Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-58940 Vortrag Zinas, Orestis 3D Probabilistic Site Characterization The aim of the study is to infer the soil stratification from the provided CPT and borehole data. We infer the soil type at any location within the domain of interest from the SBT index Ic (Robertson, 2009). This index can be directly related to the CPT data through an empirical correlation model. In addition, the soil classes contained in the borehole logs can be expressed as bounds on Ic. A log-transformation was applied to Ic, Y = ln(Ic), and Y was modelled by a 3D Random Field, with a fully Bayesian hierarchical Gaussian Process model to explicitly capture uncertainties. 2023 19th eawe PhD Seminar Hannover, Germany 06.09.2023 08.09.2023 2023-11-28 OPUS4-59538 Vortrag Zinas, Orestis Potentials of probabilistic approaches in offshore foundation installation This presentation discusses the potentials of probabilistic methods in offshore foundation installation, from the perspective of probabilistic ground models and data-driven site characterization. We discuss about methodologies for utilizing site-specific geotechnical (CPT) and geological data, aiming to construct an integrated ground model that can predict stratigraphic profiles and useful for geotechnical design parameters at any location within a 3D domain. The predicted parameters and stratigraphy are then used to predict the probability of potential pile tip damage, upon collision with a boulder. 2024 Colloquium Buckling of Offshore Wind Energy Structures Berlin, Germany 14.02.2024 15.02.2024 2024-02-21 OPUS4-54949 Zeitschriftenartikel Wiehle, Philipp; Simon, Sebastian; Baier, J.; Dennin, L. Forde, M. Influence of relative humidity on the strength and stiffness of unstabilised earth blocks and earth masonry mortar Aim of this study is to provide information about moisture dependent material behaviour of unstabilised loadbearing earth blocks and mortars. Compressive strength and Young's modulus were investigated after conditioning in varying relative humidity reaching from 40 % up to 95 %. The material composition and physical properties were investigated to understand the influence of relative humidity onto the mechanical properties. A normalisation of strength and stiffness by the values obtained at 23 ◦C and 50 % relative humidity reveals a linear dependence of compressive strength and Young's modulus that is regardless of the material composition. Thus, it is possible to describe the influence of relative humidity onto the load-bearing behaviour of unstabilised earth masonry materials in a generally valid formulation. Elsevier Ltd. 2022 Construction and Building Materials 342 Part A 1 15 10.1016/j.conbuildmat.2022.128026 2022-06-08 OPUS4-56241 Zeitschriftenartikel Wiehle, Philipp; Brinkmann, M. Material behaviour of unstabilised earth block masonry and its components under compression at varying relative humidity block and mortar types is analysed with particular regard to the influence of varying relative humidity. The uniaxial compressive strength and deformation characteristics of unstabilised earth blocks and mortars as well as of unstabilised earth block masonry are studied in detail and compared to conventional masonry to evaluate whether the structural design can be made accordingly. An increase of 30 % points in relative humidity leads to a reduction of the masonry´s compressive strength between 33 % and 35 % whereas the Young´s modulus is reduced by 24-29 %. However, the ratio between the Young´s modulus and the characteristic compressive strength of earth block masonry ranges between E33/fk = 283-583 but is largely independent of the relative humidity. The results show that the mechanical properties of the investigated unstabilised earth block masonry are sufficient for load-bearing structures, yielding a masonry compressive strength between 2.3 MPa and 3.7 MPa throughout the range of moisture contents investigated. In general, the design concept of conventional masonry can be adapted for unstabilised earth masonry provided that the rather low Young´s modulus as well as the moisture dependence of both, compressive strength and Young´s modulus, are sufficiently taken into account. Netherlands Elsevier B.V. 2022 Case Studies in Construction Materials 17 1 15 urn:nbn:de:kobv:b43-562417 10.1016/j.cscm.2022.e01663 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2022-11-14 OPUS4-53231 Beitrag zu einem Tagungsband Wiehle, Philipp; Brinkmann, M. Tragfähigkeit von Lehmmauerwerk - Experimentelle und numerische Analyse Die Bemessung von tragendem Lehmmauerwerk erfolgt in Deutschland auf Basis der Lehmbau Regeln. Das dort verankerte Nachweisverfahren beruht auf einem globalen Sicherheitskonzept, welches aus zuverlässigkeitstheoretischer Sicht nicht mehr dem Stand der Technik entspricht. Auf Grund dessen wird das Bemessungskonzept für Lehmmauerwerk vom Deutschen Institut für Bautechnik (DIBt) voraussichtlich 2023 außer Kraft gesetzt. Ein statischer Nachweis von tragenden Lehmbauten wäre in Deutschland dann ausschließlich mit einer Zustimmung im Einzelfall (ZiE) oder vorhabenbezogener Bauartgenehmigung (vBg) möglich. Beides ist mit erheblichem Mehraufwand und höheren Kosten verbunden, was für den Lehmmauerwerksbau einen entscheidenden Nachteil im Vergleich zum konventionellen Mauerwerksbau darstellt. Um eine unkomplizierte Praxisanwendung von Lehmmauerwerk zu ermöglichen, werden innerhalb eines Forschungsvorhabens, welches von der Bundesanstalt für Materialforschung und -prüfung (BAM), dem Institut für Massivbau der Technischen Universität Darmstadt sowie dem Ingenieurbüro ZRS durchgeführt wird, auf Basis der Produktnormen für Lehmsteine und Lehmmauermörtel Grundlagen für ein aktualisiertes Bemessungskonzept entwickelt. Im Rahmen des Projekts wird ebenfalls untersucht, inwiefern die Bemessungsregeln nach den vereinfachten Berechnungsmethoden für unbewehrtes Mauerwerk gemäß DIN EN 1996-3 / NA auf den Lehmmauerwerksbau übertragbar sind. Falls eine Anwendung des normativen Nachweisverfahrens bei Lehmmauerwerk möglich ist, wäre zukünftig eine Aufnahme von Lehmsteinen und Lehmmauermörtel in den nationalen Anhang des Eurocode 6 denkbar, was eine bedeutsame Erweiterung des Anwendungsbereichs von Lehmmauerwerk zur Folge hätte. Diverse wissenschaftliche Untersuchungen konnten zeigen, dass bemessungsrelevante Festigkeits- und Verformungseigenschaften von Lehmmauerwerksbaustoffen stark von der vorherrschenden Materialfeuchte abhängen, welche im hygroskopischen Wassergehaltsbereich im Wesentlichen von der relativen Luftfeuchte (RLF) bestimmt wird. Auch die Zwischenergebnisse des laufenden Forschungsvorhabens zur Entwicklung eines Bemessungskonzepts für Lehmmauerwerk ergaben eine deutlich erkennbare Abhängigkeit zwischen der Materialfeuchte und den relevanten Festigkeits- und Verformungseigenschaften. Eine detaillierte Kenntnis des feuchteabhängigen Materialverhaltens von Lehmsteinen, -mörtel und -mauerwerk ist zwingend erforderlich, um ein konsistentes und zuverlässiges Bemessungskonzept für Lehmmauerwerk zu entwickeln. Im Rahmen des laufenden Forschungsprojektes werden deshalb umfangreiche Versuche zum Drucktragverhalten von Lehmsteinen und -mörtel sowie Lehmmauerwerk nach Konditionierung bei unterschiedlichen RLF durchgeführt und analysiert. Weiterhin werden auf Basis der experimentellen Ergebnisse numerische Modelle kalibriert, welche die detaillierte Analyse der Biegedrucktragfähigkeit von Lehmmauerwerk ermöglichen. In diesem Beitrag werden zunächst die bisherigen Zwischenergebnisse bezüglich der experimentell ermittelten feuchteabhängigen Materialkennwerte von Lehmsteinen, -mörtel und -mauerwerk dargelegt. Darauf aufbauend werden numerische Untersuchungen zur Bestimmung der Systemtragfähigkeit von Lehmmauerwerk unter Feuchteeinflusses durchgeführt und erläutert. Weimar Dachverband Lehm 2020 LEHM 2020 - Tagungsbeiträge der 8. Internationalen Fachtagung für Lehmbau LEHM 2020 Weimar, Germany 30.10.2020 01.11.2020 1 12 2021-09-16 OPUS4-48240 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Zhang, Q.; Hille, Falk; Mevel, L. Subspace-based Damage Detection with Rejection of the Temperature Effect and Uncertainty in the Reference 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. 2019 Proceedings of 8th International Operational Modal Analysis Conference International Operational Modal Analysis Conference Copenhagen, Danmark 13.05.2019 15.05.2019 1 11 2019-06-20 OPUS4-52999 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Simon, Patrick; Herrmann, Ralf; Hille, Falk; Mevel, L. Cunha, A.; Caetano, E. Stochastic subspace-based damage detection of a temperature affected beam structure Structural health monitoring (SHM) of civil structures often is limited due to changing environmental conditions, as those changes affect the structural dynamical properties in a similar way like damages can do. In this article, an approach for damage detection under changing temperatures is presentedand applied to a beam structure. The used stochastic subspace-based algorithm relies on a reference null space estimate, which is confronted to data from the testing state in a residual function. For damage detection the residual is evaluated by means of statistical hypothesis tests. Changes of the system due to temperature effects are handled with a model interpolation approach from linear parameter varying system theory. From vibration data measured in the undamaged state at some few reference temperatures, a model of the dynamic system valid for the current testing temperature is interpolated. The reference null space and the covariance matrix for the hypothesis test is computed from this interpolated model. This approach has been developed recently and was validated in an academic test case on simulations of a mass-spring-damper. In this paper, the approach is validated experimentally on a beam structure under varying temperature conditions in a climate chamber. Compared to other approaches, the interpolation approach leads to significantly less false positive alarms in the reference state when the structure is exposed to different temperatures, while faults can still be detected reliably. 