7.2 Ingenieurbau
Filtern
Dokumenttyp
- Vortrag (171)
- Beitrag zu einem Tagungsband (83)
- Zeitschriftenartikel (68)
- Posterpräsentation (10)
- Buchkapitel (4)
- Dissertation (4)
- Beitrag zu einem Sammelband (3)
- Sonstiges (2)
- Tagungsband (Herausgeberschaft für den kompletten Band) (1)
Sprache
- Englisch (261)
- Deutsch (84)
- Mehrsprachig (1)
Schlagworte
- Structural Health Monitoring (26)
- Ground vibration (20)
- Structural health monitoring (15)
- Fatigue (14)
- Brücken (11)
- Monitoring (11)
- Offshore (11)
- Offshore wind energy (11)
- Hammer impact (9)
- Impact (9)
- Train passage (9)
- Damage characterization (8)
- Model interpolation (8)
- Planar tomography (8)
- SHM (8)
- Structural systems (8)
- Vibration measurements (8)
- Building vibration (7)
- Damage detection (7)
- Deterioration (7)
- Layered soil (7)
- Reliability (7)
- Slab track (7)
- Soil-structure interaction (7)
- Train-induced ground vibration (7)
- Bahnerschütterungen (6)
- Compressive strength (6)
- Design methods (6)
- Grout (6)
- Inspection (6)
- Numerical modelling (6)
- Offshore wind turbines (6)
- Physical phenomenology (6)
- Pile foundations (6)
- Reinforced concrete structure (6)
- Datenmanagement (5)
- Environmental effects (5)
- Interface (5)
- Layered soils (5)
- Modalanalyse (5)
- Numeric simulation (5)
- Repair (5)
- Temperature rejection (5)
- Ultrasonic testing (5)
- Vibration (5)
- Windenergie (5)
- Bayesian updating (4)
- Container loading (4)
- Crack detection (4)
- Damage localization (4)
- Drop test (4)
- Erosion (4)
- Erschütterungen (4)
- Erschütterungsminderung (4)
- Excitation forces (4)
- Fault detection (4)
- Foundation load (4)
- Foundations (4)
- Gründungsstrukturen (4)
- High-strength concrete (4)
- Inspection planning (4)
- Mitigation (4)
- Offshore geomechanics (4)
- Probabilistic (4)
- Shell Buckling (4)
- Statistical tests (4)
- Steel structures (4)
- Subspace methods (4)
- Subspace-based method (4)
- Tunnel (4)
- Vehicle-track-soil interaction (4)
- Vibration measurement (4)
- Wind (4)
- Wind Energy (4)
- Ansys Autodyn (3)
- Attenuation (3)
- Axle impulses (3)
- BIM (3)
- Bauwerksüberwachung (3)
- Belastungsversuch (3)
- Box-Behnken (3)
- Bridge (3)
- Bridges (3)
- Brücke (3)
- Buckling (3)
- Compaction Grouting (3)
- Cracks (3)
- DUCON® (3)
- Deep foundations (3)
- Dispersionsmessung (3)
- Drucker-Prager (3)
- Ductility (3)
- E-modulus (3)
- Earth masonry (3)
- Elastische Gleiselemente (3)
- Emission (3)
- Erschütterungsprognose (3)
- Filter effects (3)
- Fly ash (3)
- Grouted connection (3)
- Grouting (3)
- Großer Fallturm Horstwalde (3)
- Irregular soil (3)
- Leichtbau (3)
- Linear parameter varying systems (3)
- Load vector (3)
- Maintenance (3)
- Material moisture (3)
- Metakaolin (3)
- Micro-reinforcement (3)
- Micromechanical modelling (3)
- Mobile elements (3)
- Model updating (3)
- Monopiles (3)
- Numerical modeling (3)
- Offshore Pile Foundation (3)
- Offshore Windenergieanlagen (3)
- Offshore foundations (3)
- Offshore wind turbine (3)
- Physical testing (3)
- Post-impact evaluation (3)
- Quasi-static and dynamic tests (3)
- Railway (3)
- Railway bridge (3)
- Randomly heterogeneous soil (3)
- Rehabilitation (3)
- Reinforced concrete (3)
- Risk (3)
- Scattering (3)
- Schwingungsdynamik (3)
- Soil erosion (3)
- Soil properties (3)
- Statistical evaluation (3)
- Statistical method (3)
- Stereo photogrammetry (3)
- Subspace-based residual (3)
- Temperature effects (3)
- Train speed (3)
- UHPC (3)
- Umwelteinflüsse (3)
- Vehicle-track interaction (3)
- Vibrations (3)
- Wellenausbreitung (3)
- Wellengeschwindigkeit (3)
- Zivile Sicherheit (3)
- 2-span bridge (2)
- AISTEC (2)
- Acceleration sensors (2)
- Achsfolgespektren (2)
- Acoustic emission testing (2)
- Amplitude-charge weight laws (2)
- Amplitude-distance laws (2)
- Analysis of variance (2)
- Apartment building (2)
- Artificial Intelligence (2)
- Artificial intelligence (2)
- Automatisierte schweißtechnische Fertigung (2)
- Axle sequence (2)
- Axle-sequence spectrum (2)
- Ballast track (2)
- Bauteile (2)
- Bauwerke (2)
- Bauwerksmonitoring (2)
- Bayes'sche Analyse (2)
- Bayesian System Identification (2)
- Bayesian analysis (2)
- Bayesian methods (2)
- Bayesian system identification (2)
- Bemessung (2)
- Big Data (2)
- Bitumen (2)
- Blast (2)
- Bodenübertragungsfunktion (2)
- Cable failure (2)
- Cable-stayed bridge (2)
- Changing process noise (2)
- Chemisoprtion (2)
- Climate chamber (2)
- Compressive Cyclic loading (2)
- Compressive cyclic loading (2)
- Computer Vision (2)
- Concrete (2)
- Coupled fluid-particle simulation (2)
- Coupler systems (2)
- Crack Luminescence (2)
- Crack formation (2)
- Crack pattern (2)
- Cyclic load (2)
- DEM (2)
- Damage identification (2)
- Design (2)
- Digital twin (2)
