TY - CONF A1 - Skłodowska, Anna A1 - Lay, Vera A1 - Baensch, Franziska A1 - Niederleithinger, Ernst A1 - Kühne, Hans-Carsten T1 - Microseismicity monitoring in materials for nuclear waste storage repositories N2 - One of the major tasks in nuclear waste management is to design safe and reliable sealing structures for radioactive waste repositories. Particularly for salt as a host rock, engineered barrier systems for underground waste disposal must be constructed of well-understood (cementitious) materials that will sustain environmental conditions and ensure high durability. Within the SealWasteSafe project, we studied two materials with a potential for sealing structures for nuclear waste repositories: an innovative alkali-activated material (AAM) and standard salt concrete (SC). To analyze the development of microstructural changes within the materials, we monitored microseismicity (aka acoustic emission monitoring) occurring during the hardening and setting period in two 340-liter-cubic specimens for up to ~250 days. The monitoring results showed, that in the first 61 days, fewer events occurred in AAM compared to SC. After this time the number of events in AAM sharply increased and significantly exceeded those observed in SC. However, the source localization analysis revealed that the increase of microseismicity in AAM material was not related to the formation of macro-cracks within the material but was mainly caused by the surface effects. Accompanying analysis of the test specimens with additional methods (such as e.g., X-ray CT) proved that no macro-cracks were observed inside the AAM specimen. Further analysis in the time and frequency domains helped to characterize the tested materials and to estimate their potential to be used for engineered barriers in nuclear waste repositories. Overall, our study shows the potential of microseismicity monitoring for feasibility studies and quality assurance in a broad range of applications, also in structural health monitoring. T2 - 84. Jahrestagung der Deutschen Geophysikalischen Gesellschaft CY - Jena, Germany DA - 10.03.2024 KW - Microseismicity KW - Nuclear waste repositories KW - Acoustic emission KW - SealWasteSafe project KW - Salt rock KW - Alkali-activated materia PY - 2024 AN - OPUS4-60549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Muon tomography - ready for practical application? N2 - Security and nuclear safeguards, but not yet in civil engineering. The potential is enormous, as muon tomography could replace traditional X-ray imaging of infrastructure, a method that was popular in the past but has mostly been abandoned due to concerns about radiation safety. In 2020, a report on the first large-scale muon tomography experiment on a reinforced concrete specimen was published. However, robust mobile detectors and faster data acquisition methods are still needed. This is now changing, however. Prototype mobile detectors have been announced or are in development, and data acquisition time has been reduced from weeks to days. This presentation will showcase current developments and focus on a validation experiment at BAM. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Türkiye DA - 24.09.2055 KW - Muon tomography KW - Bridge inspection KW - Concrete PY - 2025 AN - OPUS4-64256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - ZfP-Bau post Carolabrücke: Chancen und Herausforderungen N2 - Der Einsturz der Carolabrücke hat die Fachwelt, Politik und Öffentlichkeit aufgerüttelt. Während die Diagnose der Ursachen noch andauert (aber wohl zum Vortragzeitpunkt abgeschlossen sein wird), werden erste, nach Ansicht vieler Experten überfällige Konsequenzen gezogen. Zahlreiche Brücken werden vorsichtshalber gesperrt, intensive Prüfungen und Überwachungsmaßnahmen sind veranlasst und werden ausgeweitet. Die Untersuchungsmethodik für Brücken mit dem Verdacht auf Spannungsrisskorrosion und ohne „sicheres“ Ankündigungsverhalten vor Versagen – übrigens keineswegs auf die östlichen Bundesländer beschränkt – steht auf dem Prüfstand. Dabei erhält wohl auch die zerstörungsfreie Prüfung eine veränderte und wichtige Rolle, ebenso wie Methoden zur Dauerüberwachung. Dabei wird aus gutem Grund auf den Stand der Technik zurückgegriffen. Der Vortrag beleuchtet die Rolle der ZfP und die verwendeten Methoden im Rahmen dieser Untersuchungen. Er weist aber auch auf Technologien hin, die in den nächsten Jahren in die Praxis eingeführt werden dürften und zukünftig bei der Untersuchung und Überwachung von Stahl- und Spannbetonbauwerken eine Rolle spielen dürften. T2 - DGZfP Jahrestagung CY - Berlin, Germany DA - 26.05.2025 KW - Zerstörungsfreie Prüfung KW - ZfPBau KW - Brücken KW - Stahlbeton PY - 2025 AN - OPUS4-63230 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - NDT-CE Qualification and Certification N2 - Due to the increased demand for NDT investigations