2021 Proceedings of the 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10 Online meeting 30.06.2021 1 6 2021-07-26 OPUS4-52998 Zeitschriftenartikel Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Statistical subspace-based damage detection with estimated reference The statistical subspace-based damage detection technique has shown promising theoretical and practical results for vibration-based structural health monitoring. It evaluates a subspacebased residual function with efficient hypothesis testing tools, and has the ability of detecting small changes in chosen system parameters. In the residual function, a Hankel matrix of Output covariances estimated from test data is confronted to its left null space associated to a reference model. The hypothesis test takes into account the covariance of the residual for decision making. Ideally, the reference model is assumed to be perfectly known without any uncertainty, which is not a realistic assumption. In practice, the left null space is usually estimated from a reference data set to avoid model errors in the residual computation. Then, the associated uncertainties may be non-negligible, in particular when the available reference data is of limited length. In this paper, it is investigated how the statistical distribution of the residual is affected when the reference null space is estimated. The asymptotic residual distribution is derived, where its refined covariance term considers also the uncertainty related to the reference null space estimate. The associated damage detection test closes a theoretical gap for real-world applications and leads to increased robustness of the method in practice. The importance of including the estimation uncertainty of the reference null space is shown in a numerical study and on experimental data of a progressively damaged steel frame. Elsevier Ltd. 2022 Mechanical Systems and Signal Processing 164 108241 10.1016/j.ymssp.2021.108241 2021-07-26 OPUS4-51617 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Fault detection for linear parameter varying systems under changes in the process noise covariance Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models -- each estimated from data measured in a reference state -- are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. 2020 Preprints of the 21st IFAC World Congress (Virtual) IFAC World Congress 2020 Online meeting 11.07.2020 17.07.2020 13858 2020-11-23 OPUS4-52465 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Fault detection for linear parameter varying systems under changes in the process noise covariance Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models - each estimated from data measured in a reference state - are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. Elsevier 2020 IFAC-PapersOnLine: 21st IFAC World Congress 53 21st IFAC World Congress Online meeting 13.07.2020 2 13668 13673 urn:nbn:de:kobv:b43-524652 10.1016/j.ifacol.2020.12.868 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2021-04-21 OPUS4-46303 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Simani, S.; Patan, K. Asymptotic analysis of subspace-based data-driven residual for fault detection with uncertain reference The local asymptotic approach is promising for vibration-based fault diagnosis when associated to a subspace-based residual function and efficient hypothesis testing tools. It has the ability of detecting small changes in some chosen system parameters. In the residual function,the left null space of the observability matrix associated to a reference model is confronted to the Hankel matrix of output covariances estimated from test data. When this left null space is not perfectly known from a model, it should be replaced by an estimate from data to avoid model errors in the residual computation. In this paper, the asymptotic distribution of the resulting data-driven residual is analyzed and its covariance is estimated, which includes also the covariance related to the reference null space estimate. The advantages of the data-driven residual are demonstrated in a numerical study, and the importance of including the covariance of the reference null space estimate is shown, which increases the detection Performance. Elsevier International Federation of Automatic Control 2018 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2018 51 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2018 Warsaw, Poland 29.08.2018 31.08.2018 24 414 419 10.1016/j.ifacol.2018.09.610 2018-10-17 OPUS4-53000 Vortrag Viefhues, Eva Stochastic subspace-based damage detection of a temperature affected beam structure Structural health monitoring (SHM) of civil structures often is limited due to changing environmental conditions, as those changes affect the structural dynamical properties in a similar way like damages can do. In this article, an approach for damage detection under changing temperatures is presentedand applied to a beam structure. The used stochastic subspace-based algorithm relies on a reference null space estimate, which is confronted to data from the testing state in a residual function. For damage detection the residual is evaluated by means of statistical hypothesis tests. Changes of the system due to temperature effects are handled with a model interpolation approach from linear parameter varying system theory. From vibration data measured in the undamaged state at some few reference temperatures, a model of the dynamic system valid for the current testing temperature is interpolated. The reference null space and the covariance matrix for the hypothesis test is computed from this interpolated model. This approach has been developed recently and was validated in an academic test case on simulations of a mass-spring-damper. In this paper, the approach is validated experimentally on a beam structure under varying temperature conditions in a climate chamber. Compared to other approaches, the interpolation approach leads to significantly less false positive alarms in the reference state when the structure is exposed to different temperatures, while faults can still be detected reliably 2021 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10 Online meeting 30.06.2021 2021-07-26 OPUS4-55774 Dissertation Viefhues, Eva Subspace-based damage detection in engineering structures considering reference uncertainties and temperature effects Automated vibration-based damage detection is of increasing interest for structural health monitoring of engineering structures. In this context, stochastic subspace-based damage detection (SSDD) compares measurements from a testing state to a data-driven reference model in a statistical framework. In this thesis theoretical developments have been proposed to improve the robustness of SSDD for realistic applications conditions. First, a statistical test has been proposed considering the statistical uncertainties about the model obtained from the reference data. This leads to a precise description of the test's distribution properties and damage detection thresholds. Second, an approach has been developed to account for environmental effects in SSDD. Based on reference measurements at few different environmental conditions, a test is derived with respect to an adequate interpolated reference. The proposed methods are validated in numerical simulations and applied to experimental data from the laboratory and outdoor structures. Universite de Rennes Universite de Rennes 2021 1 191 2022-09-21 OPUS4-48244 Vortrag Viefhues, Eva Subspace-based Damage Detection with Rejection of the Temperature Effect and Uncertainty in the Reference 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. 2019 International Operational Modal Analysis Conference Copenhagen, Danmark 13.05.2019 15.05.2019 2019-06-20 OPUS4-50195 Vortrag Viefhues, Eva Subspace-based damage detection handling temperature effects and uncertainty in the reference 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. 2019 Abteilungs-Vortragsseminar Abteilung 7 Bauwerksicherheit Berlin, Germany 28.11.2019 2020-01-13 OPUS4-52366 Vortrag Viefhues, Eva Fault detection for linear parameter varying systems under changes in the process noise covariance Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only Systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models { each estimated from data measured in a reference state { are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then con icts May arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. 2020 21st IFAC World Congress Berlin, Germany 13.07.2020 2021-03-31 OPUS4-57449 Zeitschriftenartikel Titscher, Thomas; van Dijk, T.; Kadoke, Daniel; Robens-Radermacher, Annika; Herrmann, Ralf; Unger, Jörg F. Bayesian model calibration and damage detection for a digital twin of a bridge demonstrator Using digital twins for decision making is a very promising concept which combines simulation models with corresponding experimental sensor data in order to support maintenance decisions or to investigate the reliability. The quality of the prognosis strongly depends on both the data quality and the quality of the digital twin. The latter comprises both the modeling assumptions as well as the correct parameters of these models. This article discusses the challenges when applying this concept to realmeasurement data for a demonstrator bridge in the lab, including the data management, the iterative development of the simulation model as well as the identification/updating procedure using Bayesian inference with a potentially large number of parameters. The investigated scenarios include both the iterative identification of the structural model parameters as well as scenarios related to a damage identification. In addition, the article aims at providing all models and data in a reproducibleway such that other researcher can use this setup to validate their methodologies. Hoboken, NJ Wiley 2023 Engineering reports 1 27 urn:nbn:de:kobv:b43-574496 10.1002/eng2.12669 https://creativecommons.org/licenses/by/4.0/deed.de 2023-05-11 OPUS4-54189 Zeitschriftenartikel Thiele, Marc; Pirskawetz, Stephan Analysis of damage evolution in concrete under fatigue loading by acoustic emission and ultrasonic testing The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods. Basel MDPI 2022 Materials 15 1 341 355 urn:nbn:de:kobv:b43-541891 10.3390/ma15010341 https://creativecommons.org/licenses/by/4.0/deed.de 2022-01-05 OPUS4-55422 Beitrag zu einem Tagungsband Thiele, Marc; Makris, Ralf Aign, J. Reinforcement bar and reinforcement bar splicing systems under impact loading - Experimental tests and test specification Reinforced concrete is a widely used material for power generation structures, where load scenarios like impact loadings need to be considered. In this context mechanical splicing systems for the connection of reinforcement bars are of specific interest and impact resistance for the splicing systems has to be verified. High speed tensile tests need to be performed on splicing systems for reinforcement bars to confirm the capability of the coupler to resist impact loading. Furthermore, the ability of the reinforcement steel to dissipate energy by ductile behaviour with pronounced plastic strains should be confirmed by these tests. During the last decades comprehensive experiences were developed at BAM performing high speed tensile tests on reinforcement bars as well as on several splicing systems. For the lack of available standards defining these tests in detail an appropriate test procedure was developed and continuously optimized during this period at BAM. The test procedure is partially based on testing principles adapted from available standards. The main intention behind this test procedure is to perform high-speed tensile tests with a specific constant strain rate generated at the specimen. Furthermore, main objective was to establish a procedure to guarantee the comparability of test results for different diameter of reinforcement as well as for different types of couplers. Besides the pure execution of the high-speed tensile tests, the test specification also declares how to evaluate the measurements and the test results. Finally, some typical results will be presented in this contribution. 2022 Conference Proceedings SMIRT 26 SMIRT 26 Potsdam, Germany 10.07.2022 15.07.2022 1 10 2022-08-03 OPUS4-52507 misc Thiele, Marc; Makris, Ralf Specification for high-speed tensile tests on reinforcement bar coupler systems This document presents the specification for the execution and evaluation of high-speed tensile tests on reinforcement bar coupler systems. This specification was developed at BAM - Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing, Germany) - following test principles from related international standards. The present document represents the latest status of the test specification. It is noted that until 2010 the test procedure was characterised on a test velocity based on L0. In an improved test conception and after intensive investigations in cooperation with industry partners, this procedure has been updated to consider instead a test velocity based on Lr, since this warrants more comparable and meaningful results. V01 Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) 2021 1 29 urn:nbn:de:kobv:b43-525075 10.26272/opus4-52507 https://creativecommons.org/licenses/by-nd/4.0/deed.de 2021-05-05 OPUS4-48943 Beitrag zu einem Tagungsband Thiele, Marc; Hille, Falk; Makris, Ruben Helmerich, Rosemarie; Ilki, A.; Motavalli, M. Comparison of fatigue crack detection methods for high-cyclic loaded steel structures At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety. Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge. For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required. This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures. 2019 Proceedings of SMAR 2019 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Potsdam, Germany 27.08.2019 29.08.2019 Th.2.A.1-1 Th.2.A.1-8 urn:nbn:de:kobv:b43-489433 https://creativecommons.org/licenses/by/4.0/deed.de 2019-09-16 OPUS4-51356 Vortrag Thiele, Marc Fatigue crack detection methods for high-cyclic loaded steel structures and challenges in mechanical testing For the generation of renewable energy offshore wind farms play an important role. The majority of these wind generators are connected to steel foundation structures. Steady increasing power output of these wind turbines leads to new challenges as well for engineers of the related support structures. Caused by the high-cyclic loading of these structures by wind and waves fatigue plays a very important role. Besides the consideration of fatigue within the design process it is additionally an important topic and challenge to monitor the existing steel structures relating to potential fatigue cracks occurring during their lifetime. This plays a role for a fundamental understanding of mechanisms as investigated in testing but also for inspection in real structures. Since the structures of the offshore wind generators are very large and in addition partially under water effective and reliable methods for fatigue crack detection are required. This contribution will present results of recent investigations on different crack detection methods applied on high-cycle fatigue tests on small welded steel samples as well as on welded steel components. The comparison of these measurements will show what are the advantages and disadvantages of the different methods and which method is potentially more suitable for the application on real offshore wind structures. It is outlined where challenges for detection methods exist. Furthermore, in this context the resulting challenges for the execution of material testing especially caused by the increasing dimensions of wind energy converters will by exemplarily presented. 2020 EERA JP Wind & SETWind Online Annual Event 2020 Online meeting 14.09.2020 18.09.2020 2020-10-01 OPUS4-48944 Vortrag Thiele, Marc Comparison of fatigue crack detection methods for high-cyclic loaded steel structures At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety. Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge. For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required. This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures. 2019 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Potsdam, Germany 27.08.2019 29.08.2019 2019-09-16 OPUS4-48945 Vortrag Thiele, Marc Fatigue in Concrete The current knowledge about fatigue behavior of concrete is still incomplete. This concerns especially the progress of fatigue which precedes the fatigue failure. An overview on the fatigue behaviour in concrete is given. Therefore, the process of fatigue itself under cyclic compressive loading was investigated in a systematic and comprehensive way. The aim of this investigation was to obtain a deeper insight and to provide a better understanding of the damage process occurring within the material during fatigue loading. 2019 1st Infrastar Training School IFSTTAR, Nantes, France 08.04.2019 12.04.2019 2019-09-16 OPUS4-47511 Zeitschriftenartikel Teng, Jun; Tang, De-Hui; Zhang, Xiao; Hu, Wei-Hua; Said, Samir; Rohrmann, Rolf G. Automated modal analysis for tracking structural change during construction and operation phases The automated modal analysis (AMA) technique has attracted significant interest over the last few years, because it can track variations in modal parameters and has the potential to detect structural changes. In this paper, an improved density-based spatial clustering of applications with noise (DBSCAN) is introduced to clean the abnormal poles in a stabilization diagram. Moreover, the optimal system model order is also discussed to obtain more stable poles. A numerical Simulation and a full-scale experiment of an arch bridge are carried out to validate the effectiveness of the proposed algorithm. Subsequently, the continuous dynamic monitoring system of the bridge and the proposed algorithm are implemented to track the structural changes during the construction phase. Finally, the artificial neural network (ANN) is used to remove the temperature effect on modal frequencies so that a health index can be constructed under operational conditions. Basel, Switzerland MDPI AG 2019 Sensors 19 4 927, 1 23 urn:nbn:de:kobv:b43-475116 10.3390/s19040927 https://creativecommons.org/licenses/by/4.0/deed.de 2019-03-11 OPUS4-48952 Zeitschriftenartikel Straub, D.; Schneider, Ronald; Bismut, E.; Kim, H.-J. Reliability analysis of deteriorating structural systems 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. Elsevier Ltd. 2020 Structural Safety 82 Paper 101877, 1 10.1016/j.strusafe.2019.101877 2019-09-16 OPUS4-58381 Zeitschriftenartikel Strangfeld, Christoph; Stolpe, Heiko; Wiehle, Philipp Moisture diffusion affected by the Knudsen effect in temporal changing pore networks Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores (less than1 µm), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption. In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany. The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. These effects are prominent in the meso-pore range and might significantly alter the effective diffusion coefficient. Amsterdam, Niederlande Elsevier Ltd. 2023 Materials Today: Proceedings 1 8 urn:nbn:de:kobv:b43-583811 10.1016/j.matpr.2023.09.034 https://creativecommons.org/licenses/by/4.0/deed.de 2023-09-21 OPUS4-57139 Beitrag zu einem Tagungsband Strangfeld, Christoph; Stolpe, Heiko; Wiehle, Philipp Moisture diffusion affected by the Knudsen effect in temporal changing pore networks Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores (< 1 µm), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption. In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany. The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. This effect becomes most prominent in the meso-pore range and might alter the effective diffusion coefficient by more than 100 %. Champs-sur-Marne RILEM 2023 Proceedings of the 4th international congress on materials & structural stability 4th International Congress on Materials & Structural Stability Rabat, Morocco 08.03.2023 10.03.2023 1 8 urn:nbn:de:kobv:b43-571391 https://creativecommons.org/licenses/by/4.0/deed.de 2023-03-15 OPUS4-57140 Vortrag Strangfeld, Christoph Moisture diffusion affected by the Knudsen effect in temporal changing pore networks Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores ( 1 m), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption. In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany. The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. This effect becomes most prominent in the meso-pore range and might alter the effective diffusion coefficient by more than 100 %. 