)
- Slab track (3)
- Soil-building interaction (3)
- Track vibration (3)
- Train passages (3)
- Vehicle-track interaction (3)
- ground vibration (3)
- mitigation (3)
- railway track (3)
- Axle box measurements (2)
- Bahnerschütterungen (2)
- Ballast track (2)
- Ballast tracks (2)
- Base isolation (2)
- Bodeneigenschaften (2)
- Boundary element method (2)
- Continuously inhomogeneous soils (2)
- Dynamic testing (2)
- Elastische Gebäudelagerung (2)
- Erschütterungsursachen (2)
- Force transfer (2)
- Frequenzbereiche (2)
- Hammer tests (2)
- Layered soil (2)
- Layered soils (2)
- Pile bending stiffness (2)
- Pile foundation (2)
- Railway (2)
- Railway measurement campaign (2)
- Railway vibration (2)
- Rechenmodelle (2)
- Soil properties (2)
- Soil stiffness (2)
- Under-ballast plate (2)
- Wind energy tower (2)
- floor vibration (2)
- modal analysis (2)
- track-soil interaction (2)
- undersleeper (2)
- wave analysis (2)
- 1-D insertion loss (1)
- Acoplamiento Método de los Elementos de Contorno-Método de los Elementos Finitos (1)
- Amplitude-charge weight laws (1)
- Amplitude-distance law (1)
- Amplitude-distance laws (1)
- Assessment (1)
- Axle-load spectra (1)
- Bahnfahrwege (1)
- Bauwerk-Boden-Wechselwirkung (1)
- Blasting charge (1)
- Bodenerschütterungen (1)
- Boundary Element Method-Finite Element Method coupling (1)
- Deckenschwingungen (1)
- Dispersionsmessung (1)
- Downburst (1)
- Drop height (1)
- Dynamic soil-structure interaction (1)
- Eisenbahngleis (1)
- Elastic track elements (1)
- Emission (1)
- Erschütterungsprognose (1)
- Experimental verification (1)
- Explosion (1)
- Explosion-induced ground vibrations (1)
- FEBEM and simplified methods (1)
- Fahrwegschäden (1)
- Filter effect of the soil (1)
- Flexible plate (1)
- Floor amplification (1)
- Foundation reduction (1)
- Frequency-wavenumber method (1)
- Gebäudeschwingungen, Deckenschwingungen, Wellenausbreitung (1)
- Geometric trackbed irregularities (1)
- Ground vibration measurements (1)
- Hammer impact (1)
- Hammerschlag (1)
- Interacción dinámica suelo-estructura (1)
- Laboratory tests (1)
- Mass drop (1)
- Measurement (1)
- Measurements (1)
- Minderung (1)
- Mitigation measures (1)
- Monitoring (1)
- Multi-beam model (1)
- Multi-beam-on-support model (1)
- Non-synoptic wind event (1)
- Overhead transmission line (1)
- Parametric excitation (1)
- Plate-soil interaction (1)
- Prediction (1)
- Prediction of explosion induced ground and building vibration (1)
- Rail pad (1)
- Railway induced ground vibration (1)
- Railway tracks (1)
- Randelementmethode (1)
- Reduction (1)
- Resonancia en edificaciones (1)
- Resonant response (1)
- Schadenserkennung (1)
- Sleeper pad (1)
- Target stiffness (1)
- Track (1)
- Track damage monitoring (1)
- Track deformation (1)
- Track-soil and vehicle-track resonances (1)
- Train configuration (1)
- Train induced ground vibration (1)
- Train passage (1)
- Train speed (1)
- Tran speed (1)
- Under sleeper pads (1)
- Varying track stiffness (1)
- Vibration reduction (1)
- Wave excitation (1)
- Wavenumber integrals (1)
- Wavenumber method (1)
- Wellenfeldberechnung (1)
- Zugüberfahrt (1)
- sleeper pads (1)

#### Organisationseinheit der BAM

- 7 Bauwerkssicherheit (64) (entfernen)

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.