and assessment of energy and traffic infrastructure, a qualification and certification system for NDT personel is urgently needed. Up to now, only Italy, Malaysia and Germany have set up such systems. The talk gives an overview of the demand and current activities, including those of IAEA. T2 - IAEA ICARST 2025 CY - Vienna, Austria DA - 07.04.2025 KW - NDT-CE KW - Qualification KW - Certification PY - 2025 AN - OPUS4-63002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Condition monitoring for lifetime extension of interim storage facilities N2 - The German interim nuclear storage facilities are designed for a 50 year service life and 40-year operating period. They will be needed much longer, as a final repository will not be available until 2050 at the earliest. The objective of ZuMoBau-ZL is to develop a suitable condition assessment and monitoring concept suitable for the structures in interim storage facilities, including life prediction models, with which the remaining service life can be predicted, verified, and monitored as realistically as possible. T2 - IAEA ICARST 2025 CY - Vienna, Austria DA - 07.04.2025 KW - Nuclear waste KW - Interim storage KW - Liefetime extension KW - Reinforced concrete PY - 2025 AN - OPUS4-62984 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skłodowska, Anna A1 - Coronel Subia, Hernan Alejandro A1 - Inzunza Araya, Ernesto A1 - Niederleithinger, Ernst T1 - Influence of velocity changes on acoustic emission monitoring of masonry walls under diagonal compression load N2 - Acoustic emission (AE) is a highly sensitive, non-destructive method which has great potential in damage event detection and assessment in masonry structures exposed to e.g., seismic loads. However, the highly heterogenous nature of the masonry structures and their low densities cause high attenuation and distortion of the signal. Localization of the AE events is challenging because the AE waves propagate through various masonry constituents (i.e., bricks and mortar joints) at different velocities. We present an attempt to locate the sources of AE events from the signals recorded during the diagonal compression loading, and analyze the influence of different wave velocities on its accuracy. T2 - 36th Conference of the European Working Group on Acoustic Emission CY - Potsdam, Germany DA - 18.09.2024 KW - Acoustic emission KW - Masonry KW - Compression test PY - 2024 AN - OPUS4-61689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertola, Numa A1 - Schumacher, Thomas A1 - Niederleithinger, Ernst A1 - Brühwiler, Eugen T1 - Combining passive and active ultrasonic stress wave monitoring for the characterization of the early-age properties of a UHPFRC beam N2 - This article focuses on the characterization of the early-age properties of Ultra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC), which is becoming popular for designing lightweight and durable structures. Due to the large proportion of cement in the mix, the hardening of UHPFRC is significantly faster than conventional concrete. Therefore, the development of UHPFRC properties, such as the elastic modulus, is difficult to monitor as it happens while elements are within the formwork. For this reason, the hydration process of UHPFRC elements is not fully understood yet. A combined passive (or acoustic emission) and active ultrasonic stress wave monitoring approach has the potential to characterize structures made of cementitious materials over their entire service duration. Using a network of embedded ultrasonic transducers, monitoring can start only a few instants after casting. A UHPFRC beam with a T-shaped cross-section and a length of 4.2 m was constructed and instrumented with 24 transducers as well as 15 thermocouples. Monitoring results lead to the characterization of the development of the early-age UHPFRC properties on the structural-element scale while the specimen is within the formwork. The continuous monitoring approach enabled accurate estimations of the spatial and temporal evolution of the modulus of elasticity. Thanks to this novel combination of monitoring techniques, the early age properties of UHPFRC, which were measured at the material scale, are confirmed at the structural scale for the first time. KW - Concrete KW - UHPFRC KW - Acoustic emission KW - Ultrasonic monitoring KW - Coda wave interferometry PY - 2025 DO - https://doi.org/10.1016/j.conbuildmat.2025.140319 SN - 0950-0618 VL - 466 SP - 1 EP - 18 PB - Elsevier Ltd. AN - OPUS4-63448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Applications of a Multi-Channel Ultrasound System for Assessing Large Concrete Structures N2 - Non-destructive testing (NDT) plays a vital role in the assessment of large concrete structures, where the detection of internal defects is particularly challenging due to size, material heterogeneity and complex