2023 4th International Congress on Materials & Structural Stability Rabat, Morocco 08.03.2023 10.03.2023 2023-03-14 OPUS4-45020 Posterpräsentation Spitzer, Stefan; Recknagel, Christoph BAM-Monitoringkompetenz am Beispiel des Projekts INFUSE-SensoJoint Datenmanagement der realen Beanspruchungen von Betonautobahnen von der definierten Datenerfassung über Datenverwaltung, Datenübertragung bis zur Datenauswertung 2018 Workshop Digitaler Zwilling BAM, Berlin, Germany 04.06.2018 04.06.2018 2018-06-04 OPUS4-45124 Posterpräsentation Spitzer, Stefan BAM-Monitoringkompetenz am Beispiel des Projekts INFUSE - SensoJoint BAM-Monitoringkompetenz mit Fokus auf das Datenmanagement der realen Beanspruchungen von Betonautobahnen von der definierten Datenerfassung über Datenverwaltung, Datenübertragung bis zur Datenauswertung am Beispiel des Projekts 7183-Infuse. 2018 Workshop Digitaler Zwilling BAM Berlin, Germany 04.06.2018 2018-06-07 OPUS4-46405 Vortrag Song, Jiaojiao Track-soil calculation and measurement of damaged and repaired slab tracks Calculation of the behaviour of damaged slab tracks have been performed with ANSYS and with a combined finite-element boundary-element Programme. Different damage lengths have been analysed and the best fit to the measurements has been chosen. 2018 Seminar on Railway Engineering Tongji University Shanghai, People's Republic of China 21.09.2018 21.09.2018 2018-10-31 OPUS4-51590 Beitrag zu einem Tagungsband Simon, Patrick; Schneider, Ronald; Viefhues, Eva; Said, Samir; Herrmann, Ralf; Baeßler, Matthias Papadrakis, M.; Fragiadakis, M.; Papadimitriou, C. Vibration-based Structural Health Monitoring of a Reinforced Concrete Beam Subjected to Varying Ambient Conditions Using Bayesian Methods 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. Athens, Greece Institute of Structural Analysis and Antiseismic Research, School of Civil Engineering, National Technical University of Athens (NTUA) EASD - European Association for Structural Dynamics 2020 Proceedings of EURODYN 2020, XI International Conference on Structural Dynamics 978-618-85072-2-7 EURODYN 2020, XI International Conference on Structural Dynamics Online meeting 23.11.2020 26.11.2020 1254 2020-11-30 OPUS4-54126 Beitrag zu einem Tagungsband Simon, Patrick; Schneider, Ronald; Baeßler, Matthias; Recknagel, Christoph Cunha, Á.; Caetano, E. Enhancing structural models with material tests and static response data - a case study considering a steel beam with asphalt layer subject to temperature variations Gradual or sudden changes in the state of structural systems caused, for example, by deterioration or accidental load events can influence their load-bearing capacity. Structural changes can be inferred from static and/or dynamic response data measured by structural health monitoring systems. However, they may be masked by variations in the structural response due to varying environmental conditions. Particularly, the interaction of nominally load-bearing components with nominally non-load bearing components exhibiting characteristics that vary as a function of the environmental conditions can significantly affect the monitored structural response. Ignoring these effects may hamper an inference of structural changes from the monitoring data. To address this issue, we adopt a probabilistic model-based framework as a basis for developing digital twins of structural systems that enable a prediction of the structural behavior under varying ambient condition. Within this framework, different types of data obtained from real the structural system can be applied to update the digital twin of the structural system using Bayesian methods and thus enhance predictions of the structural behavior. In this contribution, we implement the framework to develop a digital twin of a simply supported steel beam with an asphalt layer. It is formulated such that it can predict the static response of the beam in function of its temperature. In a climate chamber, the beam was subject to varying temperatures and its static response wass monitored. In addition, tests are performed to determine the temperature-dependent properties of the asphalt material. Bayesian system identification is applied to enhance the predictive capabilities of the digital twin based on the observed data. International Society for Structural Health Monitoring of Intelligent Infrastructure (ISHMII) 2021 International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-10) International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-10) Online meeting 30.06.2021 02.07.2021 1537 1544 2021-12-22 OPUS4-52809 Beitrag zu einem Tagungsband Simon, Patrick; Schneider, Ronald; Baeßler, Matthias Yokota, H.; Frangopol, D. M. Bayesian system identification of a reinforced concrete beam subject to temperature variations based on static response data Changes in the measured response of structural systems can be an indication of structural damages. However, such changes can also be caused by the effect of varying environmental conditions. To detect, localize and quantify changes or damages in structural systems subject to varying environmental conditions, physics-based models of the structural systems have to be applied which explicitly account for the influence of ambient conditions on the structural behavior. Data obtained from the structural systems should be used to calibrate the models and update predictions. Bayesian system identification is an effective framework for this task. In this paper, we apply this framework to learn the parameters of two competing structural models of a reinforced concrete beam subject to varying temperatures based on static response data. The models describe the behavior of the beam in the uncracked and cracked condition. The data is collected in a series of load tests in a climate chamber. Bayesian model class selection is then applied to infer the most plausible condition of the beam conditional on the available data. CRC Press 2021 Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020) Online meeting 11.04.2021 15.04.2021 934 941 10.1201/9780429279119-125 2021-06-14 OPUS4-55493 Beitrag zu einem Tagungsband Simon, Patrick; Herrmann, Ralf; Schneider, Ronald; Hille, Falk; Baeßler, Matthias; El-Athman, Rukeia Research Data Management of Structural Health Monitoring Projects and Subsequent Applications of Artificial Intelligence Methods 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. Boca Raton CRC Press 2022 Bridge safety, maintenance, management, life-cycle, resilience and sustainability - Proceedings of the eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 978-1-032-35623-5 11th International Conference on Bridge Maintenance, Safety and Management (IABMAS2022) Barcelona, Spain 11.07.2022 15.07.2022 1061 1068 10.1201/9781003322641-127 2022-08-16 OPUS4-55492 Zeitschriftenartikel Simon, Patrick; Helmrich, M.; Herrmann, Ralf; Schneider, Ronald; Baeßler, Matthias; Lorelli, S.; Morgenthal, G. Maintalbrücke Gemünden: Bauwerksmonitoring und -identifikation aus einem Guss Die Infrastruktursysteme der Industriestaaten erfordern heute und in Zukunft ein effizientes Management bei alternder Bausubstanz, steigenden Lasten und gleichbleibend hohem Sicherheitsniveau. Digitale Technologien bieten ein großes Potenzial zur Bewältigung der aktuellen und künftigen Herausforderungen im Infrastrukturmanagement. Im BMBF-geförderten Projekt Bewertung alternder Infrastrukturbauwerke mit digitalen Technologien (AISTEC) wird untersucht, wie unterschiedliche Technologien und deren Verknüpfung gewinnbringend eingesetzt werden können. Am Beispiel der Maintalbrücke Gemünden werden ein sensorbasiertes Bauwerksmonitoring, bildbasierte Inspektion mit durch Kameras ausgestatteten Drohnen (UAS) und die Verknüpfung digitaler Bauwerksmodelle umgesetzt. Die aufgenommenen Bilder dienen u. a. als Grundlage für spätere visuelle Anomaliedetektionen und eine 3D-Rekonstruktion, welche wiederum für die Kalibrierung und Aktualisierung digitaler Tragwerksmodelle genutzt werden. Kontinuierlich erfasste Sensordaten werden ebenfalls zur Kalibrierung und Aktualisierung der Tragwerksmodelle herangezogen. Diese Modelle werden als Grundlage für Anomaliedetektionen und perspektivisch zur Umsetzung von Konzepten der prädiktiven Instandhaltung verwendet. Belastungsfahrten und historische Daten dienen in diesem Beitrag der Validierung von kalibrierten Tragwerksmodellen. Berlin Ernst & Sohn 2022 Bautechnik 99 3 163 172 urn:nbn:de:kobv:b43-554924 10.1002/bate.202100102 https://creativecommons.org/licenses/by/4.0/deed.de 2022-08-16 OPUS4-54130 Vortrag Simon, Patrick Enhancing structural models with material tests and static response data - a case study considering a steel beam with asphalt layer subject to temperature variations Gradual or sudden changes in the state of structural systems caused, for example, by deterioration or accidental load events can influence their load-bearing capacity. Structural changes can be inferred from static and/or dynamic response data measured by structural health monitoring systems. However, they may be masked by variations in the structural response due to varying environmental conditions. Particularly, the interaction of nominally load-bearing components with nominally non-load bearing components exhibiting characteristics that vary as a function of the environmental conditions can significantly affect the monitored structural response. Ignoring these effects may hamper an inference of structural changes from the monitoring data. To address this issue, we adopt a probabilistic model-based framework as a basis for developing digital twins of structural systems that enable a prediction of the structural behavior under varying ambient condition. Within this framework, different types of data obtained from real the structural system can be applied to update the digital