Durch Schienenverkehr angeregte Wellenausbreitung durch den Boden - Stand der Simulationsmethoden
(2014)

The Federal Institute of Material Research and Testing (BAM) has collected some experience with the testing of damaged, repaired and newly constructed railway tracks. The experimental methods are hammer testing of the track at different positions, hammer testing of the soil, measurement of train passages, and in all cases, measurements with geophones at different positions. The measured signals are evaluated for wave velocities (dispersion of the soil or the track-soil system), for transfer functions (transfer admittances of the soil, compliances of the track in amplitude and phase), and one-third octave band spectra of the track response to hammer and train excitation. These methods are applied at different stages of the track construction. Before track construction, wave velocities and transfer functions of the sub-soil can indicate problems with soft soils. After track construction, a check of the acceptable state of the track can be done by comparison of many excitation positions and track sites. After a track damage (a lose sleeper or a lose plate of a slab track) and after its repair, the sensitivity of the different measurement quantities to different track errors and the achieved improvement of the repair can be determined. The contribution shows examples of all these track situations.

Offshore wind energy towers are dynamically loaded by waves and wind. Pile foundations provide stiffness and damping and should be properly calculated. A combined finite-element boundary-element method for the dynamic interaction of flexible structures and the soil has been developed. The flexible structures such as single piles or complete wind energy towers are modeled by the finite element method whereas the homogeneous or layered soil is modeled by the boundary element method which uses the Green’s functions for interior loads in the layered half-space to establish the dynamic stiffness matrix of the soil. Soils with a stiffness that is continuously increasing with depth can be modeled as multi-layer soils with step-wise increasing stiffness. The effects of different parameters such as the stiffness of the soil, the axial and bending stiffness of the pile, and the radius of the cylindrical contact area will be analysed for the different components of excitation (vertical, horizontal, rotation and coupling). The results can be determined as specific power laws which are different for the different load cases and for the different soil models (Winkler support, homogeneous continuum, continuum with increasing stiffness). The dynamic effect of radiation damping will be analysed by the frequency-dependent compliance functions. A clear layering of the soil can cause noticeable changes in the dynamic compliances as reductions of the stiffness and the damping in certain frequency ranges (below and around layer resonance frequencies). The distribution of the displacements along the pile help to explain the observed laws. An example of an offshore wind energy tower has been modeled and calculated for wind, wave and weight loads. The resonances of the tower are usually limited by the radiation damping which is strongest for a soft soil.

This contribution presents experimental methods to detect track damage. At BAM (Federal Institute of Material Research and Testing), a measuring car with a measuring system of 72 channels, geophones, mountings, cables, harmonic and impulsive exciters is used for dynamic measurements of the track, the soil and buildings. An instrumented hammer allows force measurements and to evaluate transfer functions of the track, and the soil. Wave measurements are used to identify the soil characteristics. Train passages are measured at the track and for the train induced ground vibrations. In addition to these in situ options, tests of tracks or track elements can be performed in a large laboratory.

Measurements of ground and track vibrations have been performed at a high-speed line in northern Germany. Impacts on the track and the ground, and passages of different trains with different speeds on different tracks have been measured. Transfer functions of the soil are presented and approximated by theoretical soil models. By using these transfer functions, the measured ground vibration between 2 to 64 m distance from the track can be transformed into a load spectrum which can be used for predictions at other sites. The method is compared to the soil-dependent method of an emission spectrum at a certain distance (8 m for example). The influence of train type, speed and track type is discussed on the base of the different emission quantities and the original measurements. The strong influence of the track, ballast track and slab track, is analysed by a theoretical model in wavenumber domain. The response of the track to the passage of the static load is reduced by the stiffness of the slab, the deformation of the track as well as the impulse acting on the soil. Usually, the impulse on the soil should result in a slow quasi-static movement of the soil, slower at further distances. In a heterogeneous soil, however, the impulses from the static loads scatter and keep parts of the higher impulse frequency band. In this case the reduced impulse spectra of the slab track will yield reduced ground vibration in a certain frequency band. Additional (BAM and international) measurements will be used to discuss this and possible other explanations for the different ground vibration differences.