7.2 Ingenieurbau
Filtern
Erscheinungsjahr
- 2019 (56) (entfernen)
Dokumenttyp
- Vortrag (33)
- Beitrag zu einem Tagungsband (18)
- Zeitschriftenartikel (3)
- Buchkapitel (1)
- Posterpräsentation (1)
Referierte Publikation
- nein (56) (entfernen)
Schlagworte
- Fatigue (5)
- Train-induced ground vibration (5)
- Damage characterization (4)
- Ground vibration (4)
- Grout (4)
- Impact (4)
- Numeric simulation (4)
- Planar tomography (4)
- Reinforced concrete structure (4)
- Temperature rejection (4)
- Vehicle-track-soil interaction (4)
- Damage localization (3)
- Layered soils (3)
- Offshore foundations (3)
- Soil-structure interaction (3)
- Vibration measurements (3)
- Wellengeschwindigkeit (3)
- Bahnerschütterungen (2)
- Bodenübertragungsfunktion (2)
- Bridges (2)
- Cable failure (2)
- Cable-stayed bridge (2)
- Compaction Grouting (2)
- Compressive Cyclic loading (2)
- Crack detection (2)
- Crack formation (2)
- Crack pattern (2)
- Cyclic load (2)
- Dispersionsmessung (2)
- Displacements (2)
- Drone (2)
- Excitation forces (2)
- Fly ash (2)
- Grouted connection (2)
- Hammer impact (2)
- High-strength concrete (2)
- Injection Sequence (2)
- Load vector (2)
- Long-term shrinkage (2)
- Metakaolin (2)
- Micro silica (2)
- Mitigation (2)
- Modal Analysis (2)
- Model interpolation (2)
- Non destructive testing (2)
- Offshore Pile Foundation (2)
- Offshore wind turbines (2)
- SDDLV (2)
- SHM (2)
- Slab track (2)
- Static load (2)
- Statistical evaluation (2)
- Statistical method (2)
- Steel structures (2)
- Structural Health Monitoring (2)
- Structural health monitoring (2)
- Subspace-based method (2)
- Tensile Capacity (2)
- Train excitation (2)
- Train passage (2)
- Train speed (2)
- Ultrasonic testing (2)
- Vibration (2)
- Wind Turbines (2)
- Zuggeschwindigkeit (2)
- Analytical Design Methods (1)
- BIM (1)
- Brücken (1)
- Climate Chamber (1)
- Components of excitation (1)
- Concrete (1)
- Deckeneigenfrequenzen (1)
- Design methods (1)
- EERA Joint Program (1)
- Earthen hydraulic infrastructures (1)
- Environmental Effects (1)
- Erneuerbare Energien (1)
- Erosion (1)
- Foundation Pile (1)
- GPU parallel computation (1)
- Gebäudemodelle (1)
- Gebäudeschwingungen (1)
- Ground vibration measurements (1)
- Horizontal stress (1)
- Inhomogeneous soils (1)
- Inspection planning (1)
- Interface (1)
- Klimakammer (1)
- Measurement campaigns (1)
- Mechanical challenges (1)
- Messen im Bauwesen (1)
- Micromechanical analysis (1)
- Micromechanical modelling (1)
- Multi-beam method (1)
- Numerical modelling (1)
- Offshore (1)
- Offshore geotechnics (1)
- Offshore wind energy (1)
- Offshore wind energy foundations (1)
- Physical phenomenology (1)
- Physical testing (1)
- Pile foundations (1)
- Prediction (1)
- Reliability (1)
- Risk (1)
- SHM Environmental (1)
- Scattered axle impulses (1)
- Soft track elements (1)
- Soil-water-structure interaction (1)
- Spektralanalyse (1)
- Stability Buckling soil-structure-interaction piles offshore (1)
- Tagung (1)
- Temperature effects (1)
- Temperatureinflüsse (1)
- Track beam (1)
- Un- certainty (1)
- Uncertainty (1)
- Vehicle-track interaction (1)
- Wavenumber integrals (1)
- Wavenumber method (1)
- Wellenausbreitung (1)
- Wheelset accelerations (1)
- Wind energy (1)
- Windenergie (1)
- elastische Gebäudelagerungen (1)
- risk, reliability, inspection planning, offshore wind turbines (1)
Organisationseinheit der BAM
- 7.2 Ingenieurbau (56) (entfernen)
Eingeladener Vortrag
- nein (33)
Temperature variation can be a nuisance that perturbs vibration based structural health monitoring (SHM) approaches for civil engineering structures. In this paper, temperature affected vibration data is evaluated within a stochastic damage detection framework, which relies on a null space based residual. Besides two existing temperature rejection approaches – building a reference state from an averaging method or a piecewise method – a new approach is proposed, using model interpolation. In this approach, a General reference model is obtained from data in the reference state at several known reference temperatures.