twin of the structural system using Bayesian methods and thus enhance predictions of the structural behavior. In this contribution, we implement the framework to develop a digital twin of a simply supported steel beam with an asphalt layer. It is formulated such that it can predict the static response of the beam in function of its temperature. In a climate chamber, the beam was subject to varying temperatures and its static response wass monitored. In addition, tests are performed to determine the temperature-dependent properties of the asphalt material. Bayesian system identification is applied to enhance the predictive capabilities of the digital twin based on the observed data. 2021 International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-10) Online meeting 30.06.2021 02.07.2021 2021-12-21 OPUS4-52812 Vortrag Simon, Patrick Bayesian system identification of a reinforced concrete beam subject to temperature variations based on static response data Changes in the measured response of structural systems can be an indication of structural damages. However, such changes can also be caused by the effect of varying environmental conditions. To detect, localize and quantify changes or damages in structural systems subject to varying environmental conditions, physics-based models of the structural systems have to be applied which explicitly account for the influence of ambient conditions on the structural behavior. Data obtained from the structural systems should be used to calibrate the models and update predictions. Bayesian system identification is an effective framework for this task. In this paper, we apply this framework to learn the parameters of two competing structural models of a reinforced concrete beam subject to varying temperatures based on static response data. The models describe the behavior of the beam in the uncracked and cracked condition. The data is collected in a series of load tests in a climate chamber. Bayesian model class selection is then applied to infer the most plausible condition of the beam conditional on the available data. 2021 Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020) Online meeting 11.04.2021 15.04.2021 2021-06-14 OPUS4-52869 Vortrag Simon, Patrick Experimente in der Klimakammer Im Rahmen des Verbundtreffens des Vorhabens AISTEC werden akutelle Versuche aus der Großklimakammer des FB 7.2 präsentiert. 2021 5. Verbundtreffen AISTEC Online meeting 24.06.2021 2021-06-28 OPUS4-55494 Vortrag Simon, Patrick Research Data Management of Structural Health Monitoring Projects and Subsequent Applications of Artificial Intelligence Methods 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. 2022 11th International Conference on Bridge Maintenance, Safety and Management (IABMAS2022) Barcelona, Spain 11.07.2022 15.07.2022 2022-08-16 OPUS4-55495 Vortrag Simon, Patrick Sensorbasierte Systemidentifikation Die aktuelle Instandhaltungsstrategien von Ingenieurbauwerken arbeiten zustandsbasiert und stützen sich auf visuelle Inspektionen in kurzen, starren Intervallen. Beim Übergang zu Predicitive-Maintenance-Strategien können Sensordaten eigesetzt werden um Prognosemodelle der Bauwerke zu aktualisieren. Ein erster Schritt hierzu ist die sensorbasierte Systemidentifikation. 2022 Abschlussveranstaltung AISTEC Berlin, Germany 02.05.2022 2022-08-16 OPUS4-49265 Vortrag Simon, Patrick Structural Health Monitoring (SHM) unter Temperatureinflüssen Beim Structural Health Monitoring (SMH) besteht eine der Hauptsächlichen Störgrößen im Einfluss der Umgebungsbedingungen, insbesondere der Temperatur. Es wird ein Einblick in die Problemstellung gegeben sowie Lösungsansätze diskutiert und aktuelle Forschung an der BAM vorgestellt. 2019 Internes Arbeitskolloquium TU Berlin Berlin, Germany 11.10.2019 2019-10-16 OPUS4-51732 Vortrag Simon, Patrick Vibration-based Structural Health Monitoring of a Reinforced Concrete Beam Subjected to Varying Ambient Conditions Using Bayesian Methods 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. 2020 EURODYN 2020, XI International Conference on Structural Dynamics Online meeting 23.11.2020 26.11.2020 2020-12-07 OPUS4-47702 Vortrag Simon, Patrick Untersuchungsmethoden klimatisch belasteter Bauteile - Projektupdate BAM 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. 2019 Erstes Verbundtreffen AISTEC Weimar, Germany 21.03.2019 21.03.2019 2019-04-02 OPUS4-58005 Vortrag Simon, Patrick Zustandsbewertung von Bauwerken unter veränderlichen Umgebungsbedingungen mittels Structural Health Monitoring 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. 2023 Forschungskolloquium, Institut für Konstruktiven Ingenieurbau, Bauhaus-Universität Weimar Weimar, Germany 28.06.2023 2023-07-31 OPUS4-58793 Zeitschriftenartikel Signorini, Cesare; Bracklow, Franz; Hering, Marcus; Butler, Marko; Leicht, Lena; Schubert, Thomas; Beigh, Mirza A.B.; Beckmann, Birgit; Curbach, Manfred; Mechtcherine, Viktor Ballistic limit and damage assessment of hybrid fibre-reinforced cementitious thin composite plates under impact loading 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. Elsevier Ltd. 2023 Journal of Building Engineering 80 1 21 10.1016/j.jobe.2023.108037 2023-11-13 OPUS4-45227 Beitrag zu einem Tagungsband Shamsuddoha,, Md; Hüsken, Götz; Pirskawetz, Stephan; Baeßler, Matthias; Kühne, Hans-Carsten; Thiele, Marc Remediation of Cracks Formed in Grouted Connections of Offshore Energy Structures under Static Loads 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. International Society of Offshore and Polar Engineers (ISOPE) 2018 Proceedings of the Twenty-eighth (2018) International Ocean and Polar Engineering Conference Twenty-eighth (2018) International Ocean and Polar Engineering Conference Sapporo, Japan 10.06.2018 15.06.2018 120 126 2018-06-20 OPUS4-48712 Zeitschriftenartikel Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Long-term mechanical and shrinkage properties of cementitious grouts for structural repair 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. 4 avenue du Recteur Poincaré, 75016 Paris, France RILEM Publications SARL 2019 RILEM Technical Letters 4 International Conference on Sustainable Materials, Systems and Structures (SMSS 2019) Rovinj, Croatia 20.03.2019 22.03.2019 9 15 10.21809/rilemtechlett.2019.82 2019-08-19 OPUS4-45922 Zeitschriftenartikel Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Ternary mix design of grout material for structural repair using statistical tools 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. Elsevier Ltd. 2018 Construction and Building Materials 189 170 180 10.1016/j.conbuildmat.2018.08.156 2018-09-13 OPUS4-46476 Beitrag zu einem Tagungsband Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Alexander, M.G.; Beushausen, H.; Dehn, F.; Moyo, P. Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs 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. MATEC Web of Conferences 2018 Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) 199 International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) Cape Town, South Africa 19.11.2018 21.11.2018 07006-1 07006-7 urn:nbn:de:kobv:b43-464769 10.1051/matecconf/201819907006 https://creativecommons.org/licenses/by/4.0/deed.de 2018-11-07 OPUS4-47831 Beitrag zu einem Tagungsband Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems 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. EDP Sciences 2019 MATEC Web of Conferences 278 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) University of Lisbon, Portugal 26.09.2018 28.09.2018 Article Number 01001 urn:nbn:de:kobv:b43-478319 10.1051/matecconf/201927801001 https://creativecommons.org/licenses/by/4.0/deed.de 2019-04-17 OPUS4-45226 Vortrag Shamsuddoha, Md Remediation of Cracks Formed in Grouted Connections of Offshore Energy Structures under Static Loads 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. 2018 Twenty-eighth (2018) International Ocean and Polar Engineering Conference Sapporo, Japan 10.06.218 15.06.2018 2018-06-20 OPUS4-46155 Vortrag Shamsuddoha, Md Superplasticizer and shrinkage reducing admixture dosages for microfine cement in grout systems 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. 2018 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) University of Lisbon, Portugal 26.09.2018 28.09.2018 2018-10-05 OPUS4-46712 Vortrag Shamsuddoha, M. Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs 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. 2018 International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) Cape Town, South Africa 19.11.2018 21.11.2018 2018-11-26 OPUS4-44285 Zeitschriftenartikel Schwedler, Michael; Dörfeldt, Stefan; Lüddecke, Falk; Seidel, Marc; Thiele, Marc Kurrer, Karl-Eugen Einflussfaktoren auf die Vorspannkraft von Schrauben mit Durchmessern bis M72 in Ringflanschverbindungen 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. Berlin Wilhelm Ernst und Sohn 2018 Stahlbau 87 2 149 161 10.1002/stab.201810571 2018-02-23 OPUS4-52769 Beitrag zu einem Tagungsband Schneider, Ronald; Straub, D. Matos, J.C.; Lourenço, P.B.; Oliveira, D.V.; Branco, J.; Proske, D.; Silva, R.A.; Sousa, H.S. Cumulative Failure Probability of Deteriorating Structures: Can It Drop? 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. Cham, Switzerland Springer 2021 18th International Probabilistic Workshop. IPW 2020. Lecture Notes in Civil Engineering 153 18th International Probabilistic Workshop (IPW 2020) Online meeting 12.05.2021 14.05.2021 253 264 10.1007/978-3-030-73616-3_18 2021-06-09 OPUS4-46434 Beitrag zu einem Tagungsband Schneider, Ronald; Rogge, Andreas; Thöns, S.; Bismut, E.; Straub, D. Caspeele, Robby; Taerwe, Luc; Frangopol, Dan M. A sampling-based approach to identifying optimal inspection and repair strategies for offshore jacket structures 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. London Taylor & Francis Group 2019 Proceedings of the sixth international symposium on life-cycle civil engineering (IALCCE 2018) 978-1-138-62633-1 The sixth international symposium on life-cycle civil engineering (IALCCE 2018) Ghent, Belgien 28.10.2018 31.10.2018 1081 1088 2018-11-05 OPUS4-51333 Vortrag Schneider, Ronald; Herrmann, Ralf Sensorbasiertes Monitoring der Maintalbrücke Gemünden 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. 