- Digitalisierung (2)
- Displacements (2)
- Drone (2)
- Earth block masonry (2)
- Elastische Elemente (2)
- Elastische Gebäudelagerung (2)
- Energy (2)
- Erschütterungsausbreitung (2)
- Evaluation (2)
- Explosion-induced ground vibrations (2)
- Faseroptik (2)
- Feuchte (2)
- Finite Elemente Simulation (2)
- Finite element models (2)
- Freight train (2)
- GPU parallel computation (2)
- Gaussian Process (2)
- Geotechnical site-characterization (2)
- Gleiströge (2)
- Ground vibration measurements (2)
- Grouted Connection (2)
- Halbraum (2)
- High-performance computing (2)
- High-speed (2)
- High-speed train (2)
- Immission (2)
- Injection Sequence (2)
- Irregular ballast (2)
- Irregularities (2)
- Jacket support structure (2)
- Jet erosion test (2)
- Klimakammer (2)
- Knudsen effect (2)
- LBM-DEM (2)
- Laboratory beam structure (2)
- Lehm (2)
- Long-term shrinkage (2)
- Luminescence (2)
- Macromechanical Sample Strength (2)
- Material tests (2)
- Mauerwerk (2)
- Measurement (2)
- Measurements (2)
- Messen im Bauwesen (2)
- Micro silica (2)
- Micromechanical Tensile Failure (2)
- Mix design (2)
- Modal Analysis (2)
- Moisture (2)
- Moisture content (2)
- Molecular diffusion (2)
- Non destructive testing (2)
- Non-Destructive Evaluation (2)
- Non-destructive testing (2)
- Numerical model (2)
- Numerical simulations (2)
- Office tower (2)
- Offshore Wind (2)
- Offshore Wind Energy (2)
- Offshore Windenergy Pile Buckling (2)
- Offshore geotechnics (2)
- Offshore wind (2)
- Offshore-Windenergieanlagen (2)
- Optimal Sensor Placement (2)
- Passenger train (2)
- Physisorption (2)
- Pile Foundation (2)
- Pile Tip Buckling (2)
- Prediction (2)
- Prediction of explosion induced ground and building vibration (2)
- Probability of Detection (2)
- Prädiktive Instandhaltung (2)
- Radar (2)
- Railway tunnel (2)
- Railways (2)
- Rechenmodelle (2)
- Reinforcement (2)
- Relative humidity (2)
- Repowering (2)
- Research data management (2)
- Residual evaluation (2)
- Resonance (2)
- Risslumineszenz (2)
- SDDLV (2)
- Safety (2)
- Scattered axle impulses (2)
- Schadensdetektion (2)
- Schwingungsbasierte Verfahren (2)
- Size effect (2)
- Slenderness effect (2)
- Soil-Structure-Interaction (2)
- Soil-pile interaction (2)
- Soil-wall-floor model (2)
- Static axle loads (2)
- Static load (2)
- Strength (2)
- Strukturmonitoring (2)
- Suction bucket (2)
- Supplementary cementitious materials (2)
- Surface-tunnel reduction (2)
- System Identification (2)
- System identification (2)
- Tensile Capacity (2)
- Time-variant reliability (2)
- Tomographic damage evaluation (2)
- Track damage (2)
- Track-soil interaction (2)
- Train excitation (2)
- Transmission (2)
- Uncertainty (2)
- Uncertainty in reference (2)
- Uncertainty quantification (2)
- Unterraummethoden (2)
- Value of Information (2)
- Vehicle–track interaction (2)
- Verkehrsinfrastukturen (2)
- Vollraum (2)
- Wellenausbreitung in der Tiefe (2)
- Wind Turbines (2)
- Wind energy (2)
- Wind turbine tower (2)
- Windenergieanlagen (2)
- Windenergy (2)
- Zuggeschwindigkeit (2)
- Zuverlässigkeit (2)
- 3D imaging (1)
- Achsimpulse (1)
- Acoustic emission (1)
- Acoustic emission analysis (1)
- Ambient excitation (1)
- Amplituden-Abstands-Gesetze (1)
- Analytical Design Methods (1)
- Asphalt (1)
- Assessment (1)
- Asymptotic local approach (1)
- Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases (1)
- Automated operational modal analysis (1)
- Automatic modal parameters identification (1)
- Automatisierte Fertigung (1)
- Automatisierte schweißtechniche Fertigung (1)
- Autonomous underwater vehicles (1)
- Axial load bearing (1)
- Axle loads (1)
- Axle pulses (1)
- BAM Windenergie Fügetechnik (1)
- Bahngleis (1)
- Base isolation (1)
- Baugrunddynamik (1)
- Bauwerk-Boden-Wechselwirkung (1)
- Bauwerksdiagnostik (1)
- Beanspruchungszustand (1)
- Belastungsfahrt (1)
- Belastungstest (1)
- Belastungszug (1)
- Benchmark (1)
- Beschleunigungssensoren (1)
- Beton (1)
- Betonautobahn (1)
- Betonautobahnen (1)
- Beulen (1)
- Bewertung (1)
- Bionik (1)
- Blast tests (1)
- Bodenschlitz (1)
- Bodenvariabilität (1)
- Boreholes (1)
- Boundary element (1)
- Boundary element method (1)
- Bridge monitoring (1)
- Bridge resonance (1)
- Bridge vibration (1)
- Bruchlastwechselzahlen (1)
- Brückensicherheit (1)
- Buckling piles circular shells (1)
- Buckling soil-structure-interaction offshore piles track (1)
- Building Information Modeling (1)
- Building and Construction (1)
- Building information modelling (1)
- Building response (1)
- Bulging (1)
- CFD (1)
- CPT (1)
- Cancellation (1)
- Cars (1)
- Cement-based composites (1)
- Cemented soil (1)
- Centerline solidification cracking (1)
- Chemisorption (1)
- Civil and Structural Engineering (1)
- Civil structures (1)