geometries. In this study, the use of a multi-channel, large-aperture ultrasound system is demonstrated for improving the ultrasonic pulse-echo method for evaluating these large structures. The large aperture of the ultrasound system allows for broader coverage and enhanced sensitivity to internal features such as cracks, voids, and embedded components within the concrete. By capturing data from multiple channels simultaneously, the system improves both resolution and depth penetration. A weighted sum of the Kirchhoff migration is used to post-process the data, resulting in better visualisation and a more detailed interpretation of the internal condition of the structure. This approach is particularly effective for thick and complex materials where conventional methods face limitations. In addition to the pulse-echo method, time-of-flight (TOF) tomography is used to provide quantitative analysis of internal structures. Time-picking techniques allow for the precise mapping of anomalies within the material, offering insights into the condition of concrete with varying geometries and compositions. Together, these two methods: pulse-echo imaging with the large-aperture multichannel system and TOF tomography imaging, offer different possibilities for assessing the internal condition of large concrete structures. The pulse-echo technique focuses on providing detailed images of structural defects, while the TOF tomography provides quantitative data on internal features. This combined approach offers a comprehensive and reliable method for the assessment of large infrastructures. T2 - ISNT NDE 2024 CY - Chennai, India DA - 12.12.2024 KW - NDT-CE KW - concrete KW - ultrasound KW - imaging KW - Kirchhoff KW - tomography PY - 2024 AN - OPUS4-62204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst A1 - Sein, Sander A1 - Kervalisvil, Andrei A1 - Wöstmann, Jens A1 - Helm, Marek T1 - Muon tomography - ready for practical application? N2 - Muon tomography uses naturally occurring nuclear particles to 'X-ray' technical objects. It has applications in security and nuclear safeguards, but not yet in civil engineering. The potential is enormous, as muon tomography could replace traditional X-ray imaging of infrastructure, a method that was popular in the past but has mostly been abandoned due to concerns about radiation safety. In 2020, a report on the first large-scale muon tomography experiment on a reinforced concrete specimen was published. However, robust mobile detectors and faster data acquisition methods are still needed. This is now changing, however. Prototype mobile detectors have been announced or are in development, and data acquisition time has been reduced from weeks to days. This presentation will showcase current developments and focus on a validation experiment at BAM. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Türkiye DA - 24.09.2025 KW - Concrete KW - Muon tomography KW - Inspection PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642517 DO - https://doi.org/10.58286/31696 SN - 1435-4934 VL - 30 IS - 10 SP - 1 EP - 10 PB - ndt.net AN - OPUS4-64251 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Ute A1 - Emge, Julia A1 - Klein, Samuel A1 - Oswald, Jan A1 - Shpakova, Nina A1 - Stopp, Philipp A1 - Weingard, Christoph A1 - Koster, Dirk A1 - Schönsee, Eric A1 - Hille, Frank A1 - Niederleithinger, Ernst T1 - Development of distributed sensor electronics for energy-efficient and proactive maintenance of buildings N2 - Permanently installed sensor systems are becoming increasingly important for monitoring critical infrastructure. The research institutes Fraunhofer IZFP and BAM, together with industrial partners and users, are developing a concept for an electronic system consisting of an Edge-Gateway as a central high-performance node and a variable number of Sensor-Edge units that establish the connection between the sensors of the permanent monitoring system and the gateway, which also provides connection to a cloud. A software tool allows identification and localization of sensors and visualization of sensor data. The principle of the system is demonstrated using sensors installed in the road surface to monitor traffic loads as an example. Two test structures, a full-scale laboratory at Fraunhofer IZFP, Saarbrücken, and the “BLEIB” reference structure at BAM, test site technical safety (TTS) Horstwalde, were used to demonstrate the principle and the functioning of the electronic system. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Türkiye DA - 24.09.2025 KW - Edge computing KW - Bridge monitoring KW - Multi-sensor PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642530 DO - https://doi.org/10.58286/31650 SN - 1435-4934 VL - 30 IS - 10 SP - 1 EP - 3 PB - ndt.net AN - OPUS4-64253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Roumia, N. A1 - Niederleithinger, Ernst A1 - