7.2 Ingenieurbau
Filtern
Dokumenttyp
- Zeitschriftenartikel (45)
- Beitrag zu einem Tagungsband (15)
- Buchkapitel (2)
Referierte Publikation
- ja (62) (entfernen)
Schlagworte
- Compressive strength (4)
- Structural health monitoring (4)
- Train passage (4)
- Damage detection (3)
- Fatigue (3)
- Hammer impact (3)
- Reliability (3)
- Slab track (3)
- Statistical tests (3)
- Structural Health Monitoring (3)
- Axle impulses (2)
- Axle sequence (2)
- Bauwerksüberwachung (2)
- Bridge (2)
- Brücken (2)
- Earth block masonry (2)
- Ground vibration (2)
- Irregular soil (2)
- Model interpolation (2)
- Moisture content (2)
- Offshore (2)
- Relative humidity (2)
- Resonance (2)
- Soil erosion (2)
- Static axle loads (2)
- Structural systems (2)
- Subspace-based method (2)
- Train-induced ground vibration (2)
- Vehicle–track interaction (2)
- Wind turbine tower (2)
- Achsfolgespektren (1)
- Acoustic emission (1)
- Acoustic emission analysis (1)
- Ambient excitation (1)
- Ansys Autodyn (1)
- Artificial Intelligence (1)
- Attenuation (1)
- Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases (1)
- Automated operational modal analysis (1)
- Autonomous underwater vehicles (1)
- Ballast track (1)
- Bauteile (1)
- Bauwerke (1)
- Bauwerksdiagnostik (1)
- Bauwerksmonitoring (1)
- Bayesian analysis (1)
- Bayesian system identification (1)
- Belastungstest (1)
- Benchmark (1)
- Boundary element (1)
- Box-Behnken (1)
- Bridge resonance (1)
- Bridge vibration (1)
- Buckling soil-structure-interaction offshore piles track (1)
- Building and Construction (1)
- Cancellation (1)
- Cement-based composites (1)
- Civil and Structural Engineering (1)
- Coating (1)
- Cohesive granular materials (1)
- Compaction grouting (1)
- Compliance function (1)
- Compression tests (1)
- Computational (1)
- Computer Vision (1)
- Concrete (1)
- Condensed Matter Physics (1)
- Continuous soil (1)
- Continuously inhomogeneous geological media (1)
- Continuously inhomogeneous soils (1)
- Crack Luminescence (1)
- Crack damage detection (1)
- Cracks (1)
- Cyber security (1)
- DUCON® (1)
- Damage characterization (1)
- Damage evolution (1)
- Damage identification (1)
- Damage localization (1)
- Decision matrix analysis (1)
- Deterioration (1)
- Digital Image Correlation (DIC) (1)
- Digitalisierung (1)
- Discrete Element Method (1)
- Discrete element method (1)
- Drucker-Prager (1)
- Ductility (1)
- Dynamic axle loads (1)
- E-modulus (1)
- Earth blocks (1)
- Earth masonry (1)
- Elastische Gebäudelagerung (1)
- Environmental changes (1)
- Environmental effects (1)
- Ermüdung (1)
- Erosion (1)
- Estimation (1)
- Fatigue strength (1)
- Fault detection (1)
- Fault detectionchanging (1)
- Features (1)
- Fequency domain (1)
- Fibre optic sensors (1)
- Filter effects (1)
- Finite element (1)
- Finite element analysis (1)
- Finite elements (1)
- Finite-element boundary-element method (1)
- Fly ash (1)
- GPA (1)
- GPU Parallel computing (1)
- General Materials Science (1)
- Geology (1)
- Geometric vehicle and track irregularities (1)
- Granular cohesion (1)
- Grout (1)
- Grouted connection (1)
- Grouting (1)
- HAZID (1)
- High-rise building (1)
- Horizontal wind turbine (1)
- Hydraulic jet erosion (1)
- Impact (1)
- Impact loading (1)
- Imperfektion (1)
- Impinging jet (1)
- Inclination angle (1)
- Inspection (1)
- Inspection planning (1)
- Interface (1)
- Irregular ballast (1)
- Jacket support structure (1)
- Jet erosion test (1)
- Jet impingement (1)
- LBM-DEM (1)
- Laminar flow (1)
- Large components (1)
- Lateral dynamic displacement (1)
- Lattice Boltzmann Method (1)
- Lattice Boltzmann method (1)
- Layered soil (1)
- Layered soils (1)
- Linear parameter varying systems (1)
- Load identification (1)
- Load tests (1)
- Load vector (1)
- Load-bearing behaviour (1)
- Local approaches (1)
- Luminescence (1)
- Material Point Method (MPM) (1)
- Merkblatt (1)
- Metakaolin (1)
- Micro-reinforcement (1)
- Microfine Cement (1)
- Micromechanical modelling (1)
- Microsilica (1)
- Mitigation (1)
- Mix design (1)
- Mixed formulation (1)
