7.2 Ingenieurbau
Filtern
Erscheinungsjahr
- 2018 (40) (entfernen)
Dokumenttyp
- Vortrag (20)
- Beitrag zu einem Tagungsband (10)
- Posterpräsentation (4)
- Zeitschriftenartikel (3)
- Buchkapitel (1)
- Beitrag zu einem Sammelband (1)
- Dissertation (1)
Sprache
- Englisch (40) (entfernen)
Schlagworte
- Repair (4)
- Box-Behnken (3)
- Fatigue (3)
- Grouting (3)
- Interface (3)
- Statistical tests (3)
- Acoustic emission testing (2)
- Amplitude-charge weight laws (2)
- Amplitude-distance laws (2)
- Analysis of variance (2)
- Compressive cyclic loading (2)
- Compressive strength (2)
- Cracks (2)
- DUCON® (2)
- Ductility (2)
- E-modulus (2)
- Energy (2)
- Explosion-induced ground vibrations (2)
- Fault detection (2)
- Grouted Connection (2)
- Hammer impact (2)
- High-strength concrete (2)
- Impact (2)
- Micro-reinforcement (2)
- Mix design (2)
- Mobile elements (2)
- Non-destructive testing (2)
- Numerical model (2)
- Numerical modeling (2)
- Numerical modelling (2)
- Offshore (2)
- Prediction of explosion induced ground and building vibration (2)
- Quasi-static and dynamic tests (2)
- Rehabilitation (2)
- Residual evaluation (2)
- SHM (2)
- Size effect (2)
- Slab track (2)
- Slenderness effect (2)
- Soil properties (2)
- Soil-structure interaction (2)
- Stereo photogrammetry (2)
- Structural health monitoring (2)
- Supplementary cementitious materials (2)
- Track damage (2)
- UHPC (2)
- Ultrasonic testing (2)
- Uncertainty in reference (2)
- Vibration measurements (2)
- 3D imaging (1)
- Ballast track (1)
- Beanspruchungszustand (1)
- Boundary element method (1)
- Bridge (1)
- Cohesive soils (1)
- Compaction Grouting (1)
- Compaction grouting (1)
- Conductor (1)
- Crack detection (1)
- Crack repair (1)
- Cyclic axial shearing (1)
- DEM-LBM simulation (1)
- Damage detection (1)
- Decision matrix analysis (1)
- Design (1)
- Design methods (1)
- Design practice (1)
- Digital Image Correlation (1)
- Digital Image Correlation (DIC) (1)
- Environmental (1)
- Environmental changes (1)
- Erosion (1)
- Erosion of cohesive soils (1)
- Features (1)
- Finite element model updating (1)
- Finite-Elemente-Modellkalibrierung (1)
- Fly ash (1)
- Freileitung (1)
- GPA (1)
- GPU parallelisation (1)
- Geology (1)
- Geomechanics (1)
- Geomechanics of offshore foundations (1)
- Ground vibration measurements (1)
- Grout (1)
- Grout Injection (1)
- HTLS (1)
- Inspection planning (1)
- Interface model (1)
- Jet erosion test (1)
- LBM-DEM simulation (1)
- Laminography (1)
- Load bearing behaviour (1)
- Material Point Method (1)
- Material Point Method (MPM) (1)
- Material model (1)
- Metakaolin (1)
- Microfine cement (1)
- Micromechanical LBM-DEM simulation (1)
- Microsilica (1)
- Mixed formulation (1)
- Offshore Pile Foundation (1)
- Offshore pile foundation (1)
- Offshore pile foundations (1)
- Offshore wind energy (1)
- Offshore wind farms (1)
- Optimierungsmethoden (1)
- Optimization techniques (1)
- Physical phenomenology (1)
- Piaui state (1)
- Pile Capacity (1)
- Pile foundations (1)
- Pressure (1)
- Recovery experiments (1)
- Reinforced concrete (1)
- Reliability (1)
- Risk (1)
- Sandstone (1)
- Santa-marta (1)
- Schwingungsmessungen (1)
- Serra da cangalha (1)
- Shearing (1)
- Shrinkage (1)
- Soil erosion (1)
- Soil-pile interaction (1)
- State of stress (1)
- Statistical pattern recognition (1)
- Steel structures (1)
- Strength (1)
- Subspace methods (1)
- Subspace-based method (1)
- TOP (1)
- Temperature effect (1)
- Track vibration (1)
- Train configuration (1)
- Train passage (1)
- Train passages (1)
- Tran speed (1)
- Truss structures (1)
- Vibration measurement (1)
- Vibrations (1)
- Viscosity (1)
- Wave-Tower interaction (1)
- Windfarm wake analysis (1)
- Workability (1)
- fachwerkartige Stahltragwerken (1)
- temperature (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (40) (entfernen)
Eingeladener Vortrag
- nein (20)
Measurements of ground and track vibrations have been performed at a high-speed line in northern Germany. Impacts on the track and the ground, and passages of different trains with different speeds on different tracks have been measured. Transfer functions of the soil are presented and approximated by theoretical soil models. By using these transfer functions, the measured ground vibration between 2 to 64 m distance from the track can be transformed into a load spectrum which can be used for predictions at other sites. The method is compared to the soil-dependent method of an emission spectrum at a certain distance (8 m for example). The influence of train type, speed and track type is discussed on the base of the different emission quantities and the original measurements. The strong influence of the track, ballast track and slab track, is analysed by a theoretical model in wavenumber domain. The response of the track to the passage of the static load is reduced by the stiffness of the slab, the deformation of the track as well as the impulse acting on the soil. Usually, the impulse on the soil should result in a slow quasi-static movement of the soil, slower at further distances. In a heterogeneous soil, however, the impulses from the static loads scatter and keep parts of the higher impulse frequency band. In this case the reduced impulse spectra of the slab track will yield reduced ground vibration in a certain frequency band. Additional (BAM and international) measurements will be used to discuss this and possible other explanations for the different ground vibration differences.
This contribution presents experimental methods to detect track damage. At BAM (Federal Institute of Material Research and Testing), a measuring car with a measuring system of 72 channels, geophones, mountings, cables, harmonic and impulsive exciters is used for dynamic measurements of the track, the soil and buildings. An instrumented hammer allows force measurements and to evaluate transfer functions of the track, and the soil. Wave measurements are used to identify the soil characteristics. Train passages are measured at the track and for the train induced ground vibrations. In addition to these in situ options, tests of tracks or track elements can be performed in a large laboratory.
Right from the beginning of applying SHM to bridge structures it was obvious that environmental based perturbations on the measurement significantly influence the ability to identify structural damage. Strategies are needed to classify such effects and consider them appropriately in SHM. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge taking into account environmental as well as damage based changes of stiffness values.
With the back-ground of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of procedures, separating environmental from damage caused changes in SHM measures. The contribution describes both general strategies and points out their Advantages and drawbacks. As basis, a review on relevant methods was conducted. The aim of the study is to classify approaches for separating damage describing information from environmental based perturbations in dependency of the SHM objective. And such, it is intended to describe a best practice in designing concepts for Monitoring infrastructure, naturally effected by environmental influences.
Right from the beginning of applying SHM to bridge structures it was obvious that environmental based perturbations on the measurement significantly influence the ability to identify structural damage.
Strategies are needed to classify such effects and consider them appropriately in SHM. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge taking into account environmental as well as damage based changes of stiffness values.
With the back-ground of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of procedures, separating environmental from damage caused changes in SHM measures. The contribution describes both general strategies and points out their Advantages and drawbacks. As basis, a review on relevant methods was conducted. The aim of the study is to classify approaches for separating damage describing information from environmental based perturbations in dependency of the SHM objective. And such, it is intended to describe a best practice in designing concepts for Monitoring infrastructure, naturally effected by environmental influences.
