7.2 Ingenieurbau
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- Zeitschriftenartikel (68) (entfernen)
Schlagworte
- Compressive strength (4)
- Ground vibration (4)
- Structural Health Monitoring (4)
- Train passage (4)
- Hammer impact (3)
- Slab track (3)
- Train-induced ground vibration (3)
- Axle sequence (2)
- Bauwerksüberwachung (2)
- Bridge (2)
- Brücken (2)
- Damage characterization (2)
- Damage detection (2)
- Earth block masonry (2)
- Fatigue (2)
- Fly ash (2)
- Impact (2)
- Layered soil (2)
- Luminescence (2)
- Metakaolin (2)
- Mitigation (2)
- Model updating (2)
- Moisture content (2)
- Offshore (2)
- Planar tomography (2)
- Reinforced concrete structure (2)
- Relative humidity (2)
- Resonance (2)
- SHM (2)
- Soil erosion (2)
- Static axle loads (2)
- Structural health monitoring (2)
- System identification (2)
- Track-soil interaction (2)
- Vehicle–track interaction (2)
- Verkehrsinfrastukturen (2)
- Wind turbine tower (2)
- Acceleration sensors (1)
- Acoustic emission (1)
- Acoustic emission analysis (1)
- Ambient excitation (1)
- Ansys Autodyn (1)
- Asymptotic local approach (1)
- Attenuation (1)
- Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases (1)
- Automated operational modal analysis (1)
- Automatic modal parameters identification (1)
- Axle impulses (1)
- BIM (1)
- Ballast track (1)
- Bauwerksdiagnostik (1)
- Bauwerksmonitoring (1)
- Bayesian analysis (1)
- Belastungstest (1)
- Bemessung (1)
- Benchmark (1)
- Beschleunigungssensoren (1)
- Beton (1)
- Bewertung (1)
- Boundary element (1)
- Box-Behnken (1)
- Bridge monitoring (1)
- Bridge resonance (1)
- Bridge vibration (1)
- Bruchlastwechselzahlen (1)
- Brückensicherheit (1)
- Building Information Modeling (1)
- Building and Construction (1)
- Building response (1)
- Cancellation (1)
- Cement-based composites (1)
- Cemented soil (1)
- Chemisorption (1)
- Civil and Structural Engineering (1)
- Coating (1)
- Cohesive granular materials (1)
- Combined finite-element boundary-element method (1)
- Compliance function (1)
- Components of excitation (1)
- Compression tests (1)
- Computational (1)
- Concrete (1)
- Condensed Matter Physics (1)
- Continuous soil (1)
- Continuously inhomogeneous geological media (1)
- Continuously inhomogeneous soils (1)
- Crack (1)
- Crack damage detection (1)
- Cracks (1)
- DUCON® (1)
- Damage Identification (1)
- Damage evolution (1)
- Damage localization (1)
- Datenmanagement (1)
- Decision matrix analysis (1)
- Detection (1)
- Deterioration (1)
- Digitale Zwillinge (1)
- Digitalisierung (1)
- Discrete Element Method (1)
- Discrete element method (1)
- Drucker-Prager (1)
- Druckschwellenversuch (1)
- Ductility (1)
- Dynamic axle loads (1)
- Dynamic excitation (1)
- Dynamic loads (1)
- E-modulus (1)
- Earth blocks (1)
- Earth masonry (1)
- Earth material (1)
- Environmental and Operational Variability (1)
- Environmental influence (1)
- Erhaltungsmanagement (1)
- Ermüdung (1)
- Ermüdungsverhalten (1)
- Erosion (1)
- Estimation (1)
- Excitation forces (1)
- FEM analysis (1)
- Fatigue damage (1)
- Fatigue strength (1)
- Features (1)
- Fequency domain (1)
- Fibre optic sensors (1)
- Filter effects (1)
- Finite element (1)
- Finite element analysis (1)
- Finite element method (1)
- Finite elements (1)
- Finite-element boundary-element method (1)
- Flexible car body (1)
- Flexible wheelset (1)
- Fluid Dynamics (1)
- Fluidized beds (1)
- GPA (1)
- GPU Parallel computing (1)
- General Materials Science (1)
- Geology (1)
- Geometric vehicle and track irregularities (1)
- Global ambient vibrations (1)
- Granular cohesion (1)
- Granular materials (1)
- Grout (1)
- Grouted connection (1)
- Grouting (1)
- High-rise building (1)
- Horizontal wind turbine (1)
- Hydraulic jet erosion (1)
- IEPE (1)
- Impact loading (1)
- Imperfektion (1)
- Impinging jet (1)
- Inclination angle (1)
- Inspection (1)
- Instandhaltung (1)
- Irregular soil (1)
- Jacket support structure (1)
- Jet erosion test (1)
- Jet impingement (1)
- Kalibrierung (1)
- LBM-DEM (1)
- Laminar flow (1)
- Large components (1)
- Lateral dynamic displacement (1)
- Lattice Boltzmann Method (1)
- Lattice Boltzmann method (1)
- Layered soils (1)
- Load identification (1)
- Load tests (1)
- Load vector (1)
- Load-bearing behaviour (1)
- Local approaches (1)
- Long-term shrinkage (1)
- Low-frequency shaker (1)
- MEMS (1)
- Maschinenfundament (1)
- Material moisture (1)
- Measurement campaigns (1)
- Merkblatt (1)
- Messen im Bauwesen (1)
- Micro silica (1)
- Micro-reinforcement (1)
- Micromechanical modelling (1)
- Microsilica (1)
- Mix design (1)
- Mobile elements (1)
- Modal analysis (1)
- Model Building (1)
- Model Updating (1)
- Model update (1)
- Modell-Update (1)
- Modulus of elasticity (1)
- Moisture (1)
- Monitoring (1)
- Monitoring-informed inspection and maintenance planning (1)
- Multi-beam track model (1)
- Nelson’s method (1)
- Numeric simulation (1)
- Numerical modeling (1)
- Numerische Analysen (1)
- Obstacles (1)
- Offshore Wind (1)
- Offshore geomechanics (1)
- Offshore wind turbine (1)
- Offshore-Windenergie (1)
- Operational modal analysis (1)
- Optimal sensor placement (1)
- Perfectly Matched Layer (PML) (1)
- Physisoprtion (1)
- Piaui state (1)
- Pile bending stiffness (1)
- Pile foundation (1)
- Post-impact evaluation (1)
- Pressure (1)
- Probability of detection (1)
- Probekörpergeometrien (1)
- Prädiktive Instandhaltung (1)
- Quasi-static and dynamic tests (1)
- Quasi-static response; (1)
- Rail roughness (1)
- Railway bridge (1)
- Railway induced vibration (1)
- Railway track (1)
- Random dynamics and vibrations (1)
- Random stiffness variation (1)
- Randomly heterogeneous soil (1)
- Recovery experiments (1)
- Referenzbeispiel (1)
- Referenzkennzeichnungssystem (1)
- Rehabilitation (1)
- Reliability (1)
- Remote sensing vibrometer (1)
- Repair (1)
- Richtlinie (1)
- Rigid vehicle model (1)
- SHCC (1)
- Sandstone (1)
- Santa-marta (1)
- Scattered axle impulses (1)
- Scattering (1)
- Schrauben (1)
- Sensitivity vectors (1)
- Serra da cangalha (1)
- Shell buckling (1)
- Sicherheit (1)
- Soil forces (1)
- Soil properties (1)
- Soil stiffness (1)
- Sorption isotherm (1)
- Static loading (1)
- Statistical evaluation (1)
- Statistical pattern recognition (1)
- Statistical tests (1)
- Stereo photogrammetry (1)
- Stiffness variation (1)
- Strain (1)
- Strength (1)
- Stress stiffening (1)
- Stress-strain relation (1)
- Stress–strain-relation (1)
