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- Englisch (26) (entfernen)
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- Slab track (6)
- Field tests (5)
- Hammer impact (5)
- Ground vibration (4)
- Railway track (4)
- Track damage (4)
- Track-soil interaction (4)
- Train passage (4)
- Vibration measurements (3)
- Amplitude-distance laws (2)
- Ballast track (2)
- Boundary element method (2)
- Displacements (2)
- Dynamic testing (2)
- Environmental vibrations (2)
- Finite element method (2)
- Hammer tests (2)
- Measurement (2)
- Mitigation (2)
- Soil properties (2)
- Track vibration (2)
- Train passages (2)
- Achsfolgespektren (1)
- Amplitude-charge weight laws (1)
- Assessment (1)
- Axle box measurements (1)
- Bauteile (1)
- Bauwerke (1)
- Brücken (1)
- Building vibration (1)
- Compliance function (1)
- Damping (1)
- Dispersion (1)
- Evaluation (1)
- Explosion-induced ground vibrations (1)
- Laboratory tests (1)
- MASW (1)
- Material damping (1)
- Modalanalyse (1)
- Modes (1)
- Monitoring (1)
- Prediction of explosion induced ground and building vibration (1)
- Railway measurement campaign (1)
- Rayleigh wave (1)
- SASW (1)
- SPAC (1)
- Scattering damping (1)
- Switch (1)
- Track damage monitoring (1)
- Track deflection (1)
- Turnout (1)
- Under sleeper pads (1)
- Vehicle-track interaction (1)
- Vibration excitation (1)
- Wave attenuation (1)
- Wave theory of attenuation (1)
- Wave velocity (1)
- Waves (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (9)
- 7.2 Ingenieurbau (9)
Eingeladener Vortrag
- nein (2)
The damage detection and repair control have become important tasks for ballast and slab tracks. Measurements which compare the damaged and the repaired status of the same track section at different times, or which compare a damaged and an intact track section at the same time, have been successfully performed at some sites in Germany. The loss of contact between the sleeper and the track plate, between the track plate and the base plate, and between the base plate and the base layer have been analysed. The soil properties of each site have been measured and have been used to establish realistic track-soil models. Theoretical results of the wavenumber domain and the finite-element boundary element method have been compared with the experimental results. The observed experimental and theoretical results, changes in the time histories of displacements and velocities due to train passages and in the transfer functions (receptances) due to hammer impacts, are encouraging that these measurements can be used to detect track damage.
There is a strong need for cost-effective mitigation measures for
turnouts. SBB has initiated a series of examinations using different methodologies to gain a deeper understanding of the excitation mechanisms at low frequencies, in addition to that obtained in the RIVAS project. To date it is not yet clear what constitutes a complete measurement data set that would enable understanding most of the vibration excitation mechanisms in turnouts. Increasing vibration at turnouts in comparison to normal track is observed for all measured frequencies.
The different methodologies are presented in the paper. Under-sleeper pads (USP) are a cost-effective method to reduce vibration at frequencies above 63 Hz (1/3 octave), but there is probably no improvement for frequencies below 63 Hz. A first test of new frog geometry did not show relevant improvements in Vibration emission in comparison to a reference frog geometry. Axle box acceleration measurements are an interesting method to identify defects in a turnout. A specialized measurement system of rail roughness could identify certain geometry Problem areas for some frogs. Noise increases also are observed at turnouts for frequencies ranging between 80 to 1000 Hz. The use of railway source models to calculate
contact forces for ballasted track and turnouts seems promising, in particular for understanding the influence of ground.
The damage detection and repair control have become important tasks for ballast and slab tracks. Measurements which compare the damaged and the repaired status of the same track section at different times, or which compare a damaged and an intact track section at the same time, have been successfully performed at some sites in Germany with slab tracks and ballast tracks and compared with the theoretical behaviour of intact and damaged tracks. The loss of contact between the sleeper and the plate, between the plate and the base layer, and some problems with soft or weakened soil have been analysed. The observed results, changes in the time histories of displacements and velocities due to train passages and in the transfer functions (compliances) due to hammer impacts, are encouraging that these measurements can be used to detect track damage. In addition, calculations with the combined finite-element boundary-element method have been used to confirm the conclusions about intact or damaged railway tracks.
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.