7.2 Ingenieurbau
Filtern
Dokumenttyp
- Vortrag (169)
Referierte Publikation
- nein (169)
Schlagworte
- Structural Health Monitoring (16)
- Offshore wind energy (9)
- Ground vibration (8)
- Brücken (7)
- Fatigue (7)
- Offshore (7)
- Design methods (6)
- Physical phenomenology (6)
- Pile foundations (6)
- Structural health monitoring (6)
- Offshore wind turbines (5)
- SHM (5)
- Bahnerschütterungen (4)
- Building vibration (4)
- Deterioration (4)
- Foundations (4)
- Gründungsstrukturen (4)
- Model interpolation (4)
- Monitoring (4)
- Numerical modelling (4)
- Structural systems (4)
- Windenergie (4)
- Buckling (3)
- Damage characterization (3)
- Datenmanagement (3)
- Deep foundations (3)
- Erschütterungsminderung (3)
- Grout (3)
- Hammer impact (3)
- Impact (3)
- Inspection (3)
- Leichtbau (3)
- Maintenance (3)
- Monopiles (3)
- Offshore Windenergieanlagen (3)
- Offshore geomechanics (3)
- Physical testing (3)
- Planar tomography (3)
- Probabilistic (3)
- Shell Buckling (3)
- Slab track (3)
- Soil-structure interaction (3)
- Steel structures (3)
- Train passage (3)
- Vibration (3)
- Wind Energy (3)
- Zivile Sicherheit (3)
- AISTEC (2)
- Automatisierte schweißtechnische Fertigung (2)
- Bayesian updating (2)
- Belastungsversuch (2)
- Bridges (2)
- Compaction Grouting (2)
- Container loading (2)
- Coupled fluid-particle simulation (2)
- Crack detection (2)
- Damage detection (2)
- Design (2)
- Dispersionsmessung (2)
- Drop test (2)
- Elastische Elemente (2)
- Elastische Gleiselemente (2)
- Emission (2)
- Environmental effects (2)
- Erosion (2)
- Erschütterungen (2)
- Erschütterungsprognose (2)
- Fault detection (2)
- Foundation load (2)
- GPU parallel computation (2)
- Großer Fallturm Horstwalde (2)
- High-performance computing (2)
- High-strength concrete (2)
- Inspection planning (2)
- Klimakammer (2)
- Layered soil (2)
- Micromechanical modelling (2)
- Modalanalyse (2)
- Numeric simulation (2)
- Offshore Pile Foundation (2)
- Offshore foundations (2)
- Offshore geotechnics (2)
- Offshore wind (2)
- Offshore wind turbine (2)
- Pile Tip Buckling (2)
- Railway (2)
- Railways (2)
- Reinforced concrete structure (2)
- Reliability (2)
- Repair (2)
- Repowering (2)
- Risslumineszenz (2)
- Schwingungsdynamik (2)
- Statistical method (2)
- Subspace-based method (2)
- Suction bucket (2)
- Temperature effects (2)
- Temperature rejection (2)
- Train-induced ground vibration (2)
- Tunnel (2)
- Ultrasonic testing (2)
- Vehicle-track-soil interaction (2)
- Vibration measurement (2)
- Vibration measurements (2)
- Wellengeschwindigkeit (2)
- Wind (2)
- Windenergy (2)
- 2-span bridge (1)
- Achsimpulse (1)
- Acoustic emission testing (1)
- Amplitude-charge weight laws (1)
- Amplitude-distance laws (1)
- Amplituden-Abstands-Gesetze (1)
- Analysis of variance (1)
- Ansys Autodyn (1)
- Apartment building (1)
- Artificial Intelligence (1)
- Artificial intelligence (1)
- Asphalt (1)
- Assessment (1)
- Attenuation (1)
- Automatisierte Fertigung (1)
- Automatisierte schweißtechniche Fertigung (1)
- Axial load bearing (1)
- Axle impulses (1)
- Axle pulses (1)
- Axle-sequence spectrum (1)
- BAM Windenergie Fügetechnik (1)
- Bahngleis (1)
- Ballast track (1)
- Base isolation (1)
- Baugrunddynamik (1)
- Bauwerk-Boden-Wechselwirkung (1)
- Bauwerksmonitoring (1)
- Bauwerksüberwachung (1)
- Bayes'sche Analyse (1)
- Bayesian System Identification (1)