- Mobile elements (1)
- Modal analysis (1)
- Modalanalyse (1)
- Model update (1)
- Model updating (1)
- Modell-Update (1)
- Modulus of elasticity (1)
- Moisture (1)
- Monitoring (1)
- Monitoring-informed inspection and maintenance planning (1)
- Multi-beam track model (1)
- Non-Destructive Evaluation (1)
- Numerical modeling (1)
- Obstacles (1)
- Offshore geomechanics (1)
- Offshore pile foundation (1)
- Offshore steel structures (1)
- Offshore wind turbine (1)
- Optimal sensor placement (1)
- Perfectly Matched Layer (PML) (1)
- Piaui state (1)
- Pile bending stiffness (1)
- Pile foundation (1)
- Planar tomography (1)
- Post-impact evaluation (1)
- Pressure (1)
- Probability of Detection (1)
- Process noise (1)
- Quasi-static and dynamic tests (1)
- Quasi-static response; (1)
- Rail roughness (1)
- Railway (1)
- Railway bridge (1)
- Random dynamics and vibrations (1)
- Random stiffness variation (1)
- Randomly heterogeneous soil (1)
- Rechenmodelle (1)
- Recovery experiments (1)
- Rehabilitation (1)
- Reinforced concrete structure (1)
- Remote sensing vibrometer (1)
- Repair (1)
- Residual evaluation (1)
- Richtlinie (1)
- Risk (1)
- Risk-based design (1)
- SHCC (1)
- SHM (1)
- SHM environmental bridges (1)
- Safety (1)
- Sandstone (1)
- Santa-marta (1)
- Scattered axle impulses (1)
- Scattering (1)
- Schrauben (1)
- Serra da cangalha (1)
- Shell buckling (1)
- Shrinkage Reducing Admixture (1)
- Soil forces (1)
- Soil stiffness (1)
- Soil-structure interaction (1)
- Sorption isotherm (1)
- Static loading (1)
- Statistical evaluation (1)
- Statistical method (1)
- Statistical pattern recognition (1)
- Stereo photogrammetry (1)
- Stiffness variation (1)
- Strain (1)
- Strength (1)
- Stress-strain relation (1)
- Stress–strain-relation (1)
- Structural system identification (1)
- Strukturmonitoring (1)
- Subspace methods (1)
- Subspace-based residual (1)
- Superplasticizer (1)
- Supplementary Cementitious Materials (1)
- Sustainable binders (1)
- System identification (1)
- TRC (1)
- Temperature effect (1)
- Temperature effect rejection (1)
- Temperature modeling (1)
- Temperature rejection (1)
- Track deflection (1)
- Track displacements (1)
- Track filter (1)
- Track filtering (1)
- Track-soil interaction (1)
- Train-induced vibration (1)
- Transverse butt weld (1)
- Trench (1)
- Tunnel (1)
- Tunnel-to-surface reduction (1)
- UAS (1)
- UHPC (1)
- Ultrasonic testing (1)
- Unbounded domain (1)
- Uncertainty (1)
- Uncertainty in reference (1)
- Uncertainty quantification (1)
- Value of information (1)
- Variational Bayesian statistics (1)
- Vehicle-track interaction (1)
- Vibration measurement (1)
- Vibration measurements (1)
- Vibrations (1)
- Viscosity (1)
- Vorspannung (1)
- Water Science and Technology (1)
- Wavenumber domain (1)
- Weld imperfections (1)
- Wheelset (1)
- Wind (1)
- Wind energy (1)
- Wind energy tower (1)
- Windenergieanlage (1)
- Windenergieanlagen (1)
- Workability (1)
- layered soil (1)
- temperature (1)
Organisationseinheit der BAM
- 7.2 Ingenieurbau (62) (entfernen)
Paper des Monats
- ja (5)
This article deals with the relevance and practical feasibility of micromechanical simulations for their application to general geomechanical problems involving fluid-saturated granular assemblies, whether frictional or cohesive. A set of conceptual and numerical tools is here presented, advocating for a parallel computation using graphical processing units (GPUs) to treat large numbers of degrees of freedom with conventional Desktop computers. The fluid phase is here simulated with a particle-resolved approach in the frame of the Lattice Botzmann Method (LBM) while the granular solid phase is modelled as a collection of discrete particles from a Molecular Dynamics DEM perspective. The range of possible material behaviours for the solid granular phase is intended here to cover a broad spectrum from purely frictional to viscous cohesive materials with either brittle or transient debonding features. Specific details of the implementation and some validation cases are put forward.
Finally, some exemplary applications in the fields of soil erosion and geotechnical profile installation are provided along with a discussion on the parallel performance of the presented models. The results show that a micromechanical approach can be feasible and useful in practice, providing meaningful insights into complex engineering problems like the erosion kinetics of a soil under an impinging jet or the penetration resistance of a deep foundation in a layered soil profile.
Cerro do Jarau is a conspicuous, circular morpho‐structural feature in Rio Grande do Sul State (Brazil), with a central elevated core in the otherwise flat “Pampas” terrain typical for the border regions between Brazil and Uruguay. The structure has a diameter of approximately 13.5 km. It is centered at 30o12′S and 56o32′W and was formed on basaltic flows of the Cretaceous Serra Geral Formation, which is part of the Paraná‐Etendeka Large Igneous Province (LIP), and in sandstones of the Botucatu and Guará formations. The structure was first spotted on aerial photographs in the 1960s. Ever since, its origin has been debated, sometimes in terms of an endogenous (igneous) origin, sometimes as the result of an exogenous (meteorite impact) event. In recent years, a number of studies have been conducted in order to investigate its nature and origin. Although the results have indicated a possible impact origin, no conclusive evidence could be produced. The interpretation of an impact origin was mostly based on the morphological characteristics of the structure; geophysical data; as well as the occurrence of different breccia types; extensive deformation/silicification of the rocks within the structure, in particular the sandstones; and also on the widespread occurrence of low‐pressure deformation features, including some planar fractures (PFs). A detailed optical microscopic analysis of samples collected during a number of field campaigns since 2007 resulted in the disclosure of a large number of quartz grains from sandstone and monomict arenite breccia from the central part of the structure with PFs and feather features (FFs), as well as a number of quartz grains exhibiting planar deformation features (PDFs). While most of these latter grains only carry a single set of PDFs, we have observed several with two sets, and one grain with three sets of PDFs. Consequently, we here propose Cerro do Jarau as the seventh confirmed impact structure in Brazil. Cerro do Jarau, together with Vargeão Dome (Santa Catalina state) and Vista Alegre (Paraná State), is one of very few impact structures on Earth formed in basaltic rocks.
The surface erosion of soil samples caused by an impinging jet can be analyzed using the jet erosion test (JET), a standard experimental test to characterize the erosion resistance of soils. This paper specifically addresses the flow characteristics of a laminar impinging jet over the irregular surface of granular beds to discuss the pertinence and relevance of commonly used empirical estimations based on a selfsimilar model of a free jet. The JET is here investigated at the microscale with a coupled fluid-particle flow numerical odel featuring the lattice Boltzmann method (LBM) for the fluid phase combined with the discrete element method (DEM) for the mechanical behavior of the solid particles. The hydrodynamics of a laminar plane free jet are confronted with the results from a parametric study of jet impingement, both on solid smooth and fixed granular surfaces, that take into account variations in particle size, distance from jet origin, and jet Reynolds number. The flow characteristics at the bed surface are here quantified, including the maximal values in tangential velocity and wall shear stress, which can be regarded as the major cause of particle detachments under hydrodynamic solicitation. It is shown that the maximal velocity at the impinged surface can be described by the free jet self-similar model, provided that a simple empirical coefficient is introduced. Further, an expression is proposed for the maximal shear stress in laminar conditions, including a Blasius-like friction coefficient that is inversely proportional to the square root of the jet Reynolds number. To conclude, finally, the JET erosion of different cohesionless granular samples is analyzed, confirming that the threshold condition at the onset of granular motion is consistent with the Shields diagram and in close agreement with previous experimental results.
Environmental based perturbations influence significantly the ability to identify structural dam-age in Structural Health Monitoring. Strategies are needed to classify such effects and consider them appropri-ately in SHM. It has to be considered if seasonal effects just mask the structural response or if temperature itself correlates to a weakening of the structure. 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 considering environmental as well as damage-based changes of stiffness values. With the background of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of proce-dures, separating environmental from damage caused changes in SHM measures. The contribution describes an attempt to evaluate both general strategies, their advantages and drawbacks. In addition, two vibration moni-toring procedures are introduced, allowing for temperature-based perturbations of the monitoring data.