- Climate Chamber (1)
- Coating (1)
- Cohesive granular materials (1)
- Cohesive soils (1)
- Column/wall resonance (1)
- Combined finite-element boundary-element method (1)
- Compaction grouting (1)
- Compliance function (1)
- Components of excitation (1)
- Compression tests (1)
- Computational (1)
- Condensed Matter Physics (1)
- Conductor (1)
- Continuous soil (1)
- Continuously inhomogeneous geological media (1)
- Continuously inhomogeneous soils (1)
- Crack (1)
- Crack damage detection (1)
- Crack growth (1)
- Crack repair (1)
- Cyber security (1)
- Cyclic axial shearing (1)
- Cyclic degradation (1)
- DEM-LBM simulation (1)
- Damage Detection (1)
- Damage Identification (1)
- Damage evolution (1)
- Decision matrix analysis (1)
- Deckeneigenfrequenzen (1)
- Deckenschwingungen (1)
- Design models (1)
- Design practice (1)
- Detection (1)
- DiMoWind RDS-PP Maintenance Digital Twin Offshore Wind Energy (1)
- Digital Image Correlation (1)
- Digital Image Correlation (DIC) (1)
- Digital Models (1)
- Digital Twin (1)
- Digitale Zwillinge (1)
- Discrete Element Method (1)
- Discrete element method (1)
- Drop Test (1)
- Drop Tests (1)
- Drop tower (1)
- Druckfestigkeit (1)
- Druckschwellenversuch (1)
- Dynamic axle loads (1)
- Dynamic excitation (1)
- Dynamic loads (1)
- Dynamic soil properties (1)
- Dynamische Bodenkennwerte (1)
- Dynamische Bodensteifigkeit (1)
- Dämpfung (1)
- EERA Joint Program (1)
- Earth (1)
- Earth blocks (1)
- Earth material (1)
- Earthen hydraulic constructions (1)
- Earthen hydraulic infrastructures (1)
- Einflusslinie (1)
- Einflusslinien (1)
- Einfügungsdämmung (1)
- End-of-life decision making (1)
- Entscheidungsfindung (1)
- Environmental (1)
- Environmental Effects (1)
- Environmental and Operational Variability (1)
- Environmental changes (1)
- Environmental influence (1)
- Erhaltungsmanagement (1)
- Ermüdung (1)
- Ermüdungsprüfung (1)
- Ermüdungsschäden (1)
- Ermüdungsverhalten (1)
- Erneuerbare Energien (1)
- Erosion of cohesive soils (1)
- Erschütterungen im Fernfeld (1)
- Estimation (1)
- FEM (1)
- FEM analysis (1)
- Fahrzeug-Fahrweg-Boden-Wechselwirkung (1)
- Fallturm (1)
- Fatigue damage (1)
- Fatigue deterioration (1)
- Fatigue strength (1)
- Fault detectionchanging (1)
- Features (1)
- Fequency domain (1)
- Fiber optic sensing (1)
- Fibre optic sensors (1)
- Finite element (1)
- Finite element analysis (1)
- Finite element method (1)
- Finite element model updating (1)
- Finite elements (1)
- Finite-Elemente-Modellkalibrierung (1)
- Finite-element boundary-element method (1)
- Flexibility (1)
- Flexible car body (1)
- Flexible wheelset (1)
- Floor resonance (1)
- Floors (1)
- Fluid Dynamics (1)
- Fluid-structure interaction (1)
- Fluidized beds (1)
- Footbridge (1)
- Force reconstruction (1)
- Foundation Pile (1)
- Foundation reliability analysis (1)
- Freileitung (1)
- Frequency response function (1)
- GMNIA (1)
- GNSS (1)
- GPA (1)
- GPU Parallel computing (1)
- GPU parallelisation (1)
- Gebäudelagerung (1)
- Gebäudemodelle (1)
- Gebäudeschwingungen (1)
- Gekoppelte Fluid-Partikel Simulationen (1)
- General Materials Science (1)
- Geology (1)
- Geomechanics (1)
- Geomechanics of offshore foundations (1)
- Geometric vehicle and track irregularities (1)
- Geometrie (1)
- Global ambient vibrations (1)
- Granular Cohesive Materials (1)
- Granular Cohesive Materials, (1)
- Granular cohesion (1)
- Granular materials (1)
- Ground (1)
- Grout Injection (1)
- HAZID (1)
- HTLS (1)
- Hard impact (1)
- Harter Anprall an Stahlbetonstrukturen (1)
- High-Rise Building (1)
- High-rise building (1)
- High-rise buildings (1)
- Horizontal stress (1)
- Horizontal wind turbine (1)
- Hydraulic jet erosion (1)
- IEPE (1)
- Impact damage of reinforced concrete (1)
- Impact damage on reinforced concrete (1)
- Impact loading (1)
- Impakt (1)
- Impedanzmethode (1)
- Imperfektion (1)
- Impinging jet (1)
- Inclination angle (1)
- Inertial Interaction (1)
- Inertial interaction (1)
- Inhomogeneous soils (1)
- Innovative Messtechnik (1)
- Inspeciton (1)
- Inspektion (1)
- Instandhaltung (1)
- Interface model (1)
- Jet impingement (1)
- Kalibrierung (1)
- Kinematic Interaction (1)
- Kinematic interaction (1)
- Kraft auf den Boden (1)
- LBM-DEM coupling (1)
- LBM-DEM simulation (1)
- Laminar flow (1)
- Laminography (1)
- Large components (1)
- Laser beam welding (1)
- Lateral dynamic displacement (1)
- Lateral load bearing (1)
- Lattice Boltzmann Method (1)
- Lattice Boltzmann method (1)
- Leichtbauprinzipien (1)
- Lifetime Extension (1)
- Load Test (1)
- Load bearing behaviour (1)
- Load identification (1)
- Load tests (1)
- Load-bearing (1)
- Load-bearing behaviour (1)
- Local approaches (1)
- Long-span bridge (1)
- Low-frequency shaker (1)
- MEMS (1)