- Bayesian methods (1)
- Bayesian system identification (1)
- Belastungsfahrt (1)
- Belastungszug (1)
- Beulen (1)
- Big Data (1)
- Bionik (1)
- Blast (1)
- Bodenschlitz (1)
- Bodenübertragungsfunktion (1)
- Boreholes (1)
- Boundary element method (1)
- Box-Behnken (1)
- Bridge (1)
- Brücke (1)
- Buckling piles circular shells (1)
- Building information modelling (1)
- Bulging (1)
- CPT (1)
- Cars (1)
- Centerline solidification cracking (1)
- Changing process noise (1)
- Chemisoprtion (1)
- Climate Chamber (1)
- Climate chamber (1)
- Compressive Cyclic loading (1)
- Compressive cyclic loading (1)
- Compressive strength (1)
- Computer Vision (1)
- Concrete (1)
- Crack Luminescence (1)
- Crack formation (1)
- Crack pattern (1)
- Crack repair (1)
- Cracks (1)
- Cyclic axial shearing (1)
- Cyclic degradation (1)
- Cyclic load (1)
- DEM (1)
- DEM-LBM simulation (1)
- DUCON® (1)
- Damage Detection (1)
- Damage identification (1)
- Deckeneigenfrequenzen (1)
- Deckenschwingungen (1)
- Design models (1)
- Design practice (1)
- DiMoWind RDS-PP Maintenance Digital Twin Offshore Wind Energy (1)
- Digital Image Correlation (1)
- Digital Twin (1)
- Digital twin (1)
- Digitalisierung (1)
- Displacements (1)
- Drone (1)
- Drop Test (1)
- Drucker-Prager (1)
- Ductility (1)
- Dynamic soil properties (1)
- Dynamische Bodenkennwerte (1)
- Dämpfung (1)
- E-modulus (1)
- EERA Joint Program (1)
- Earth masonry (1)
- Earthen hydraulic constructions (1)
- Earthen hydraulic infrastructures (1)
- Einflusslinie (1)
- Einflusslinien (1)
- Einfügungsdämmung (1)
- Elastische Gebäudelagerung (1)
- End-of-life decision making (1)
- Energy (1)
- Entscheidungsfindung (1)
- Environmental (1)
- Environmental Effects (1)
- Ermüdungsprüfung (1)
- Ermüdungsschäden (1)
- Erneuerbare Energien (1)
- Erosion of cohesive soils (1)
- Erschütterungen im Fernfeld (1)
- Erschütterungsausbreitung (1)
- Evaluation (1)
- Excitation forces (1)
- Explosion-induced ground vibrations (1)
- Fahrzeug-Fahrweg-Boden-Wechselwirkung (1)
- Faseroptik (1)
- Fatigue deterioration (1)
- Filter effects (1)
- Finite Elemente Simulation (1)
- Finite element models (1)
- Flexibility (1)
- Floors (1)
- Fluid-structure interaction (1)
- Fly ash (1)
- Footbridge (1)
- Force reconstruction (1)
- Freight train (1)
- Frequency response function (1)
- GMNIA (1)
- GNSS (1)
- GPU parallelisation (1)
- Gaussian Process (1)
- Gebäudelagerung (1)
- Gebäudemodelle (1)
- Gebäudeschwingungen (1)
- Gekoppelte Fluid-Partikel Simulationen (1)
- Geomechanics (1)
- Geomechanics of offshore foundations (1)
- Geometrie (1)
- Geotechnical site-characterization (1)
- Gleiströge (1)
- Granular Cohesive Materials, (1)
- Ground (1)
- Ground vibration measurements (1)
- Grout Injection (1)
- Grouted Connection (1)
- Grouted connection (1)
- Grouting (1)
- Halbraum (1)
- High-rise buildings (1)
- High-speed train (1)
- Immission (1)
- Impact damage of reinforced concrete (1)
- Impedanzmethode (1)
- Inertial interaction (1)
- Injection Sequence (1)
- Inspeciton (1)
- Interface (1)
- Interface model (1)
- Irregular ballast (1)
- Irregular soil (1)
- Irregularities (1)
- Jacket support structure (1)
- Jet erosion test (1)
- Kinematic interaction (1)
- Knudsen effect (1)
- Kraft auf den Boden (1)
- LBM-DEM (1)
- LBM-DEM coupling (1)
- Laboratory beam structure (1)
- Laser beam welding (1)
- Lateral load bearing (1)
- Layered soils (1)
