7.2 Ingenieurbau
Filtern
Dokumenttyp
- Zeitschriftenartikel (65) (entfernen)
Schlagworte
- Compressive strength (4)
- Ground vibration (4)
- Train passage (4)
- Hammer impact (3)
- Slab track (3)
- Structural Health Monitoring (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)
- Beton (1)
- Bewertung (1)
- Boundary element (1)
- Box-Behnken (1)
- Bridge monitoring (1)
- Bridge resonance (1)
- Bridge vibration (1)
- Bruchlastwechselzahlen (1)
- Brückensicherheit (1)
- Building and Construction (1)
- Building response (1)
- Cancellation (1)
- Cement-based composites (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)
- 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)
- 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)
- 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)
- Irregular soil (1)
- Jacket support structure (1)
- Jet erosion test (1)
- Jet impingement (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)
- 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)
- 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)
- 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)
- layered soil (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (65)
- 7.2 Ingenieurbau (65)
- 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)
In this article, a partial selection of experiments on enhancing the impact resistance of structural components with non-metallic, textile-reinforced concrete is discussed. The focus is on the experimental investigations in which the impact resistance of thin, textile-reinforced concrete plates is characterized. The article discusses the materials, fabrics and test setup used. For the experimental work, a drop tower from the Otto Mohr Laboratory, which belongs to the Technische Universtät Dresden, was used. Furthermore, the experimental results are presented and evaluated using different methods. Based on the collected data, a suitable approach to determining the perforation velocity of an impactor through the investigated thin, textile-reinforced concrete plates is shown.
The vehicle–track interaction generates forces and consequently vibrations in the environment. The interaction has been analysed by the simultaneous measurements of vehicle, track and ground vibrations during test runs with varied train speeds. The special effects of the passage over a bridge and through a tunnel are studied and compared with the measurements on a conventional ballasted surface line. The maximum amplitudes, narrow band and one-third octave band spectra are presented for the axle-box accelerations and for the track, bridge and ground vibrations. The different frequencies and frequency bands are related to wheel out-of-roundness, track alignment errors, the sleeper passage and the wheelset–track resonance. An axle impulse component has been observed at the track, at the near-field soil and as a scattered version in the far field. Specific results can be found for the bridge track, where clearly speed-dependent bridge resonances occur due to the axle sequence of the train, and for the tunnel track where soft rail pads are responsible for a strong amplification around the wheelset–track resonance. On the other hand, the axle impulses are strongly reduced by the tunnel track, and the scattered axle impulse component is not as relevant as for the surface track. As a consequence, a strong mid-frequency amplitude reduction of the tunnel compared to the surface line has been measured for low and high train speeds by the Federal Institute of Material Research and Testing (BAM) and by other institutes.
The propagation of ground vibrations is theoretically analysed with frequency-wavenumber and simplified methods. Experimental methods are presented which can characterise the site-specific ground vibrations by wave velocities, stiffness and damping. Measurements with hammer and train excitation have been performed at several sites. The one-third octave spectra show the stiffness-dependent amplitudes and the low- and high-frequency filter effects due to the layering and the damping of the soil. Specific train effects, an additional high-frequency filter, the sleeper passage frequency, and an amplified mid-frequency component can be clearly found. The attenuation with distance is analysed in detail where the theoretical exponential and the empirical frequency-dependent power law are considered. Hammer and train excitation show the same site-specific effects which are mainly due to the stronger or weaker damping of the soil. The train attenuation is generally weaker than the hammer attenuation. The attenuation exponent of the power law, which is strongly dependent on the site and the frequency, is reduced for the train vibration by 0.3 to 0.5 in agreement with the theory. Reasons are discussed for the overall power law and for the dominating mid-frequency component.
Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores (less than1 µm), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption.
In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany.
The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. These effects are prominent in the meso-pore range and might significantly alter the effective diffusion coefficient.