- Maintal Bridge Gemuenden (1)
- Maintalbrücke Gemünden (1)
- Maintenance Digital Twin Offshore Wind Energy (1)
- Marine geomechanics (1)
- Marine geotechnics (1)
- Maschinenbetrieb (1)
- Maschinenfundament (1)
- Material Point Method (1)
- Material Point Method (MPM) (1)
- Material model (1)
- Measurement campaigns (1)
- Mechanical challenges (1)
- Merkblatt (1)
- Messfahrt (1)
- Microfine Cement (1)
- Microfine cement (1)
- Micromechanical LBM-DEM simulation (1)
- Micromechanical analysis (1)
- Micromechanical simulation (1)
- Microsilica (1)
- Minderungsmaßnahmen (1)
- Mixed formulation (1)
- Modal analysis (1)
- Modal force spectrum (1)
- Modal load spectrum (1)
- Modal system identification (1)
- Model Building (1)
- Model Update (1)
- Model Updating (1)
- Model update (1)
- Modell-Update (1)
- Modellierung (1)
- Modes (1)
- Modes and waves (1)
- Modulus of elasticity (1)
- Monitoring-informed inspection and maintenance planning (1)
- Monopile (1)
- Monopile Buckling (1)
- Monopile installation risks (1)
- Movin load test (1)
- Multi-beam method (1)
- Multi-beam track model (1)
- Multiple impact (1)
- NDT (1)
- Nachgiebigkeiten (1)
- Nelson’s method (1)
- Normung (1)
- Numerical analysis (1)
- Numerical damage simulation (1)
- Numerical simulation (1)
- Numerical simulation of impact damage (1)
- Numerische Analysen (1)
- Obstacles (1)
- Offhore (1)
- Office building (1)
- Offshore Structures (1)
- Offshore Wind Energy Converter (1)
- Offshore Windenergie (1)
- Offshore pile foundation (1)
- Offshore pile foundations (1)
- Offshore steel structures (1)
- Offshore wind energy foundations (1)
- Offshore wind farm (1)
- Offshore wind farms (1)
- Offshore wind-turbine foundations (1)
- Offshore-Wind (1)
- Offshore-Windenergie (1)
- Offshore-Windkraftanlagen (1)
- Operational modal analysis (1)
- Optimal sensor placement (1)
- Optimierungsmethoden (1)
- Optimization techniques (1)
- Perfectly Matched Layer (PML) (1)
- Pfahlfußbeulen (1)
- Pfahlnachgiebigkeiten (1)
- Physisoprtion (1)
- Piaui state (1)
- Pile Buckling (1)
- Pile Capacity (1)
- Pile ageing (1)
- Pile bending stiffness (1)
- Pile foundation (1)
- Pile groups (1)
- Pile retrofit system (1)
- Pile-Tip-Buckling (1)
- Point Cloud (1)
- Predictive maintenance (1)
- Pressure (1)
- Probabilistic modelling (1)
- Probabilitische Ingenieurmodelle (1)
- Probability of detection (1)
- Probekörpergeometrien (1)
- Process noise (1)
- Prognose (1)
- Propagation from a tunnel (1)
- Quasi-static response; (1)
- Rail roughness (1)
- Railbridge (1)
- Railway induced vibration (1)
- Railway track (1)
- Railway tracks (1)
- Railway trafiic (1)
- Randelementmethode (1)
- Random dynamics and vibrations (1)
- Random stiffness variation (1)
- Rayleighwellendispersion (1)
- Rechenverfahren (1)
- Recovery experiments (1)
- Referenzbeispiel (1)
- Referenzkennzeichnungssystem (1)
- Reinforced Concrete Structures (1)
- Remote sensing vibrometer (1)
- Residential building (1)
- Richtige Fahrzeugmasse (1)
- Richtlinie (1)
- Rigid vehicle model (1)
- Risiko (1)
- Risikoanalyse (1)
- Risk-based design (1)
- Risk-based maintenance planning (1)
- Rissprozes (1)
- Rissprozess (1)
- SHCC (1)
- SHM Environmental (1)
- SHM environmental bridges (1)
- Sandstone (1)
- Santa-marta (1)
- Scaling (1)
- Schadensüberwachung (1)
- Schallemission (1)
- Scherwellengeschwindigkeit (1)
- Schienenfahrweg (1)
- Schienenfahrwege (1)
- Schrauben (1)
- Schubmodul (1)
- Schwingungsmessungen (1)
- Schwingungsmonitoring (1)
- Schädigungsprozesse (1)
- Sensitivity vectors (1)
- Serra da cangalha (1)
- Shearing (1)
- Shell buckling (1)
- Shrinkage (1)
- Shrinkage Reducing Admixture (1)
- Sicherheit (1)
- Simple and fast prediction (1)
- Simple prediction (1)
- Simulation and experiment (1)
- Site-characterization (1)
- Soft impact (1)
- Soft track elements (1)
- Soil Struture Interaction (1)
- Soil classification (1)
- Soil forces (1)
- Soil stiffness (1)
- Soil-building interaction (1)
- Soil-building resonance (1)
- Soil-wall floor model (1)
- Soil-water-structure interaction (1)
- Sorption isotherm (1)
- Spannbeton (1)
- Spannstahlbruch (1)
- Spatially varying ground conditions (1)
- Spektralanalyse (1)
- Stability Buckling soil-structure-interaction piles offshore (1)
- Stabilität (1)
- State of stress (1)
- Static loading (1)
- Statistical correlations (1)
- Statistical pattern recognition (1)
- Statistische Auswertung (1)
- Statistische Korrelationen (1)
- Stiffness variation (1)
- Stochastic Subspace Damage Detection (1)
- Strain (1)
- Stress stiffening (1)
- Stress-strain relation (1)
- Stress–strain-relation (1)
- Structural Systems (1)
- Structural integrity (1)
- Structural integrity maintenance (1)
- Structural integrity management (1)