The stability and geometric nonlinearities of slender structures are a major topic in structural design. While this topic is most relevant in the field of Structural Engineering, e.g. for steel or concrete structures, only few applications take the role of soil-structure-interaction explicitly into account. The focus of this paper is placed on the impact of soil support and its modelling for the buckling analysis based on examples both for pile foundations and for railway track stability. The general interaction between steel design and the geotechnical input will be addressed. The paper discusses and summarizes a range of subtopics based on experience and current research at the author’s institute.
Reliability analysis of deteriorating structural systems requires the solution of time-variant reliability problems.
In the general case, both the capacity of and the loads on the structure vary with time. This analysis can be approached by approximation through a series of time-invariant reliability problems, which is a potentially effective strategy for cases where direct solutions of the time-variant reliability problem are challenging, e.g. for structural systems with many elements or arbitrary load processes. In this contribution, we thoroughly Review the formulation of the equivalent time-invariant reliability problems and extend this approximation to structures for which inspection and monitoring data is available. Thereafter, we present methods for efficiently evaluating the reliability over time. In particular, we propose the combination of sampling-based methods with a FORM (first-order reliability method) approximation of the series system reliability problem that arises in the computation of the lifetime reliability. The framework and algorithms are demonstrated on a set of numerical examples, which include the computation of the reliability conditional on inspection data.
Damage detection and localization in civil or mechanical structures is a subject of active development and research. A few vibration‐based methods have been developed so far, requiring, for example, modal parameter estimates in the reference and damaged states of the investigated structure, and for localization in addition a finite element model. For structures in operation, temperature has been shown to be a major nuisance to the efficiency of such methods because the modal parameters are varying not only with damage but also due to temperature variations. For detection, a few rejection approaches have been developed. Besides the increased complexity, environmental variation is hardly taken into account in localization approaches. In this paper, we propose a sensitivity‐based correction of the identified modal parameters in the damaged state with respect to the temperature field in the reference state, on the basis of a sensitivity analysis with respect to temperature dependent Parameters of the finite element model in the reference state. The approach is then applied to the stochastic dynamic damage locating vector method, where its improved performance under nonuniform temperature variations is shown in a numerical application on a beam.
The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile-soil interface is subject to cyclic shearing solicitations. Thereby, the soil may densify and lead to a decrease of confining stress around the pile due to microphenomena such as particle crushing, migration and rearrangement. This reduction of radial stress has a direct impact on the shaft capacity, potentially leading in extreme cases to pile failure. An adequate interface model is needed in order to model this behaviour numerically. Different authors have proposed models that take typical Interface phenomena in account such as densification, grain breakage, normal pressure effect and roughness. However, as the models become more complex, a great number of material parameters need to be defined and calibrated. This paper proposes the adoption and transformation of an existing soil bulk model (Pastor- Zienkiewicz) into an interface model. To calibrate the new interface model, the results of an experimental campaign with the ring shear device under cyclic loading conditions are here presented. The constitutive model shows a good capability to reproduce typical features of sand behaviour such as cyclic compaction and dilatancy, which in saturated partially-drained conditions may lead to liquefaction and cyclic mobility phenomena.
Temperature variation can be a nuisance that perturbs vibration based structural health monitoring (SHM) approaches for civil engineering structures. In this paper, temperature affected vibration data is evaluated within a stochastic damage detection framework, which relies on a null space based residual. Besides two existing temperature rejection approaches – building a reference state from an averaging method or a piecewise method – a new approach is proposed, using model interpolation. In this approach, a general reference model is obtained from data in the reference state at several known reference temperatures. Then, for a particular tested temperature, a local reference model is derived from the general reference model. Thus, a well fitting reference null space for the formulation of a residual is available when new data is tested for damage detection at an arbitrary temperature. Particular attention is paid to the computation of the residual covariance, taking into account the uncertainty related to the null space matrix estimate. This improves the test performance, contrary to prior methods, for local and global damages, resulting in a higher probability of detection (PoD) for the new interpolation approach compared to previous approaches.
Within the presented research project, experimental and numerical investigations were performed to develop a thin-shelled, modular, mobile element system made of a micro-reinforced ultra-high-performance ductile concrete (DUCON®). Material parameters were experimentally determined to adapt the material model within the numerical analysis applying the Drucker-Prager relationship. Afterwards, for validation of the numerical models, quasi-static and high-velocity impact tests were performed on plate-like structures. Finally, a suitable geometry of transportable barrier elements will be designed, which provides a maximum of resistance against impact by a minimum of weight and a maximum of mobility.