Der zukünftige Eurocode 7 wird ausdrücklich die Nutzung zuverlässigkeitsbasierter Methoden in der geotechnischen Planung und Bemessung erlauben. In Deutschland gibt es bisher kaum Erfahrung in der praktischen Anwendung derartiger Verfahren und entsprechend sind die Vorbehalte gegenüber diesen Methoden oft groß. Der neue DGGT-Arbeitskreis (AK) 2.15 „Zuverlässigkeitsbasierte Methoden in der Geotechnik“ hat sich zum Ziel gesetzt, durch praxisorientierte Anleitungen und Empfehlungen sowie begleitende Aus- und Weiterbildungsangebote den praktischen Zugang zu diesen Verfahren zu unterstützen. Ziel ist es, Möglichkeiten und Grenzen zu verdeutlichen sowie vor allem ihre Potenziale zu erschließen. In dem vorliegenden Beitrag werden allgemeine Grundlagen und die zukünftigen Arbeitsfelder des AK 2.15 vorgestellt. Ausgehend von der Einführung relevanter Fachbegriffe wird zunächst die Einbettung zuverlässigkeitsbasierter Verfahren in den aktuellen Normungs- und Regelungskontext aufgezeigt. Anschließend werden anhand des Lebenszyklus eines geotechnischen Bauwerks die Unsicherheiten in den geotechnischen Prognosen und Bewertungen beschrieben. Daran anknüpfend wird aufgezeigt, an welchen Stellen zuverlässigkeitsbasierte Methoden als mögliches Werkzeug sinnvoll genutzt werden können, um Ingenieur:innen, Bauherr:innen und Prüfer:innen in Nachweis- und Entscheidungsprozessen zu unterstützen. Zu den sich daraus ableitenden Arbeitsthemen werden durch den AK 2.15 zukünftig Empfehlungen erarbeitet und sukzessive veröffentlicht
Quenching and partitioning (Q&P) steels are characterized by an excellent combination of strength and ductility, opening up great potentials for advanced lightweight components. The Q&P treatment results in microstructures with a martensitic matrix being responsible for increased strength whereas interstitially enriched metastable retained austenite (RA) contributes to excellent ductility. Herein, a comprehensive experimental characterization of microstructure evolution and austenite stability is carried out on a 42CrSi steel being subjected to different Q&P treatments. The microstructure of both conditions is characterized by scanning electron microscopy as well as X‐ray diffraction (XRD) phase analysis. Besides macroscopic standard tensile tests, RA evolution under tensile loading is investigated by in situ XRD using synchrotron and laboratory methods. As a result of different quenching temperatures, the two conditions considered are characterized by different RA contents and morphologies, resulting in different strain hardening behaviors as well as strength and ductility values under tensile loading. In situ synchrotron measurements show differences in the transformation kinetics being rationalized by the different morphologies of the RA. Eventually, the evolution of the phase specific stresses can be explained by the well‐known Masing model.
The reduction in train-induced ground vibrations by different railway lines and by mitigation measures in the propagation path was analysed in a unified approach by two-dimensional finite element calculations. In general, there was no reduction at low frequencies, and the reduction be-came stronger with increasing frequencies. A maximum reduction of 0.1 at high frequencies was established with an open trench. Reductions between 0.7 and 0.2 have been found for the other sit-uations, filled trenches, walls, plates, and blocks, as well as for railway lines on dams, in cuts and in a tunnel. Bridges can produce amplifications due to their resonance frequencies, but also strong reductions due to massive bridge piers. The influence of some parameters has been analysed, such as the bridge span, the inclination of the dam and the cut, the stiffness of the soil, and the tunnel structure. The dynamic track stiffnesses of a surface, bridge, and tunnel track have been calculated using the 3D finite-element boundary-element method for comparison with corresponding meas-urements.
Brücken müssen laufend überwacht werden, damit die Unsicherheiten hinsichtlich ihres Zustands, ihrer Beanspruchung und ihrer Leistungsfähigkeit verringert werden können. Diese Aufgabe soll künftig mit digitalen Methoden erleichtert werden. Im folgenden Beitrag werden deshalb die digitale Bauwerksmodellierung und die Entscheidungsfindung beleuchtet. Dazu wird gezeigt, wie Zustandsdiagnosen und -prognosen digital ermöglicht werden und wie durch diagnostische und prognostische Modelle eine wissenschaftliche Basis für risikobasierte Entscheidungen über Erhaltungsmaßnahmen und für den Übergang vom reaktiven zum vorausschauenden Brückenmanagement gebildet werden kann. Dabei wird klar: Jede Brücken-Überwachung bedarf einer Gesamtmethodik, ihre wichtigsten Elemente sind: Datenerfassung, Datenmanagement, Datenanalyse, Bauwerksmodellierung, Bauwerksbewertung und die letztendlichen Entscheidungen über notwendige Erhaltungsmaßnahmen.
Using digital twins for decision making is a very promising concept which combines simulation models with corresponding experimental sensor data in order to support maintenance decisions or to investigate the reliability. The quality of the prognosis strongly depends on both the data quality and the quality of the digital twin. The latter comprises both the modeling assumptions as well as the correct parameters of these models. This article discusses the challenges when applying this concept to realmeasurement data for a demonstrator bridge in the lab, including the data management, the iterative development of the simulation model as well as the identification/updating procedure using Bayesian inference with a potentially large number of parameters. The investigated scenarios include both the iterative identification of the structural model parameters as well as scenarios related to a damage identification. In addition, the article aims at providing all models and data in a reproducibleway such that other researcher can use this setup to validate their methodologies.
Messtechnische Systeme zur Dauerüberwachung von Bauwerken ermöglichen Einblicke in deren reale Trag- und Verformungsverhalten. Die Planung und technische Umsetzung solcher Maßnahmen erfordern für die erfolgreiche Erfüllung der Aufgabenstellungen eine hohe Fachkompetenz, sowohl auf der planerischen Seite, als auch für die fachliche Bewertung von angebotenen Monitoringlösungen. Als Hilfestellung dafür wurde von der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) das Merkblatt „Dauerüberwachung von Ingenieurbauwerken“ erarbeitet, welches nun verfügbar ist. In diesem Beitrag werden die Inhalte des neuen Merkblatts vorgestellt und dieses in die vorhandene Literatur eingeordnet.