- Structural system identification (1)
- Störgrößen (1)
- Substructures (1)
- Suction Bucket (1)
- Superplasticizer (1)
- Supplementary Cementitious Materials (1)
- Support structures (1)
- Surface Foundation (1)
- Surface line (1)
- Sustainable binders (1)
- Switch (1)
- Systemidentifikation (1)
- TOP (1)
- TRC (1)
- Tagung (1)
- Temperature effect (1)
- Temperature effect rejection (1)
- Temperature modeling (1)
- Temperatureinflüsse (1)
- Tensile test (1)
- Test specification (1)
- Tip Buckling (1)
- Track and vehicle irregularities (1)
- Track beam (1)
- Track damage monitoring (1)
- Track damage quantification (1)
- Track deflection (1)
- Track displacements (1)
- Track filter (1)
- Track filtering (1)
- Track vibration (1)
- Tragfähigkeit (1)
- Tragstrukturen (1)
- Train configuration (1)
- Train passages (1)
- Train-induced vibration (1)
- Tran speed (1)
- Transfer fuction (1)
- Transfer function (1)
- Transverse butt weld (1)
- Trench (1)
- Truss structures (1)
- Tunnel line (1)
- Tunnel-pile transfer (1)
- Tunnel-to-surface reduction (1)
- Tunnelstrecke (1)
- Turnout (1)
- UAS (1)
- Un- certainty (1)
- Unbounded domain (1)
- Under-sleeper pads (1)
- Value of information (1)
- Variational Bayesian statistics (1)
- Varying soil stiffness (1)
- Varying stiffness (1)
- Varying track stiffness (1)
- Vibration analysis (1)
- Vibration excitation (1)
- Vibration monitoring (1)
- Viscosity (1)
- Vorspannung (1)
- Wahrscheinlichkeit (1)
- Water Science and Technology (1)
- Water-structure interaction (1)
- Wave propagation (1)
- Wave-Tower interaction (1)
- Wavenumber domain (1)
- Wavenumber integrals (1)
- Wavenumber method (1)
- Waves (1)
- Weld imperfections (1)
- Welded (1)
- Wellenfeldberechnung (1)
- Wheelset (1)
- Wheelset accelerations (1)
- Wind Energy Structures (1)
- Wind energy tower (1)
- Wind turbines (1)
- Wind-farm aerodynamics (1)
- Windenergieanlage (1)
- Windfarm wake analysis (1)
- Workability (1)
- Zerstreute Achsimpulse (1)
- acceleration sensors (1)
- building information modelling (1)
- calibration (1)
- elastische Gebäudelagerungen (1)
- environmental influences (1)
- fachwerkartige Stahltragwerken (1)
- layered soil (1)
- risk, reliability, inspection planning, offshore wind turbines (1)
- structural health monitoring (1)
- structural integrity management (1)
- support structures (1)
- temperature (1)
- transmission behavior (1)
- zerstreute Achslastimpulse (1)
- Übertragungsmatrizen (1)
- Übertragungsverhalten (1)
- Überwachung (1)
Organisationseinheit der BAM
Paper des Monats
- ja (5)
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.
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.
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.
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.
Nowadays geotechnical engineering firms have powerful software tools to extent their consult-ing 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 par-ticularly 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 re-quirements 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 guid-ance has been published in the past. A machine foundation on a homogeneous half space ex-cited by harmonic loads with excitation frequency between 4 Hz and 64 Hz has been ana-lysed 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.
Am Beispiel von mehreren Bauvorhaben wird untersucht, mit welchen Unsicherheiten bei der Anwendung von Korrelationen zwischen Sondierergebnissen und Scherwellengeschwindigkeit zur Beschreibung der dynamischen Bodeneigenschaften gerechnet werden muss. Die Auswertung von Korrelationen aus der Literatur zur Abschätzung der Scherwellengeschwindigkeit aus Drucksondierdaten zeigt, dass bei homogenen Sandböden die Verteilung der Scherwellengeschwindigkeit über die Tiefe sehr gut wiedergegeben werden kann. Die Korrelationen haben dabei die Tendenz, den tatsächlichen Wert zu überschätzen. In den vorliegenden Fällen haben sich Überschätzungen zwischen 20 % und 50 % ergeben. Mit zunehmendem Feinkornanteil werden die Unsicherheiten aus den Korrelationen jedoch größer.
Die natürliche Variabilität des Bodens bewirkt, dass jegliche in-situ Messung dynamischer Bodenparameter stets nur den Untersuchungsort beschreiben, und jede Verwendung für benachbarte Orte bereits eine Extrapolation ist. Gleichzeitig ist die Ermittlung von Bodeneigenschaften in-situ mit erheblichen Kosten verbunden, insbesondere bei Standorten wie z. B. Offshore-Windparks. Im innerstädtischen Raum sind seismische Messungen wegen der vorhandenen Bebauung und Flächenversiegelungen nur eingeschränkt möglich. Es bietet sich daher an, indirekte Methoden auf Basis von Drucksondierungen anzuwenden, weil diese Untersuchungen inzwischen zum Standardrepertoire selbst bei kleineren Bauvorhaben gehören.