- Structural system identification (1)
- Structural systems (1)
- Strukturmonitoring (1)
- Sustainable binders (1)
- TRC (1)
- Tagung (1)
- Temperature effect (1)
- Temperature effect rejection (1)
- Temperature modeling (1)
- Track and vehicle irregularities (1)
- Track damage monitoring (1)
- Track damage quantification (1)
- Track deflection (1)
- Track displacements (1)
- Track filter (1)
- Track filtering (1)
- Train-induced vibration (1)
- Transverse butt weld (1)
- Trench (1)
- Tunnel (1)
- Tunnel-to-surface reduction (1)
- UAS (1)
- UHPC (1)
- Ultrasonic testing (1)
- Umwelteinflüsse (1)
- Unbounded domain (1)
- Uncertainty quantification (1)
- Under-sleeper pads (1)
- Value of information (1)
- Variational Bayesian statistics (1)
- Vehicle-track interaction (1)
- Vehicle-track-soil interaction (1)
- Vibration analysis (1)
- Vibration measurement (1)
- Viscosity (1)
- Vorspannung (1)
- Wahrscheinlichkeit (1)
- Water Science and Technology (1)
- Wave propagation (1)
- Wavenumber domain (1)
- Wavenumber integrals (1)
- Weld imperfections (1)
- Wellenausbreitung (1)
- Wheelset (1)
- Wheelset accelerations (1)
- Wind energy (1)
- Wind energy tower (1)
- Windenergieanlage (1)
- Windenergieanlagen (1)
- Workability (1)
- Zuverlässigkeit (1)
- acceleration sensors (1)
- calibration (1)
- environmental influences (1)
- layered soil (1)
- transmission behavior (1)
- Übertragungsverhalten (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (68)
- 7.2 Ingenieurbau (68)
- 8 Zerstörungsfreie Prüfung (6)
- 7.4 Baustofftechnologie (4)
- 7.0 Abteilungsleitung und andere (2)
- 7.1 Baustoffe (2)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (2)
- 7.7 Modellierung und Simulation (1)
- 8.0 Abteilungsleitung und andere (1)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (1)
Paper des Monats
- ja (5)
Die Infrastruktursysteme der Industriestaaten erfordern heute und in Zukunft ein effizientes Management bei alternder Bausubstanz, steigenden Lasten und gleichbleibend hohem Sicherheitsniveau. Digitale Technologien bieten ein großes Potenzial zur Bewältigung der aktuellen und künftigen Herausforderungen im Infrastrukturmanagement. Im BMBF-geförderten Projekt Bewertung alternder Infrastrukturbauwerke mit digitalen Technologien (AISTEC) wird untersucht, wie unterschiedliche Technologien und deren Verknüpfung gewinnbringend eingesetzt werden können. Am Beispiel der Maintalbrücke Gemünden werden ein sensorbasiertes Bauwerksmonitoring, bildbasierte Inspektion mit durch Kameras ausgestatteten Drohnen (UAS) und die Verknüpfung digitaler Bauwerksmodelle umgesetzt. Die aufgenommenen Bilder dienen u. a. als Grundlage für spätere visuelle Anomaliedetektionen und eine 3D-Rekonstruktion, welche wiederum für die Kalibrierung und Aktualisierung digitaler Tragwerksmodelle genutzt werden. Kontinuierlich erfasste Sensordaten werden ebenfalls zur Kalibrierung und Aktualisierung der Tragwerksmodelle herangezogen. Diese Modelle werden als Grundlage für Anomaliedetektionen und perspektivisch zur Umsetzung von Konzepten der prädiktiven Instandhaltung verwendet. Belastungsfahrten und historische Daten dienen in diesem Beitrag der Validierung von kalibrierten Tragwerksmodellen.