Then, for a particular tested temperature, a local reference model is derived from the general reference model. Thus, a well fitting reference null space for the formulation of a residual is available when new data is tested for damage detection at an arbitrary temperature. Particular attention is paid to the computation of the residual covariance, taking into account the uncertainty related to the null space Matrix estimate. This improves the test performance, contrary to prior methods, for local and global damages, resulting in a higher probability of detection (PoD) for the new interpolation approach compared to previous approaches.
Subspace-based damage detection handling temperature effects and uncertainty in the reference
(2019)
Temperature variation can be a nuisance that perturbs vibration based structural health monitoring (SHM)approaches for civil engineering structures. In this paper, temperature affected vibration data is evaluated within a stochastic damage detection framework, which relies on a null space based residual. Besides two existing temperature rejection approaches – building a reference state from an averaging method or a piecewise method – a new approach is proposed, using model interpolation. In this approach, a general reference model is obtained from data in the reference state at several known reference temperatures. Then, for a particular tested temperature, a local reference model is derived from the general reference model. Thus, a well fitting reference null space for the formulation of a residual is available when new data is tested for damage detection at an arbitrary temperature. Particular attention is paid to the computation of the residual covariance, taking into account the uncertainty related to the null space matrix estimate. This improves the test performance, contrary to prior methods, for local and global damages, resulting in a higher probability of detection (PoD) for the new interpolation approach compared to previous approaches.
At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety.
Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge.
For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required.
This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures.
At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety.
Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge.
For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required.
This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures.
Fatigue in Concrete
(2019)
The current knowledge about fatigue behavior of concrete is still incomplete. This concerns especially the progress of fatigue which precedes the fatigue failure. An overview on the fatigue behaviour in concrete is given. Therefore, the process of fatigue itself under cyclic compressive loading was investigated in a systematic and comprehensive way. The aim of this investigation was to obtain a deeper insight and to provide a better understanding of the damage process occurring within the material during fatigue loading.
Kontinuierliche Sensorbasierte Bauwerksmessungen leisten einen wichtigen Beitrag zur Sicherheit von Verkehrsbauwerken. Hierzu werden im Vorhaben AISTEC Referenzbauwerke und Referenzverfahren untersucht mit Schwerpunkt auf den Einfluss klimatischer Bedingungen. Der Vortrag stellt den aktuellen Projektstand des FB 7.2 vor.
Grouts have numerous applications in construction industry such as joint sealing, structural repair, and connections in precast elements. They are particularly favoured in rehabilitation of structures due to penetrability and convenience of application. Grouts for repair applications typically require high-performance properties such as rapid strength development and superior shrinkage characteristics. Sometimes industrial by-products referred as supplementary cementitious materials (SCM) are used with neat cement due to their capabilities to provide binding properties at delayed stage. Micro silica, fly ash and metakaolin are such SCMs, those can modify and improve properties of cement products. This study aims at investigating long-term mass loss and linear shrinkage along with long-term compressive and flexural strength for grouts produced from ultrafine cement and SCMs. A series of mixtures were formulated to observe the effect of SCMs on these grout properties. Properties were determined after 365 days of curing at 23oC and 55% relative humidity. The effect of SCMs on the properties are characterised by statistical models. Response surfaces were constructed to quantify these properties in relation to SCMs replacement. The results suggested that shrinkage was reduced by metakaolin, while micro silica and fly ash had positive effects on compressive and flexural strength, respectively.
Owners or operators of offshore wind farms perform inspections to collect information on the condition of the wind turbine support structures and perform repairs if required. These activities are costly and should be optimized. Risk-based methods can be applied to identify inspection and repair strategies that ensure an optimal balance between the expected total service life cost of inspection and repair, and the achieved risk reduction. Such an optimization requires explicit modeling of repairs. In this paper, the impact of different repair models on the results of a risk-based optimization of inspection and repair strategies is quantified in a numerical example considering a jacket-type steel frame subject to high-cycle fatigue. The example showed that, in this specific application, there is no need for detailed modeling of the behavior of repaired welded connections.
Owners or operators of offshore wind farms perform inspections to collect information on the condition of the wind turbine support structures and perform repairs if required. These activities are costly and should be optimized. Risk-based methods can be applied to identify inspection and repair strategies that ensure an optimal balance between the expected total service life cost of inspection and repair, and the achieved risk reduction. Such an optimization requires explicit modeling of repairs. In this paper, the impact of different repair models on the results of a risk-based optimization of inspection and repair strategies is quantified in a numerical example considering a jacket-type steel frame subject to high-cycle fatigue. The example showed that, in this specific application, there is no need for detailed modeling of the behavior of repaired welded connections.