Der neue nationale Anhang zu DIN EN 1998-1 erlaubt die Anwendung von Korrelationen zwischen Sondierergebnissen und dynamischen Bodeneigenschaften zur Anwendung bei seismischen Standortanalysen. Es werden jedoch keine Hinweise zur Auswahl geeigneter Korrelationen gegeben. Mit ISO/TS 14837-32 liegt ein Standard vor, in dem sogar für sandartigen Boden und tonartigen Boden zwei konkrete Korrelationen zur Anwendung vorgeschlagen werden. Dasselbe gilt für den Entwurf des Eurocode 7-2, prEN 1997-2 von 2022.
Untersuchungen zeigen, dass seismische Verfahren, wenn sie nicht unter Labor-Freifeldbedingungen durchgeführt werden, signifikante Streuungen aufweisen. Sofern statistische Korrelationen eine Streuung aufweisen, die in derselben Größenordnung liegen wie Ergebnisse seismischer Verfahren, können beide Verfahren in Grundsatz alternativ eingesetzt werden.
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.
ISO 14837-32:2015 and DIN EN 1998-1/NA:2021 as well as prEN 1997-2:2022 allow for us-ing 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 applica-bility 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 conse-quently 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.
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.
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.
The current practice of operating and maintaining deteriorating structural systems ensures acceptable levels of structural reliability, but it is not clear how efficient it is. Changing the current prescriptive approach to a risk-based approach has great potential to enable a more efficient management of such systems. Risk-based optimization of operation and maintenance strategies identifies the strategy that optimally balances the cost for controlling deterioration in a structural system with the achieved risk reduction. Inspections and monitoring are essential parts of operation and maintenance strategies. They are typically performed to reduce the uncertainty in the structural condition and inform decisions on future operation and maintenance actions. In risk-based optimization of operation and maintenance strategies, Bayesian updating is used to include information contained in inspection and monitoring data in the prediction of the structural reliability. All computations need to be repeated many times for different potential inspection and monitoring outcomes. This motivates the development of robust and efficient approaches to this computationally challenging task.
The reliability of deteriorating structural systems is time-variant because the loads on them and their capacities change with time. In most practical applications, the reliability analysis of deteriorating structural systems can be approached by dividing their lifetime into discrete time intervals. The time-variant reliability problem can then be represented by a series of time-invariant reliability problems. Using this methodology as a starting point, this thesis proposes a novel approach to compute the time-variant reliability of deteriorating structural systems for which inspection and monitoring data are available. The problem is formulated in a nested way in which the prediction of the structural condition is separated from the computation of the structural reliability conditional on the structural condition. Information on the structural condition provided by inspections and monitoring is included in the reliability assessment through Bayesian updating of the system deterioration model employed to predict the structural condition. The updated system reliability is obtained by coupling the updated deterioration model with a probabilistic structural model utilized to calculate the failure probability conditional on the structural condition. This approach is the first main outcome of this thesis and termed nested reliability analysis (NRA) approach. It is demonstrated in two numerical examples considering inspected and monitored steel structures subject to high-cycle fatigue.
An alternative – recently developed – approach, which also follows the strategy of discretizing time, describes deteriorating structural systems with hierarchical dynamic Bayesian networks (DBN). DBN combined with approximate or exact inference algorithms also enable the computation of the time-variant reliability of deteriorating structural systems conditional on information provided by inspection and monitoring data. In this thesis – as a proof of concept – a software prototype is developed based on the DBN approach, which can be used to assess the reliability of a corroding concrete box girder for which half-cell potential measurements are available. This is the second main outcome of this thesis.
Both approaches presented in this thesis enable an integral reliability analysis of inspected and monitored structures that accounts for system effects arising from (a) the correlation among deterioration states of different structural elements, (b) the interaction between element deterioration and system failure, and (c) the indirect information gained on the condition of all unobserved structural elements from inspecting or monitoring the condition of some structural elements. Thus, both approaches enable a systemwide risk-based optimization of operation and maintenance strategies for deteriorating structural systems.
The NRA approach can be implemented relatively easily with subset simulation, which is a sequential Monte Carlo method suitable for estimating rare event probabilities. Subset simulation is robust and considerably more efficient than crude Monte Carlo simulation. It is, however, still sampling-based and its efficiency is thus a function of the number of inspection and monitoring outcomes, as well as the value of the simulated event probabilities. The current implementation of the NRA approach performs separate subset simulation runs to estimate the reliability at different points in time. The efficiency of the NRA approach with subset simulation can be significantly improved by exploiting the fact that failure events in different years are nested. The lifetime reliability of deteriorating structural systems can thus be computed in reverse chronological order in a single subset simulation run.
The implementation of the DBN approach is much more demanding than the implementation of the NRA approach but it has two main advantages. Firstly, the graphical format of the DBN facilitates the presentation of the model and the underlying assumptions to stakeholders who are not experts in reliability analysis. Secondly, it can be combined with exact inference algorithms. In this case, its efficiency neither depends on the number of inspection and monitoring outcomes, nor on the value of the event probabilities to be calculated. However, in contrast to the NRA approach with subset simulation, the DBN approach with exact inference imposes restrictions on the number of random variables and the dependence structure that can be implemented in the 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.
Brücken werden durch Inspektionen und teilweise durch Monitoring überwacht, um Daten und Informationen über den Zustand und die Einwirkungen zu sammeln. Auf deren Grundlage werden Entscheidungen hinsichtlich Maßnahmen zur Gewährleistung der Sicherheit und Verfügbarkeit getroffen. In diesem Vortrag werden die Potentiale der Digitalisierung zur Unterstützung und Verbesserung der Brückenüberwachung diskutiert. Insbesondere werden die Bereiche Datenmanagement, Brückenmodellierung und Entscheidungsfindung betrachtet.
In this presentation, we discuss the potential of probabilistic approaches to the design and assessment of offshore foundations. The potential is demonstrated in a numerical example considering a laterally loaded monopile. As an outlook, we present a concept for managing the risk associated with installing large monopiles.