Train-induced ground vibrations are all generated by the vehicle, by static or dynamic vehicle loads. The most important and most accepted excitation are the dynamic wheel loads from the passage over track irregularities. Dynamic wheel loads will be compared from parallel axle-box and ground vibration measurements at more than seven sites. Some low-frequency excitation of ground vibrations, typically between 10 and 30 Hz, cannot be found in the axle-box measurements. Therefore, other vehicle modes, such as rigid bogie modes, flexible carriage modes, rigid and flexible wheelset modes, have been analysed for additional excitation forces. These vehicle dynamics analyses give an explanation for higher axle-box results at high frequencies, but not for the excitation of the higher low-frequency ground-vibration component. Finally, the effect of the moving static train loads will be analysed. For a regular track and soil, the moving static train loads yield the quasi-static response which exists only in the low-frequency nearfield of the track. If the support stiffness is randomly varying along the track, the pulses on the track generate an additional low-frequency component which is called the irregular pulse responses.
This component will be demonstrated by numerical analysis where all axle pulses are superposed in frequency domain.
The Perfectly Matched Layer (PML) method is an efficient approach to imposing radiation conditions at the bounded region of interest in case of wave propagation in unbounded domains. This paper presents and validates 3D FE/PML numerical schemes based on two different PML formulations for homogeneous and inhomogeneous geological media exhibiting discrete or continuous inhomogeneity. In the equation of motion for the PML domain the applied stretching behavior is expressed either as complex material properties or as complex coordinates. Both PML formulations are implemented in the FEM and verified against analytical solutions. Three different types of material inhomogeneity are considered: layered half-space, continuously inhomogeneous half-space with linear velocity profile and continuously inhomogeneous half-space with nonlinear velocity profile. Sensitivity analyses are conducted, and the performance of the developed numerical schemes is investigated taking into account a broad variation of the PML parameters. Recommendations are given for the optimal values of the PML parameters for the case of homogeneous and inhomogeneous geological media.
Aim of this study is to provide information about moisture dependent material behaviour of unstabilised loadbearing earth blocks and mortars. Compressive strength and Young’s modulus were investigated after conditioning in varying relative humidity reaching from 40 % up to 95 %. The material composition and physical properties were investigated to understand the influence of relative humidity onto the mechanical properties. A normalisation of strength and stiffness by the values obtained at 23 ◦C and 50 % relative humidity reveals a linear dependence of compressive strength and Young’s modulus that is regardless of the material composition.
Thus, it is possible to describe the influence of relative humidity onto the load-bearing behaviour of unstabilised earth masonry materials in a generally valid formulation.
Die moderne Gesellschaft in Deutschland und Europa profitiert von der hervorragenden baulichen Infrastruktur, die für uns viele Aspekte aus den Bereichen Mobilität, Energieversorgung, Transport, Umweltschutz, (Nah-)Erholung und Gefahrenabwehr zur Alltäglichkeit werden lassen und uns ein hohes Gefühl der technischen Sicherheit vermitteln. Viele der Annehmlichkeiten, wie beispielweise ein Hochgeschwindigkeitseisenbahnverkehrsnetz, zuverlässige Stromversorgung im europäischen Verbundsystem und ein immenser Personen-, Güter- und Warenverkehr auf der Straße, zu Wasser und in der Luft ist ohne eine leistungsfähige, resiliente und zuverlässige bauliche Infrastruktur undenkbar.