- Leichtbauprinzipien (1)
- Lifetime Extension (1)
- Linear parameter varying systems (1)
- Load Test (1)
- Load bearing behaviour (1)
- Long-term shrinkage (1)
- Macromechanical Sample Strength (1)
- Maintal Bridge Gemuenden (1)
- Maintalbrücke Gemünden (1)
- Maintenance Digital Twin Offshore Wind Energy (1)
- Marine geotechnics (1)
- Material Point Method (1)
- Material moisture (1)
- Material tests (1)
- Measurement (1)
- Measurements (1)
- Mechanical challenges (1)
- Messfahrt (1)
- Metakaolin (1)
- Micro silica (1)
- Micro-reinforcement (1)
- Microfine cement (1)
- Micromechanical LBM-DEM simulation (1)
- Micromechanical Tensile Failure (1)
- Micromechanical analysis (1)
- Micromechanical simulation (1)
- Mitigation (1)
- Mix design (1)
- Mobile elements (1)
- Modal Analysis (1)
- Modal load spectrum (1)
- Modal system identification (1)
- Model Update (1)
- Model updating (1)
- Modellierung (1)
- Modes and waves (1)
- Molecular diffusion (1)
- Monopile (1)
- Monopile Buckling (1)
- Movin load test (1)
- Non destructive testing (1)
- Non-Destructive Evaluation (1)
- Non-destructive testing (1)
- Normung (1)
- Numerical analysis (1)
- Numerical model (1)
- Numerical modeling (1)
- Numerical simulation (1)
- Numerical simulation of impact damage (1)
- Numerical simulations (1)
- Offhore (1)
- Office tower (1)
- Offshore Structures (1)
- Offshore Wind (1)
- Offshore Wind Energy (1)
- Offshore Wind Energy Converter (1)
- Offshore Windenergie (1)
- Offshore Windenergy Pile Buckling (1)
- Offshore pile foundations (1)
- Offshore wind energy foundations (1)
- Offshore wind farm (1)
- Offshore wind farms (1)
- Offshore wind-turbine foundations (1)
- Offshore-Wind (1)
- Offshore-Windenergieanlagen (1)
- Offshore-Windkraftanlagen (1)
- Optimal Sensor Placement (1)
- Passenger train (1)
- Pfahlfußbeulen (1)
- Pfahlnachgiebigkeiten (1)
- Physisorption (1)
- Pile Buckling (1)
- Pile Capacity (1)
- Pile Foundation (1)
- Pile ageing (1)
- Pile groups (1)
- Pile retrofit system (1)
- Pile-Tip-Buckling (1)
- Point Cloud (1)
- Post-impact evaluation (1)
- Prediction (1)
- Prediction of explosion induced ground and building vibration (1)
- Predictive maintenance (1)
- Probabilitische Ingenieurmodelle (1)
- Probability of Detection (1)
- Prognose (1)
- Quasi-static and dynamic tests (1)
- Radar (1)
- Railbridge (1)
- Railway bridge (1)
- Railway tracks (1)
- Railway trafiic (1)
- Railway tunnel (1)
- Randelementmethode (1)
- Randomly heterogeneous soil (1)
- Rayleighwellendispersion (1)
- Rechenmodelle (1)
- Rechenverfahren (1)
- Rehabilitation (1)
- Reinforced Concrete Structures (1)
- Reinforced concrete (1)
- Research data management (1)
- Residual evaluation (1)
- Richtige Fahrzeugmasse (1)
- Risiko (1)
- Risikoanalyse (1)
- Risk (1)
- Risk-based maintenance planning (1)
- Rissprozes (1)
- Rissprozess (1)
- SHM Environmental (1)
- Safety (1)
- Scattering (1)
- Schadensdetektion (1)
- Schadensüberwachung (1)
- Schienenfahrweg (1)
- Schienenfahrwege (1)
- Schwingungsbasierte Verfahren (1)
- Schwingungsmonitoring (1)
- Shrinkage (1)
- Simple and fast prediction (1)
- Simulation and experiment (1)
- Site-characterization (1)
- Size effect (1)
- Slenderness effect (1)
- Soil Struture Interaction (1)
- Soil erosion (1)
- Soil properties (1)
- Soil-Structure-Interaction (1)
- Soil-pile interaction (1)
- Soil-wall floor model (1)