2020 4. Verbundtreffen AISTEC Weimar, Germany 24.09.2020 24.09.2020 2020-09-30 OPUS4-54531 Beitrag zu einem Tagungsband Schneider, Ronald; Cuéllar, Pablo; Baeßler, Matthias Probabilistic approaches to the design and assessment of offshore foundations considering spatially varying site conditions 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. ASRANet Ltd 2022 Proceedings of the 3rd International Conference on Structural Integrity for Offshore Energy Industry (SI 2021) 978-1-8383226-3-2 3rd International Conference on Structural Integrity for Offshore Energy Industry (SI 2021) Online meeting 15.11.2021 16.11.2021 9 17 2022-03-24 OPUS4-53748 Vortrag Schneider, Ronald Probabilistic approaches to the design and assessment of offshore foundations considering spatially varying site conditions 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. 2021 3rd International Conference on Structural Integrity for Offshore Energy Industry (SI 2021) Online meeting 15.11.2021 16.11.2021 2021-11-17 OPUS4-53749 Vortrag Schneider, Ronald A risk-based framework for optimizing inspection and maintenance of deteriorating structures monitored by vibration-based monitoring systems 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. 2021 EERA JP Wind WORKSHOP on Ongoing research in offshore wind structures Online meeting 16.09.2021 17.09.2021 2021-11-17 OPUS4-52982 Vortrag Schneider, Ronald Sensorbasiertes Monitoring (AP4 + AP7): Ein Überblick 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. 2021 AISTEC 5. Verbundtreffen Online meeting 24.06.2021 2021-07-21 OPUS4-52766 Vortrag Schneider, Ronald Integrating vibration monitoring into risk-based inspection and maintenance planning for deteriorating structural systems A reliability and risk-based framework for integrating vibration monitoring data in the planning of inspection and maintenance of deteriorating structural systems is discussed and demonstrated in a numerical example. 2021 Wind Energy Science Conference (WESC 2021) Online Meeting 25.05.2021 28.05.2021 2021-06-09 OPUS4-52767 Vortrag Schneider, Ronald SysPark: a software tool for system-wide adaptive planning of inspections of turbine support structures in offshore wind farms 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. 2021 Wind Energy Science Conference (WESC 2021) Online Meeting 25.05.2021 28.05.2021 2021-06-09 OPUS4-52768 Vortrag Schneider, Ronald Towards predictive maintenance of bridges Key features of predictive maintenance of structural systems are discussed and demonstrated in two examples. Challenges and needs for further research are discussed. 2021 Workshop Bridge Maintenance Online Meeting 09.04.2021 2021-06-09 OPUS4-52770 Vortrag Schneider, Ronald Cumulative failure probability of deteriorating structures: Can it drop? 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. 2021 18th Internatinoal Probabilistic Workshop (IPW 2020) Online Meeting 12.05.2021 14.05.2021 2021-06-09 OPUS4-55496 Vortrag Schneider, Ronald Belastungsversuch und Methodenvalidierung an der Maintalbrücke Gemünden Im Projekt AISTEC wurden Methoden entwickelt, die der prädiktiven Instandhaltung von Ingenieurbauwerken dienen. Zur Validierung dieser Methoden wurden an einem Referenzbauwerk - der Maintalbrücke Gemünden - Belastungstests durchgeführt. 2022 Abschlussveranstaltung AISTEC Berlin, Germany 02.05.2022 2022-08-16 OPUS4-55770 Vortrag Schneider, Ronald Überwachung von Brücken mit digitalen Methoden 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. 2022 BVPI Arbeitstagung 2022 Berlin, Germany 16.09.2022 17.09.2022 2022-09-21 OPUS4-51297 Dissertation Schneider, Ronald Time-variant reliability of deteriorating structural systems conditional on inspection and monitoring data 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. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) 2020 BAM-Dissertationsreihe 168 1 188 urn:nbn:de:kobv:b43-512977 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2020-09-24 OPUS4-50796 Vortrag Schneider, Ronald Kontinuierliches Bauwerksmonitoring - Sensor-basiert (AP4) 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. 2020 3. Verbundtreffen AISTEC Online meeting 05.05.2020 2020-05-20 OPUS4-48829 Beitrag zu einem Tagungsband Schneider, Ronald Effect of repair models on risk based optimal inspection strategies for support structures of offshore wind turbines 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. 2019 Proceedings of the 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) Potsdam, Germany 27.08.2019 29.08.2019 Paper Th.2.A.4, 1 8 urn:nbn:de:kobv:b43-488297 https://creativecommons.org/licenses/by/4.0/deed.de 2019-09-03 OPUS4-48830 Vortrag Schneider, Ronald Effect of repair models on risk based optimal inspection strategies for support structures of offshore wind turbines 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. 2019 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019) Potsdam, Germany 27.08.2019 29.08.2019 2019-09-03 OPUS4-46432 Vortrag Schneider, Ronald A sampling-based approach to identifying optimal inspection and repair strategies for offshore jacket structures 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. 2018 The Sixth International Symposium on Life-Cycle Civil Engineering (IALCCE 2018) Gent, Belgium 28.10.2018 31.10.2018 2018-11-05 OPUS4-46436 Vortrag Schneider, Ronald Risikoanalyse technischer Systeme: Aktivitäten an der BAM 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. 2018 4. Sitzung des Beirates „Infrastruktur“ der Bundesanstalt für Materialforschung und –prüfung (BAM) Berlin, Germany 19.04.2018 19.04.2018 2018-11-05 OPUS4-46437 Vortrag Schneider, Ronald Bayes'sche Analyse von Ingenieurmodellen Der Vortrag zeigt, dass Unsicherheiten in Ingenieurmodellen quantitativ mit Methoden der Wahrscheinlichkeitstheorie modelliert werden können. Zusätzlich können durch eine Bayes'sche Analyse probabilistische Ingenieurmodelle konsistent anhand von Daten „gelernt" werden. 2018 Workshop "Digitaler Zwilling" des BAM Koptenzzentrums „Modellierung und Simulation“ Berlin, Germany 04.06.2018 04.06.2018 2018-11-05 OPUS4-57811 Zeitschriftenartikel Schneider, Ronald Von der Datenerfassung bis zur Entscheidungsfindung: Jede Brücken-Überwachung bedarf einer Gesamtmethodik 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. Bundesvereinigung der Prüfingenieure für Bautechnik e. V. 2023 Der Prüfingenieur 62 76 83 2023-07-03 OPUS4-57863 Vortrag Schneider, Ronald Vibration-based system identification of a large steel box girder bridge 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. 2023 XII International Conference on Structural Dynamics (EURODYN 2023) Delft, Netherlands 02.07.2023 05.07.2023 2023-07-07 OPUS4-57864 Vortrag Schneider, Ronald Structural integrity management research at BAM This presentation provides an overview on the structural integrity management research at BAM. In addition, a framework for monitoring and risk-informed inspection and maintenance planning for offshore steel structures is presented. 2023 Structural Health Monitoring Using Statistical Pattern Recognition Berlin, Germany 20.03.2023 23.03.2023 2023-07-07 OPUS4-58101 Vortrag Schneider, Ronald Vibration-based system identification of a large steel box girder bridge 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. 2023 XII International Conference on Structural Dynamics (EURODYN 2023)) Delft, Netherlands 02.07.2023 05.07.2023 2023-09-04 OPUS4-54762 Beitrag zu einem Tagungsband Schepers, Winfried; Kulke, D. Ermittlung dynamischer Bodensteifigkeit aus konventionellen geotechnischen Berichten 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. Düsseldorf VDI-Verlag VDI Wissensforum 2022 7. VDI-Fachtagung Baudynamik 2379 978-3-18-092379-6 7. VDI-Fachtagung Baudynamik Würzburg, Germany 27.04.2022 28.04.2022 347 359 2022-05-16 OPUS4-58351 Beitrag zu einem Tagungsband Schepers, Winfried; Kulke, D. Wuttke, F.; Aji, H. D. B.; Özarmut, A. Anwendung von Korrelationen zwischen Sondierergebnissen und dynamischen Bodeneigenschaften 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. Kiel Deutsche Gesellschaft für Erdbebeningenieurwesen und Baudynamik (DGEB) e. V. und Christian-Albrechts-Universität zu Kiel 2023 Tagungsband der 18. D-A-CH-Tagung Erdbebeningenieurwesen und Baudynamik 978-3-930108-15-1 18. D-A-CH-Tagung Erdbebeningenieurwesen und Baudynamik Kiel, Germany 14.09.2023 15.09.2023 433 441 2023-09-20 OPUS4-58581 Vortrag Schepers, Winfried Korrelationen zwischen Sondierungen und dynamischen Bodeneigenschaften 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. 2023 18. D-A-CH-Tagung für Erdbebeningenieurwesen und Baudynamik Kiel, Germany 14.09.2023 15.09.2023 2023-10-16 OPUS4-58582 Vortrag Schepers, Winfried Cone penetration tests and dynamic soil properties 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. 2023 Eurodyn 2023 Delft, Netherlands 02.07.2023 05.07.2023 2023-10-16 OPUS4-58583 Vortrag Schepers, Winfried Recommendations on finite Element modelling of non-seismic excitation in soil-structure interaction problems 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. 2023 Eurodyn 2023 Delft, Netherlands 02.07.2023 05.07.2023 2023-10-16 OPUS4-54969 Zeitschriftenartikel Savidis, S.; Bergmann, M.; Schepers, Winfried; Fontara, I.-K. Wave propagation in inhomogeneous media via FE/PML method 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. Berlin Ernst & Sohn 2022 Geotechnik 45 2 98 107 10.1002/gete.202100028 2022-06-09 OPUS4-53726 Vortrag Sanayei, Mohammad Hassan; Farhat, A.; Luu, Li-Hua; Werner, L.; Rettinger, C.; Philippe, P.; Cuellar, Pablo Micromechanical framework for a 3D solid cohesion model - Implemantation, validation and perspectives 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. 2021 VII International Conference on Particle-Based Methods PARTICLES 2021 Hamburg, Germany 04.10.2021 2021-11-10 OPUS4-53716 Beitrag zu einem Tagungsband Sanayei, Mohammad Hassan; Farhat, A.; Luu, L.-H.; Werner, L.; Rettinger, C.; Philippe, P.; Cuellar, Pablo Micromechanical framework for a 3d solid cohesion model - implementation, validation and perspectives 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. 