Surface erosion of a cohesive granular soil by a fluid flow is investigated numerically by coupling the Lattice Boltzmann Method (LBM) for the fluid phase and the Discrete Element Method (DEM) for describing the motion of the solid particles. In addition, inter-particles cohesion is insured by a contact model featuring a paraboloidal yield surface. The use of a fully resolved LBM-DEM coupling technique is currently limited due to the computational cost when simulating a large number of particles. This issue can be overcome using the graphics processing unit (GPU) thanks to ist massively parallel hardware architecture. Here, we first present a 2D GPU implementation of LBM-DEM coupling for a granular assembly. The GPU implementations are approximatively 30 times faster than a single core CPU version. Then, we apply the parallelization technique to practical erosional cases, namely the jet erosion test (JET) and the shear-driven erosion by a Couette flow. These numerical tests aim to relate micro parameters of a cohesive material (eg. cohesion) to macro parameters (eg. soil erodibility, mechanical strengths). Preliminary results show that micromechanical features indeed provide a novel insight of soil erosion phenomena.
The erosion phenomena is the main cause of the most serious incidents observed on earthen hydraulic structures such as dams and dikes. Thus, there is a real need to explore in depth and understand the mechanisms at work in such complex erosional processes for preventing similar risks.
The aim of this study is to provide a micromechanical insight into the mechanisms taking place during the erosion of a cohesive granular material driven by a fluid flow, the objectives are summarized as follows:
Perform numerical erosion tests.
Parallelization of the code (Gpu).
Extensive parametric analysis => rely micro parameters (eg. Cohesion) to macro parameters (eg. Soil erodibility, mechanical strengths).
Use of DEM-LBM modeling to prove the relevance of free jet model for soil erosion by impinging jet
(2018)
The aim of this study is to provide a micromechanical insight into the mechanisms taking place during the erosion of a cohesive granular material driven by a fluid flow, the objectives are summarized as follows:
Perform numerical erosion tests.
Parallelization of the code (Gpu).
Extensive parametric analysis => rely micro parameters (eg. Cohesion) to macro parameters (eg. Soil erodibility, mechanical strengths).
Design challenges for offshore wind-farms. From foundation mechanics to wind-farm aerodynamics
(2018)
This talk provides a brief introduction on general engineering aspects of offshore wind energy production. Then some geomechanical issues for the foundation of OWTs into the seabed are introduced, while the results from experimental investigations and coupled computational analysis are discussed.
In the second part of the seminar, the hydromechanical Wave–Tower interaction is firstly discussed. Then, some general aspects of the windfarm aerodynamics are introduced. On the one hand, some modelling possibilities for the wake analysis of single turbines and turbine groups are discussed. And on the other hand the relevance of such analyses for a proper windfarm layout optimization is pointed out.
Concerning the geomechanical issues the talk shows that: i) The pile’s bearing capacity can degrade under cyclic loading (waves, wind, …). ii) The time effects can be relevant: Capacity improvement can be substantial, but also fragile. iii) There are cyclic PWP effects: Cyclic interaction with pore water may lead to soil softening and an uncoupled analysis (current design practice) is potentially unsafe.
And concerning the hydromechanical and aerodynamical design considerations, this seminar shows that: i) Numerical analysis of turbine’s interaction with wind/waves is useful and affordable. ii) Simplified models can provide insight into windfarm aerodynamics. iii) Turbulent wake analysis is very relevant for the windfarm layout.
This presentation deals with the phenomenology and design of pile foundations for offshore wind turbines, and is divided in two lectures.
The first lecture presents a brief introduction to the context and peculiarities of such foundations, and then focuses on the particular case of axially loaded piles. This part is most relevant for the relatively slender piles of the multi-pile substructures (i.e. jackets and tripods). A clear distinction between physical phenomenology and practical design is drawn here.
The second lecture continues with the case of lateraly loaded offshore piles, which bears most relevance for the case of the monopile foundations. Here again, a clear separation between physical reality and design methods is intended.
Finally, the last part of the second lecture introduces several advanced topics which lie outside the classical design approaches, namely the cyclic pile fatigue and the so-called pile setup (i.e. the time effects on the axial pile capacity). The relevance of these two topics is illustrated with experimental results from a field testing campaign on real large-scale piles.