- Soil-water-structure interaction (1)
- Spektralanalyse (1)
- Stability Buckling soil-structure-interaction piles offshore (1)
- Stabilität (1)
- Static load (1)
- Statistical correlations (1)
- Statistical tests (1)
- Statistische Korrelationen (1)
- Stereo photogrammetry (1)
- Stochastic Subspace Damage Detection (1)
- Structural Systems (1)
- Structural integrity (1)
- Structural integrity maintenance (1)
- Structural integrity management (1)
- Strukturmonitoring (1)
- Störgrößen (1)
- Subspace methods (1)
- Subspace-based residual (1)
- Substructures (1)
- Suction Bucket (1)
- Supplementary cementitious materials (1)
- Support structures (1)
- Surface line (1)
- Surface-tunnel reduction (1)
- System Identification (1)
- Systemidentifikation (1)
- TOP (1)
- Temperatureinflüsse (1)
- Tensile Capacity (1)
- Time-variant reliability (1)
- Tip Buckling (1)
- Tomographic damage evaluation (1)
- Track damage (1)
- Train configuration (1)
- Train excitation (1)
- Train passages (1)
- Train speed (1)
- Tran speed (1)
- Transfer fuction (1)
- Transmission (1)
- Tunnel line (1)
- Tunnelstrecke (1)
- UHPC (1)
- Umwelteinflüsse (1)
- Un- certainty (1)
- Uncertainty (1)
- Uncertainty in reference (1)
- Unterraummethoden (1)
- Value of Information (1)
- Varying soil stiffness (1)
- Varying track stiffness (1)
- Vibration monitoring (1)
- Vibrations (1)
- Vollraum (1)
- Water-structure interaction (1)
- Wave-Tower interaction (1)
- Wellenausbreitung (1)
- Wellenausbreitung in der Tiefe (1)
- Wellenfeldberechnung (1)
- Wind Energy Structures (1)
- Wind Turbines (1)
- Wind energy (1)
- Wind turbines (1)
- Wind-farm aerodynamics (1)
- Windfarm wake analysis (1)
- Zuggeschwindigkeit (1)
- elastische Gebäudelagerungen (1)
- risk, reliability, inspection planning, offshore wind turbines (1)
- zerstreute Achslastimpulse (1)
- Übertragungsmatrizen (1)
- Überwachung (1)
Organisationseinheit der BAM
- 7.2 Ingenieurbau (169) (entfernen)
Eingeladener Vortrag
- nein (169) (entfernen)
As many wind turbines approach the end of their design lifetime, from a technical point of view, comprehensive fatigue analysis of all critical parts is necessary to decide what comes after – continued operation, repowering, or decommissioning. Typically, it is a two-stage evaluation process consisting of a physical inspection of the structure and an analytical part to compare the design and actually experienced loading conditions. Structural health monitoring helps to reduce the uncertainties in the estimations by providing insight into deviations between the designed and the built structure. Furthermore, it allows the evaluation of the consumed fatigue lifetime by analyzing the strain measurements that mirror the actual structural response to experienced environmental and operational conditions. However, the measurement values are limited to a sparse number of instrumented spots on the structure, and further extrapolation to the non-instrumented (critical) sections is required to perform a complete fatigue assessment. One known approach is the external force reconstruction, which has only scarcely been considered for application in offshore wind turbines. In order to extend the previously developed thrust force reconstruction framework, this work discusses the possibilities and challenges of wind and wave loading reconstruction in offshore wind turbine support structures.
Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q 0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites.
Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory.
This article presents a solid cohesion model for the simulation of bonded granular assemblies in the frame of 3D discrete element approaches (DEM). A simple viscoplastic cohesion model for 2D geometries is extended to 3D conditions, while its yield criterion is generalized as a hyper-surface in the space of bond solicitations to include torsional moments. The model is then calibrated using experimental results of uniaxial traction at both the microscopic and macroscopic scales with an artificial granular cohesive soil. The paper finally presents some simulated results on the macromechanical sample traction application and briefly discusses the model's current limitations and promising prospects for subsequent works.
Wir zeigen, dass bei homogenen ausgeprägt sandartigen Böden mit statistisch ermittelten Korrelationen die dynamischen Bodensteifigkeiten mit einer Genauigkeit abgeschätzt werden können, die mit der Ungenauigkeit der seismischen Verfahren übereinstimmt. Mit zunehmenden Feinkornanteil werden die Unsicherheiten der statistischen Korrelationen größer. Bei stark überkonsolidierten glazialen Böden sollte von der Anwendung empirischer Korrelationen Abstand genommen werden.
Current standards like ISO 14837-32:2015 and DIN EN 1998-1/NA:2021 as well as prEN 1997-2:2022 allow for using correlations between the results of in-situ soil penetration tests and shear wave velocity (or shear modulus) to determine soil properties to be used in dynamic analyses. While the ISO and prEN standards even provide some recommendations on specific correlations to be used, the DIN standard does not. Due to the statistical nature of such correlations their general applicability has to be verified. We collected data sets from test sites from Germany as well as New Zealand at which cone penetration tests (CPT) as well as seismic site investigation methods were conducted. These sites comprise sandy soils as well as clayey soils, mixed soils as well as glacial soils. We compare the results of several correlations between CPT results and shear wave velocity. The accuracy of such correlations is assessed with respect to the accuracy of seismic in-situ tests. It turns out that for clean sands such correlations between CPT and Vs have a similar order of variability as seismic in-situ tests conducted at the same site. The higher the fines portion of the soil, the higher the variability of the statistical correlations, and consequently the less the general applicability. For glacial soils and other special soil types usage of statistical correlations to determine dynamic soil properties is not recommended.
Nowadays geotechnical engineering firms have powerful software tools to extent their consulting business also into dynamic soil-structure interaction, which before has been restricted to a rather small community of specialized experts in this field, and they certainly do. This is particularly true with respect to non-seismic sources, that is all kinds of human induced vibrations. Hence, there is a demand from clients as well as from contractors to have guidance on the requirements as well as the limits of numerical modelling of soil-structure interaction. From the literature as well as from relevant standards, recommendations for the numerical modelling of soil-structure interaction problems involving seismic actions are well known, e. g. ASCE/SEI 4-16. There are, however, some particularities when dealing with human-induced vibrations, which are absent in seismic analyses. For human-induced excitations very little specific guidance has been published in the past. A machine foundation on a homogeneous half space excited by harmonic loads with excitation frequency between 4 Hz and 64 Hz has been analysed by means of several commercially available software packages. Parametric studies have been performed to verify if recommendations for seismic soil-structure analyses are valid for non-seismic analyses as well. This paper provides details on the benchmark example and the most important conclusions from the undertaken parametric studies.