2021 Proceeding - VII International Conference on Particle-Based Methods PARTICLES 2021 VII International Conference on Particle-Based Methods PARTICLES 2021 Hamburg, Germany 04.10.2021 06.10.2021 1 10 2021-11-10 OPUS4-45506 Beitrag zu einem Tagungsband Said, Samir; Auersch, Lutz Prediction of explosion-induced ground and building vibrations - measured wave velocities, transfer functions and attenuation Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q  0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites. Gliwice, Poland Silesian University of Technology Press ICSV25 Local Committee in Hiroshima 2018 Proceedings of the 25th International Congress on Sound and Vibration, Sound of Peace Bell, 2018 978-83-7880-552-6 International Congress on Sound and Vibration (ICSV25) Hiroshima, Japan 08.07.2018 12.07.2018 1 8 2018-07-19 OPUS4-48495 Vortrag Said, Samir; Auersch, Lutz Measurement of slab track behaviour at different sites Measured train passages and hammer impacts in combination with track-soil calculation have been successfully used for the detection of damaged slab tracks. This approach is now extended to intact slab and ballast tracks. The vibrations of many tracks have been measured at several levels from rail, sleeper, track plate, base plate, base layer to the subsoil by velocity or acceleration sensors. The time histories have to be integrated once or twice to get the displacements. The displacement signals include an arbitrary time-dependent shift which must be eliminated or respected in the interpretation. On the other hand, the calculation of slab and ballast tracks have been done in frequency-wavenumber domain. The displacements along the track and the frequency-dependent compliance transfer functions can be calculated. The latter can be compared with the results of the hammer impacts on the track. The deformation of the track can be transformed to time histories for a whole train and compared to the measured train passages. Many slab (and ballast) tracks have been measured at different sites. The displacements of the tracks are presented, and the following parameters have been analysed in the measurement results: slab track vs. ballast track, different types of slab tracks, damaged slab tracks, different trains, switches at different measuring points, an elastic layer, the mortar layer, different soils at different places. The soil should have the dominant influence on the track-plate displacements. Slab and ballast track yield also big differences in maximum displacement and width of deformation. Some of the preceding aspects will be analysed in comparison of measurement and theory. 2019 26th International Congress on Sound and Vibration (ICSV26) Montreal, Canada 07.07.2019 11.07.2019 2019-07-18 OPUS4-45508 Vortrag Said, Samir Prediction of explosion-induced ground and building vibrations - measured wave velocities, transfer functions and attenuation Explosion-induced ground vibrations have been measured at several places. Results about the wave propagation are shown in this contribution. The particle velocities of the soil have been measured at up to 1000 m distance from the explosion and are presented as time records (seismograms) and one-third octave band spectra (transfer functions). The results are compared with the results of hammer impacts. The seismograms clearly show different wave types, compressional waves of the air, the water and the soil, and the Rayleigh wave. The hammer impacts yield good results up to 100 m and incorporate higher frequencies at about 50 Hz, whereas the explosion results in a ground vibration with frequencies around 10 Hz and a longer range of influence. Explosion and hammer excitations are evaluated for the wave velocities of the soil by using the wavenumber and the spatial auto-correlation method. The attenuation of the ground vibration amplitudes A with distance r can well be presented by a power law A ~ r -q. This type of amplitude-distance law and the corresponding power q > 1 are substantiated in the contribution. The influence of the charge weight W is evaluated as an additional power law A ~ W -p for each measuring site. The power is found quite similarly around q  0.6 as all sites have a medium soft soil such as sand and clay. The obtained amplitude-charge-distance law can be used to predict the explosion-induced ground and building vibrations at other sites. 2018 International Congress on Sound and Vibration (ICSV25) Hiroshima, Japan 08.07.2018 12.07.2018 2018-07-19 OPUS4-57019 Zeitschriftenartikel Sadowski, A.; Seidel, M.; Al-Lawati, H.; Azizi, E.; Balscheit, Hagen; Böhm, M.; Chen, Lei; van Dijk, I.; Doerich-Stavridis, C.; Kunle Fajuyitan, O.; Filippidis, A.; Winther Fischer, A.; Fischer, C.; Gerasimidis, S.; Karampour, H.; Kathirkamanathan, L.; Subramanian, S.; Topkaya, Cem; Wagner, H. N. R.; Wang, J.; Wang, J.; Kumar Yadav, K.; Yun, X.; Zhang, P. 8-MW wind turbine tower computational shell buckling benchmark - Part 1: An international 'round-robin' exercise An assessment of the elastic-plastic buckling limit state for multi-strake wind turbine support towers poses a particular challenge for the modern finite element analyst, who must competently navigate numerous modelling choices related to the tug-of-war between meshing and computational cost, the use of solvers that are robust to highly nonlinear behaviour, the potential for multiple near-simultaneously critical failure locations, the complex issue of imperfection sensitivity and finally the interpretation of the data into a safe and economic design. This paper reports on an international 'round-robin' exercise conducted in 2022 aiming to take stock of the computational shell buckling expertise around the world which attracted 29 submissions. Participants were asked to perform analyses of increasing complexity on a standardised benchmark of an 8-MW multi-strake steel wind turbine support tower segment, from a linear elastic stress analysis to a linear bifurcation analysis to a geometrically and materially nonlinear buckling analysis with imperfections. The results are a showcase of the significant shell buckling expertise now available in both industry and academia. This paper is the first of a pair. The second paper presents a detailed reference solution to the benchmark, including an illustration of the Eurocode-compliant calibration of two important imperfection forms. Oxford Elsevier Science 2023 Engineering failure analysis 148 1 23 10.1016/j.engfailanal.2023.107124 2023-02-20 OPUS4-59099 Beitrag zu einem Tagungsband Ritz, Sebastian; Loewe, Anna; Bauer, Jan Specialties of HAZID-Study for Large Unmanned Underwater Vehicles This paper scopes the specialties of a hazard identification study for large and extra-large unmanned undersea vehicles (UUVs). A generic node/function structure is derived from different large and extra-large UUV designs, partially own vehicle designs from research projects, and partially from commercial vehicles. For each node, a short overview of its components and the proper function or operations is defined. A set of guide words is used to prompt a hazard discussion for each node, which identifies unwanted functions, resulting in potential hazards and unmitigated consequences. Related to the SafeMASS-Report from DNV, this work concentrates on selected topics of the bridge-related function on voyage, control & monitoring, and abnormal situations. For unmanned vehicles without any person on board, these three topics become more important for underwater vehicles with very limited connectivity or temporary disruptions of communication whereby an operator in a remote-control center could only be provided with rough vehicle or mission states. Therefore, vehicle control, whether in hard- or software, must handle most tasks belonging to the considered functions automatically or autonomously. Hence, the most appropriate reactions of the system to unwanted system behavior must be implemented. This HAZID study could, on the one hand, be used as background for such an implementation, and on the other hand, it is used to verify the implemented actions on the risks and hazards. IEEE 2023 OCEANS 2023 - Limerick OCEANS 2023 - Limerick Limerick, Ireland 05.06.2023 08.06.2023 1 10 10.1109/OCEANSLimerick52467.2023.10244358 2023-12-11 OPUS4-49639 Beitrag zu einem Tagungsband Rica, S.; Van Baars, S.; Kullolli, Borana Ülgen, D.; Saygili, A.; Kahyaoglu, M. R.; Durmaz, S.; Toygar, O.; Göcügenci, A. The importance of the horizontal stresses on the bearing capacity of a foundation pile In case one wants to predict or design the bearing capacity of a foundation pile and there are no possibilities to perform an in-situ test, such as a Cone Penetration Test, the pile bearing capacity is in most cases estimated with analytical formulas. The most known and used method is the Meyerhof method published some decades ago. There are also other design methods such as derived from a certain failure mechanism around the pile tip, which is, in most cases, wedge failure mechanism. This failure mechanism was originally developed for a shallow (infinite) strip foundation, though. Therefore, it represents a plane failure mechanism. Numerical simulations on loaded foundation piles performed with the Plaxis software Show however, that the failure mechanism of a foundation pile represents a far more complex threedimensional failure mechanism around the pile tip. In addition, the existing analytical methods for foundation piles are based on the vertical stresses in the soil, as if the failure mechanism is the same as of a shallow foundation. Numerical simulations, performed in Plaxis show that, not the vertical, but the horizontal stresses, play an important role on the pile bearing capacity. Plaxis represents the stresses in the soil by using the procedure. So, different horizontal soil stresses are obtained for different values of the lateral earth pressure coefficient. The results show that the pile tip bearing capacity depends strongly on the horizontal stresses in the soil, but only for. The same results were observed by using a Material Point Method (MPM). Consequently, the analytical methods should estimate the pile bearing. Bodrum, Turkey 1st Mediterranean