In this presentation, a framework for integrating vibration-based structural health monitoring data into the optimization of inspection and maintenance of deteriorating structural systems is presented. The framework is demonstrated in an illustrative example considering a steel frame subject to fatigue.
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.
In this contribution, we consider two applications in which probabilistic approaches can potentially complement or enhance the design and assessment of offshore wind turbine foundations. First, we illustrate in a numerical example that probabilistic modelling can be helpful in dealing with chang-es in turbine locations during the planning phase of an offshore wind farm. In this case, spatial probabilistic modelling of the ground conditions enables (a) an inference of the soil properties at the modified turbine location from field data collected at different locations across an offshore wind farm site and (b) an optimisation of further site investigations. Second, we discuss the uncer-tainties and risks associated with the installation of large diameter monopiles in soils with hetero-geneities such as strong layers and/or embedded boulders. Subsequently, we present a concept for modelling, understanding, and managing these risks based on a probabilistic model of the subgrade conditions, monopile, and subgrade-pile-interaction.
Monitoringsysteme erfassen kontinuierlich Bauwerksdaten wie z.B. Bauwerksbeschleunigungen, auf deren Grundlage Bauwerksschäden mit Hilfe von SHM-Methoden quantifiziert werden können. Mit den gewonnenen Informationen über den aktuellen Bauwerkszustand können Vorhersagen des Bauwerkszustandes und der Bauwerkszuverlässigkeit aktualisiert und erforderliche Inspektionen und Instandhaltungsmaßnahmen vorausschauend geplant werden. Im BMBF-Forschungsvorhaben AISTEC entwickeln der Fachbereich 7.2 „Ingenieurbau“ innovative Monitoringverfahren zur Systemidentifikation und automatischen Detektion, Lokalisierung und Quantifizierung von Schäden an Infrastrukturbauwerken anhand von gemessenen dynamischen und statischen Bauwerksdaten. Im Rahmen dieses Projektes werden die Verfahren an der Maintalbrücke bei Gemünden angewendet, welche Teil der ICE-Strecke Hannover-Würzburg ist. In diesem Vortrag wird das für die Maintalbrücke Gemünden geplante und umgesetzte Monitoingsystem vorgestellt.
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.
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.
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.
Bei Monopfahlgründungen von Offshore-Windenergieanlagen wird die Verbindung zwischen Monopfahl und Übergangsstück als geschraubter Ringflansch ausgeführt. Die zunehmende Leistungsfähigkeit der Windenergieanlagen führt zu immer größeren Schnittgrößen in diesem Anschluss. In der Folge erhöhen sich nicht nur die Querschnittsabmessungen, sondern es kommen auch zunehmend größere Schrauben zum Einsatz. Da die einschlägigen Regelwerke zur Bemessung dieser Verbindungen nicht für Schrauben der Größen M64 oder M72 konzipiert wurden, stellt sich die Frage der Übertragbarkeit auf solche Anwendungsfälle.
Im Rahmen des Aufsatzes werden Einflüsse diskutiert, die eine Herabsetzung der Schraubentragfähigkeit verursachen könnten. Diese Einflüsse, vornehmlich geometrische Imperfektionen, werden systematisch untersucht und ergänzend in praxisrelevanten Beispielen bewertet. Die somit gewonnenen Erkenntnisse werden für die abschließende Beurteilung der großen Schrauben in Ringflanschverbindungen herangezogen.
Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced.
Remediation of Cracks Formed in Grouted Connections of Offshore Energy Structures under Static Loads
(2018)
The future energy demand necessitates the exploration of all potential energy sources both onshore and offshore. Global trend has shifted towards offshore energy, which can be obtained from either carbon intensive or renewable options, hence requiring structures such as rigs, platforms, and monopiles. Most of these structures adopt easily installable construction techniques, where lower foundation need to be connected with the super structure by mean of grouted composite joints. Generally, these composite connections have exterior sleeve, interior pile and infill grout. Being located in remote offshore conditions, connections can experience considerable adverse loading during their lifetimes. Degradations were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites may often be proven difficult, which eventually leads to reduced capacity of connections in the long run. Thus, repair and rehabilitation of such connections should be planned ahead to minimize operational delays and costs in the future. This study aims at characterizing the nature of crack generation in grouted connections and thereby identifying the potential of repair using suitable repair material. Scaled grouted joints were manufactured using a novel mold, and connections were loaded under static load to visualize the main failure pattern. The failure mechanism and loading capacity are found compatible to previous results from earlier literature. Grouted connection was then repaired using cementitious injectable grout. The effectiveness of the repair system is also discussed.
Superplasticizer and shrinkage reducing admixture dosages for microfine cement in grout systems
(2018)
Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system.
Repair is an indispensable part of the maintenance of structures over their lifetimes. Structural grouting is a widely used remediation technique for concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. A structural grout system should be injectable in narrow spaces and hence include ingredients with finer particles. Ultrafine cements are ideal for these type of demanding grouts due to their superior properties compared to that of the less expensive, but coarser ordinary Portland cement (OPC). Supplementary cementitious materials (SCMs) are often used to replace OPC clinker based binder in order to modify certain properties and to reduce costs. The most commonly used SCMs are fly ash (FA), and ground granulated blast furnace slag (GGBS). For various special applications microsilica (MS), and metakaolin (MK) are also used. Identifying the optimum replacement contents of OPC by SCMs are a challenge during the design of such grouts. The aim of this experimental study is to investigate the effect of the selected SCMs (FA, MS and MK) on the slump flow, time of efflux, viscosity, shrinkage, and compressive and flexural strength of ultrafine cement based grouts with constant water-binder ratio and superplasticizer content. The test program was formulated using Box-Behnken design principles. Maximum percentages of replacement with ultrafine cement was 6% by volume of cement for MS and 16% for FA, and MK. The results suggest that most investigated grouts have the potential to be used for structural applications. The appropriate quadratic models are then formulated through statistical tools and presented as response surfaces. The trends indicate that fly ash improves the rheological properties, whereas microsilica and metakaolin positively affect shrinkage and mechanical properties to some extent. Based on the influence of SCMs and priorities among the properties, Decision Matrix Analysis (DMA) is carried out to select the most suitable ones among the SCMs. The analysis suggests that microsilica and fly ash are more suitable as SCMs than metakaolin without affecting the properties.
Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems
(2019)
Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system.
Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced.
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.
Remediation of Cracks Formed in Grouted Connections of Offshore Energy Structures under Static Loads
(2018)
The future energy demand necessitates the exploration of all potential energy sources both onshore and offshore. Global trend has shifted towards offshore energy, which can be obtained from either carbon intensive or renewable options, hence requiring structures such as rigs, platforms, and monopiles. Most of these structures adopt easily installable construction techniques, where lower foundation need to be connected with the super structure by mean of grouted composite joints. Generally, these composite connections have exterior sleeve, interior pile and infill grout. Being located in remote offshore conditions, connections can experience considerable adverse loading during their lifetimes. Degradations were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites may often be proven difficult, which eventually leads to reduced capacity of connections in the long run. Thus, repair and rehabilitation of such connections should be planned ahead to minimize operational delays and costs in the future. This study aims at characterizing the nature of crack generation in grouted connections and thereby identifying the potential of repair using suitable repair material. Scaled grouted joints were manufactured using a novel mold, and connections were loaded under static load to visualize the main failure pattern. The failure mechanism and loading capacity are found compatible to previous results from earlier literature. Grouted connection was then repaired using cementitious injectable grout. The effectiveness of the repair system is also discussed.
Impact resistance of reinforced concrete (RC) structures can be significantly improved by strengthening RC members with thin composite layers featuring high damage tolerance. Indeed, to limit the well-known vulnerability of cement-based materials against impact loading, the synergistic effects of short fibres and continuous textile meshes as hybrid reinforcement has been proved to be highly beneficial. This paper addresses the characterisation of novel cement-based hybrid composites through accelerated drop-weight impact tests conducted on rectangular plates at different impact energies. Two distinct matrices are assessed, with particular interest in a newly developed limestone calcined clay cement (LC3)-based formulation. Important parameters quantifying energy dissipation capability, load bearing capacity and damage are cross-checked to compute the ballistic limit and estimate the safety-relevant characteristics of the different composites at hand. Although textiles alone can improve the damage tolerance of fine concrete to some extent, the crack-bridging attitude of short, well-dispersed fibres in hybrid composites imparts a certain ductility to the cement-based matrices, allowing a greater portion of the textile to be activated and significantly reducing the amount of matrix spalling under impact.
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.
Inspection and maintenance contribute significantly to the lifetime cost of bridges. There is significant potential in using information obtained through structural health monitoring to update predictive models of the condition and performance of such structures, and thus ena-ble an improved decision-making regarding inspection and maintenance activities. Within the AISTEC project funded by the German Federal Ministry of Education and Research, we develop vibration-based structural health monitoring systems aimed at continuously provid-ing information on the structural condition of bridges. Environmental variations such as changing ambient temperatures can significantly influence the dynamic characteristics of bridges and thus mask the effect of structural changes and damages. It remains a challenge to account for such influences in structural health monitoring. To study the effect of ambient temperatures on the dynamic characteristics of beam structures, we monitor the vibration response of a reinforced concrete beam in the uncracked and cracked state at varying tem-peratures in a climate chamber. We postulate a set of competing parameterized probabilistic structural models, which explicitly account for the effect of varying ambient temperatures on the mechanical properties of the system. We then combine the information provided by the structural models with the information contained in the recorded vibration data to learn the parameters of the temperature-dependent structural models and infer the plausible state of the beam using Bayesian system identification and model class selection.
Brücken sind Teil der alternden Verkehrsinfrastruktur. Um die Nutzungsdauer zu verlängern und plötzliche Schäden zu detektieren kann Bauwerksmonitoring ("Structural Health Monitoring") eingesetzt werden. Der Einfluss von Umgebungsbedingungen, beispielsweise der Temperatur, auf das Bauwerksverhalten ist meist größer als der Einfluss von Schäden. Diese Einflüsse bestmöglich voneinander zu trennen und Veränderungen im Tragverhalten korrekt Schäden oder Umgebungsbedingungen zuzuordnen ist eine offene Forschungsfrage. Diese Arbeit zeigt eine mögliche Lösung, bei der gekoppelte Modelle von Umwelteinflüssen, Schäden und Tragverhalten des Bauwerks auf Grundlage von Monitoringdaten aktualisiert werden. Das Framework dazu wird vorgestellt und an einem Laborexperiment eines Stahlbetonbalkens in der Klimakammer angewandt. Die Ergebnisse bestätigen die Vorgehensweise. In nächsten Schritten müssen komplexere Tragwerke und die Sensitivität des Ansatzes untersucht werden.
Structural health monitoring (SHM) intends to improve the management of engineering structures. The number of successful SHM projects – especially SHM research projects – is ever growing, yielding added value and more scientific insight into the management of infrastructure asset. With the advent of the data age, the value of accessible data becomes increasingly evident. In SHM, many new data-centric methods are currently being developed at a high pace. A consequent application of research data management (RDM) concepts in SHM projects enables a systematic management of raw and processed data, and thus facilitates the development and application of artificial intelligence (AI) and machine learning (ML) methods to the SHM data. In this contribution, a case study based on an institutional RDM framework is presented. Data and metadata from monitoring the structural health of the Maintalbrücke Gemünden for a period of 16 months are managed with the RDM system BAM Data Store, which makes use of the openBIS data management software. An ML procedure is used to classify the data. Feature engineering, feature training and resulting data
are performed and modelled in the RDM system.