Identifying optimal inspection and repair strategies for offshore jacket structures is a challenging task. We pre-sent an approach, which is based on recent developments in the field of risk-based operation and maintenance planning at the structural system level. The approach utilizes heuristics to define inspection and repair strate-gies at the system level and to reduce the search space of possible strategies. For each defined strategy, the expected service life cost of inspection, repair and failure is evaluated based on simulated inspection and re-pair histories. Subset simulation is applied to compute the conditional repair and failure probabilities required for this analysis. It also forms the basis for simulating inspection and repair histories. The strategy that mini-mizes the expected service life cost is the optimal one in the set of pre-selected strategies. The underlying condition and performance model accounts for the stochastic dependence among the deterioration states of the different structural elements and the structural redundancy. The approach is demonstrated in a case study considering a jacket-type frame. In this study, we essentially vary the inspection interval, the minimum num-ber of inspected components and the target reliability, and identify the combination that minimizes the ex-pected total service life cost.
Die Risikoanalyse ist ein formales Verfahren zur Unterstützung von Entscheidungen unter Unsicherheit und Risiko. Es ermöglicht eine Optimierung von Maßnahmen zur Verhinderung unerwünschter Konsequenzen. Der Vortrag stellt die aktuellen Aktivitäten an der BAM in dem Feld Risikoanalyse technischer System vor.
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.
The EU member states have set out ambitious long-term goals for deploying offshore wind energy. The installed offshore wind capacity is set to increase from 14.6 GW in 2021 to around 320 GW in 2050. This signifies the role of offshore wind energy as a major contributor to reaching the EU’s climate and energy goals. To ensure that the defined targets are met, a significant number of new wind farms has to be installed and existing wind farms reaching the end of their planned life need to be reused efficiently. Some of the relevant reuse alternatives are lifetime extension, repowering based on the existing support structures and repowering with new turbines.
As a basis of the decision-making regarding the reuse of existing offshore wind farm, the expected utility of each relevant option should be determined based on the associated expected rewards, costs and risks. The optimal concept maximizes the utility of the decision-maker and fulfills the existing constraints and requirements. To facilitate such a quantitative decision-making, models and methods have to be developed. In particular, models are required that enable predictions of (a) the condition and performance of the turbines and support structures and (b) the renumeration, costs and consequences of adverse events. These predictions have to consider (a) the governing uncertainties, (b) the available information from the planning, construction, installation and operating phase, (b) potential repair, retrofitting and strengthening schemes and (c) possible monitoring, inspection and maintenance regimes for the future operating phase.
Over the past years, several models, methods and tools have been developed at the Bundesanstalt für Materialforschung und -prüfung (BAM) to support the structural integrity management of offshore wind turbine substructures. These include:
(a) a prototype for reliability-based, system-wide, adaptive planning of inspections of welded steel structures in offshore wind farms,
(b) a method for monitoring and risk-informed optimization of inspection and maintenance strategies for jacket structures subject to fatigue, and
(c) a probabilistic cost model of inspection and maintenance of welded steel structures in offshore wind farms.
This contribution provides an overview on these works and discusses how they can be adapted and extended to support the decision-making regarding lifetime extensions and repowering of offshore wind farms.
The Bundesanstalt für Materialforschung und -prüfung (BAM) collaborates with TNO to develop a software framework for automated calibration of structural models based on monitoring data. The ultimate goal is to include such models in the asset management process of engineering structures. As a basis for developing the framework, a multi-span road bridge consisting of ten simply supported steel box girders was selected as a test case. Our group measured output-only vibration data from one box girder under ambient conditions. From the data, we determined eigenfrequencies and mode shapes. In parallel, we developed a preliminary structural model of the box girder for the purpose of predicting its modal properties. In this contribution, we provide an overview of the measurement campaign, the operational modal analysis, the structural modeling and qualitatively compare the identified with the predicted modes. As an outlook, we discuss the further steps in the calibration process and future applications of the calibrated model.