Irregularities of the track are a main cause of train-induced ground vibration, and track maintenance is of great importance. Although geometric irregularities at the wheel-rail contact are widely used, other types of irregularities, such as stiffness irregularities, irregularities from different track positions and irregularities in the wave propagation, were analysed in the present study. The track behaviour was investigated by a multi-beam-on-soil model. This track model is coupled with a vehicle model to calculate the vehicle–track interaction. The track model was also used for the track filtering, which transfers a track support error to the equivalent rail irregularity or, conversely, the sharp axle pulse on the rail to a smoother pulse on the soil. In the case in which this filtering varies randomly along the track, the pulses of the moving static load induce a certain ground Vibration component (“the scatter of axle pulses”). This effect was calculated by the superposition of axle pulses in the frequency domain and by a stochastic simulation. Simultaneous vehicle, track and soil measurements at a certain site were used to evaluate the different excitation and ground Vibration components. The agreement between calculations and axle-box and soil measurements is good. The ground vibrations calculated from rail irregularities and corresponding dynamic loads, however, clearly underestimate the measured ground vibration amplitudes. Only the static load that is moving over a varying track support stiffness can produce the important mid-frequency ground Vibration component by the scatter of axle pulses.
The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.
In this article, the passage of different trains over different bridges will be studied for resonant excitation. The intensity of the resonance will be estimated in frequency domain by using three separated spectra. At first, the excitation spectrum of the modal forces is built by the mode shape and the passage time of the train over the bridge. The second spectrum is the frequency response function of the bridge which include the modal frequency, damping and mass. The third part is the spectrum of the axle sequence of the train. The influences of train speed, bridge length, bridge support, track irregularities, and train type on the resonance amplitudes will be analysed for each of these spectra separately for getting a better insight. A variety of axle-sequence spectra and corresponding rules will be presented for different vehicles and trains. As examples, the passage of a slow freight train over a long-span bridge, a normal passenger train over a medium-span bridge, and a high-speed train over a short bridge will be analysed. Corresponding measurements show the amplification, but also the cancellation of the subsequent axle responses. Namely in one of the measurement examples, the first mode of the bridge was amplified and the second mode was cancelled at a low speed of the train and vice versa at a higher speed.
The statistical subspace-based damage detection technique has shown promising theoretical and practical results for vibration-based structural health monitoring. It evaluates a subspacebased residual function with efficient hypothesis testing tools, and has the ability of detecting small changes in chosen system parameters. In the residual function, a Hankel matrix of Output covariances estimated from test data is confronted to its left null space associated to a reference model. The hypothesis test takes into account the covariance of the residual for decision making. Ideally, the reference model is assumed to be perfectly known without any uncertainty, which is not a realistic assumption. In practice, the left null space is usually estimated from a reference data set to avoid model errors in the residual computation. Then, the associated uncertainties may be non-negligible, in particular when the available reference data is of limited length. In this paper, it is investigated how the statistical distribution of the residual is affected when the reference null space is estimated. The asymptotic residual distribution is derived, where its refined covariance term considers also the uncertainty related to the reference null space estimate. The associated damage detection test closes a theoretical gap for real-world applications and leads to increased robustness of the method in practice. The importance of including the estimation uncertainty of the reference null space is shown in a numerical study
and on experimental data of a progressively damaged steel frame.
The dynamic behaviour of slab and ballast tracks has been investigated by measurements and calculations. Hammer impacts and train passages have been analysed. Measurements have been performed by geophones (velocity transducers) which have been time-integrated to displacements. The calculations are done in frequency-wavenumber domain for multi-beam-on-continuous soil models. The characteristics of the different tracks and track elements have been established in theory and experiment. The frequency-dependent compliances (displacement transfer functions) show clear rail-on-rail-pad resonances or highly damped track-soil resonances. Compared to the rail and sleeper, the track plate has much lower amplitudes. The slab track has usually the highest rail amplitudes due to soft rail pads. The train passage yields track displacements which are a superposition of the axle loads from the two neighbouring axles of a bogie and from the two bogies of two neighbouring carriages. This global behaviour is characteristic for the track plate of the slab track whereas the rails of the slab and the ballast track behave more local with only one bogie of influence. The measurements agree very well with the theory of the continuous soil in case of the six measured slab tracks and acceptably well for the six measured ballast tracks. The measurements allow to find appropriate model parameters and to check the models, for example the Winkler model of the soil has been found less appropriate as it reacts more locally.