Young Geotechnical Engineers Conference Turkish Society for ISSMGE (ZMGM) 2019 2019 1st Mediterranean Young Geotechnical Engineers Conference Bodrum, Turkey 23.09.2019 24.09.2019 151 158 2019-11-21 OPUS4-50029 Zeitschriftenartikel Reimold, W. U.; Crosta, A. P.; Hasch, M.; Kowitz, Astrid; Hauser, N.; Sanchez, J. P.; Simoes, L. S. A.; de Sanchez, G. J.; Zaag, P. T. Shock deformation confirms the impact origin for the Cerro do Jarau, Rio Grande do Sul, Brazil, structure 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. Wiley 2018 Meteoritics & Planetary Science 54 10 2384 2394 10.1111/maps.13233 2019-12-16 OPUS4-57687 Vortrag Ratkovac, Mirjana Perspectives on Wind and Wave Load Reconstruction from SHM Data for Offshore Wind Turbines As many wind turbines approach the end of their design lifetime, from a technical point of view, comprehensive fatigue analysis of all critical parts is necessary to decide what comes after - continued operation, repowering, or decommissioning. Typically, it is a two-stage evaluation process consisting of a physical inspection of the structure and an analytical part to compare the design and actually experienced loading conditions. Structural health monitoring helps to reduce the uncertainties in the estimations by providing insight into deviations between the designed and the built structure. Furthermore, it allows the evaluation of the consumed fatigue lifetime by analyzing the strain measurements that mirror the actual structural response to experienced environmental and operational conditions. However, the measurement values are limited to a sparse number of instrumented spots on the structure, and further extrapolation to the non-instrumented (critical) sections is required to perform a complete fatigue assessment. One known approach is the external force reconstruction, which has only scarcely been considered for application in offshore wind turbines. In order to extend the previously developed thrust force reconstruction framework, this work discusses the possibilities and challenges of wind and wave loading reconstruction in offshore wind turbine support structures. 2023 4th International Conference on Health Monitoring of Civil & Maritime Structures (HeaMES 2023) Online meeting 12.06.2023 13.06.2023 2023-06-16 OPUS4-56654 Vortrag Pittner, Andreas; Winterkorn, René; Fabry, Cagtay; Rethmeier, Michael; Thiele, Marc; Baeßler, Matthias; Brauser, S. SmartWeld - Leichtbautechnik für Tragstrukturen von Offshore Windenergieanlagen Die Anwendung von Leichtbauprinzipien im Stahlbau, wie z.B. die Verwendung von aufgelösten Tragstrukturen, sog. Jackets-Fundamenten, bietet ein großes Potential zur Reduzierung des Ressourcenverbrauchs, insbesondere im Hinblick auf die benötigte Stahlmenge. In diesem Vortrag zeigen wir die Potenziale einer vollständigen Digitalisierung der schweißtechnischen Fertigungs- und Prüfkette auf, um eine vollautomatische Fertigung sowie Qualitätsprüfung von Rohrknoten als Schlüsselelement von Jackets-Fundamenten zu ermöglichen. Darüber hinaus wird der Zusammenhang zwischen der Geometrie der Nahtform und der resultierenden Ermüdungsfestigkeit durch numerische Methoden unter Einbeziehung bionischer Prinzipien bewertet. Es wird gezeigt, dass Hohlprofilknoten vollautomatisch unter Berücksichtigung von Geometrietoleranzen geschweißt werden können. Darüber hinaus konnte die Nahtform gemäß den numerischen Modellen hergestellt werden, was ein großes Potenzial für eine verlängerte Lebensdauer bietet. Anschließend werden die Verbesserungen bei der Ressourceneffizienz und die Reduzierung der Kohlendioxidemissionen durch eine Lebenszyklusanalyse bewertet. 2022 11. Zukunftskonferenz Wind & Maritim Rostock, Germany 01.09.2022 2022-12-21 OPUS4-56655 Vortrag Pittner, Andreas; Winterkorn, René; Fabry, Cagtay; Rethmeier, Michael; Ratkovac, Mirjana; Thiele, Marc; Baeßler, Matthias Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau Ziel des Verbundvorhabens „SmartWeld" ist es, für die schweißtechnische Fertigung von Stahlbaustrukturen exemplarisch am Beispiel von Hohlprofilknoten, welche als designrelevante Elemente von Gründungsstrukturen für Offshore-Windenergieanlagen (OWEA) einsetzbar sind, die Möglichkeiten des Leichtbaus unter konsequenter Digitalisierung der Fertigungskette aufzuzeigen, um einerseits die Ressourceneffizienz zu forcieren und gleichzeitig wettbewerbsfähige Fertigungsstrategien aufzuzeigen. Innerhalb von „SmartWeld" werden daher die Möglichkeiten einer wirtschaftlichen Fertigung von Leichtbau-Gründungsstrukturen am Beispiel aufgelöster Tragstrukturen (Jackets) aufgezeigt. Eine lastgerechte Auslegung der Schweißverbindungen nach bionischen Prinzipien ermöglicht, weitere Einsparpotenziale an Ressourcen bei gleichzeitiger Erhöhung der Lebensdauer zu erschließen. Die Ausnutzung konstruktiver Prinzipien des Leichtbaus zur Erzeugung innovativer und ressourcenschonender Produkte erfordert den Einsatz digitaler Werkzeuge in der Designphase, der virtuellen Absicherung, der Fertigung und Qualitätsüberwachung sowie nachgelagerten Bauteilprüfung zur Abbildung der Nutzungsphase. Im Rahmen der Arbeiten wird daher der gesamte Produktentstehungs- und Prüfprozess betrachtet. Dies beinhaltet das Design im Kontext des konstruktiven Leichtbaus, den schweißtechnischen Fertigungsprozess, die Bauteilprüfung sowie den Transfer der Ergebnisse in die Industrie durch serientaugliche Demonstratoren. Der Fokus der Arbeiten ist, die Fertigung auch im Umfeld eines für großskalige Stahlstrukturen üblichen hohen Individualisierungsgrades schweißtechnisch zu automatisieren und das Leichtbaupotenzial gezielt umzusetzen. Die Vorgaben aus der Designphase hinsichtlich einer lastgerechten Gestaltung bzw. Implementierung bionischer Ansätze können so gezielt durch einen adaptiven, automatisierten Schweißprozess eingestellt werden. Dies führt zu einer Erhöhung der Ermüdungs¬festigkeit und damit Produktlebensdauer, wodurch die Strukturen dünnwandiger ausgeführt und Ressourcen sowie CO2 eingespart werden können. 2022 9. Forum Leichtbau - Fortschrittliche Fertigungstechnologien und Werkstoffe für den Klimaschutz Berlin, Germany 29.09.2022 2022-12-21 OPUS4-56656 Vortrag Pittner, Andreas; Winterkorn, René; Fabry, Cagtay; Rethmeier, Michael; Ratkovac, Mirjana; Thiele, Marc; Baeßler, Matthias Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau Ziel des Verbundvorhabens „SmartWeld" ist es, für die schweißtechnische Fertigung von Stahlbaustrukturen exemplarisch am Beispiel von Hohlprofilknoten, welche als designrelevante Elemente von Gründungsstrukturen für Offshore-Windenergieanlagen (OWEA) einsetzbar sind, die Möglichkeiten des Leichtbaus unter konsequenter Digitalisierung der Fertigungskette aufzuzeigen, um einerseits die Ressourceneffizienz zu forcieren und gleichzeitig wettbewerbsfähige Fertigungsstrategien aufzuzeigen. Innerhalb von „SmartWeld" werden daher die Möglichkeiten einer wirtschaftlichen Fertigung von Leichtbau-Gründungsstrukturen am Beispiel aufgelöster Tragstrukturen (Jackets) aufgezeigt. Eine lastgerechte Auslegung der Schweißverbindungen nach bionischen Prinzipien ermöglicht, weitere Einsparpotenziale an Ressourcen bei gleichzeitiger Erhöhung der Lebensdauer zu erschließen. Die Ausnutzung konstruktiver Prinzipien des Leichtbaus zur Erzeugung innovativer und ressourcenschonender Produkte erfordert den Einsatz digitaler Werkzeuge in der Designphase, der virtuellen Absicherung, der Fertigung und Qualitätsüberwachung sowie nachgelagerten Bauteilprüfung zur Abbildung der Nutzungsphase. Im Rahmen der Arbeiten wird daher der gesamte Produktentstehungs- und Prüfprozess betrachtet. Dies beinhaltet das Design im Kontext des konstruktiven Leichtbaus, den schweißtechnischen Fertigungsprozess, die Bauteilprüfung sowie den Transfer der Ergebnisse in die Industrie durch serientaugliche Demonstratoren. Der Fokus der Arbeiten ist, die Fertigung auch im Umfeld eines für großskalige Stahlstrukturen üblichen hohen Individualisierungsgrades schweißtechnisch zu automatisieren und das Leichtbaupotenzial gezielt umzusetzen. Die Vorgaben aus der Designphase hinsichtlich einer lastgerechten Gestaltung bzw. Implementierung bionischer Ansätze können so gezielt durch einen adaptiven, automatisierten Schweißprozess eingestellt werden. Dies führt zu einer Erhöhung der Ermüdungs¬festigkeit und damit Produktlebensdauer, wodurch die Strukturen dünnwandiger ausgeführt und Ressourcen sowie CO2 eingespart werden können. 2022 Sitzung des DVS Fachausschuss FA03 - Lichtbogenschweißen Rostock, Germany 11.10.2022 2022-12-21 OPUS4-56657 Vortrag Pittner, Andreas; Winterkorn, René; Fabry, Cagtay; Rethmeier, Michael; Ratkovac, Mirjana; Thiele, Marc; Baeßler, Matthias Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau Offshore wind energy plays an important role for the desired transition towards a carbon dioxide free industry within the next decades. However, the grounding of the offshore wind plants governs the overall installation process besides bureaucratic bottlenecks. The application of lightweight principles in steel construction, e.g. the usage dissolved load-bearing structures, so called Jackets foundations, offer great potential in reducing the resource consumption, especially with respect to the needed amount of steel. In this context this presentation focuses on a fully digitalization of the welding manufacturing and as well as testing chain to enable a fully automated manufacturing as well as quality assessment of tubular nodes as key element of Jackets foundation structures. Furthermore, the relationship between the seam shape geometry and resulting fatigue strength is evaluated by numerical methods incorporating bionic principles. It is shown that tubular nodes can be welded fully automatically taking geometry tolerances into account. Moreover, the seam shape could be manufactured as requested by the numerical models which offers great potential for an extended lifetime. Subsequently, the improvements in resource efficiency and reduction of carbon dioxide emissions are evaluated by a life-cycle-assessment. 2022 Leichtbau in der Hauptstadtregion - Rohstoffe - Recycling - Rohstoffe: Kreislaufwirtschaft im Leichtbau Berlin, Germany 28.11.2022 2022-12-21