Im AISTEC Projekt erforscht der FB 7.2 Verfahren zur Bewertung von Verkehrsbrücken auf der Gruandlage von sensorbasierten Bauwerksmessungen. In diesem Vortrag wird ein Überlick über die Forschungsarbeiten des FB 7.2 präsentiert. Des Weiteren wird ein Ausblick zur quantitativen Integration von sensorbasierten Bauwerksmessungen in die risiko-basierte prädiktive Planung von Inspektionen und Reparaturen von Ingenieurbauwerken gegeben.
Fatigue is one of the main deterioration processes affecting the performance of welded steel support structures of wind turbines in offshore wind farms. In this contribution, we present a probabilistic physics-based fatigue deterioration model of a wind farm that accounts for the stochastic dependence among the fatigue behavior of different hotspots at turbine and wind farm level. The dependence exists because of uncertain common influencing factors such as similar material properties, fabrication qualities and load conditions. These system effects signify that an inspection of one hotspot provides indirect information of the condition of the remaining hotspots and thus enable an optimization of the inspection effort for a wind farm.
The wind farm model consists of two levels: A turbine support structure (level 1 system model) is represented by its fatigue hotspots and their stochastic dependence. The fatigue performance of a hotspot is described by a probabilistic fracture mechanics (FM) fatigue model. The probabilistic model of the parameters of the FM fatigue model is calibrated based on design data and is thus directly linked to the design of the turbine support structures. Dependence among the fatigue performances of different hotspots in a turbine support structure is modeled by introducing correlations between the stochastic parameters of the FM fatigue models. A wind farm (level 2 system model) consists of different turbine support structures (level 1 system models). Additional correlations are introduced at wind farm level to account for the dependence among the fatigue behavior of hotspots belonging to different turbine support structures. The wind farm model enables the computation of (marginal) hotspot fatigue reliabilities, system fatigue reliabilities of individual turbine support structures and the system fatigue reliability of an entire wind farm. The probabilistic model of the parameters of the two-level system model can be consistently updated with inspection outcomes using Bayesian methods. The updated probabilistic model of the model parameters then forms the basis for updating the estimates of the fatigue reliabilities.
We implement the wind farm model in a software tool named SysPark. The tool provides the means for planning inspections at wind farm level using an adaptive reliability-based threshold approach. In this approach, the first inspection campaign is planned in the year before the fatigue failure rates of the hotspots with the lowest fatigue reliabilities exceed a threshold failure rate. Once inspection results become available, the probabilistic model of the parameters of the wind farm model is updated. If repairs are performed, the wind farm model is additionally modified to describe the behavior of the repaired hotspots. The updated and modified model then enables the planning of the next inspection campaign and so on. The software tool is demonstrated in a case study considering a generic wind farm consisting of turbines with jacket support structures.
The reliability of deteriorating structures at time t is quantified by the probability that failure occurs within the period leading up to time t. This probability is often referred to as cumulative failure probability and is equal to the cumulative distribution function of the time to failure. In structural reliability, an estimate of the cumulative failure probability is obtained based on probabilistic engineering models of the deterioration processes and structural performance. Information on the condition and the loading contained in inspection and monitoring data can be included in the probability estimate through Bayesian updating. Conditioning the probability of failure on the inspection or monitoring outcomes available at time t (e.g. detections or no detection of damages) can lead to a reduction in that probability.
Such a drop in the cumulative failure probability might seem counterintuitive since the cumulative failure probability is a non-decreasing function of time. In this paper, we illustrate—with the help of a numerical example—that such a drop is possible because the cumulative probability before and after the updating is not based on the same information, hence not on the same probabilistic model.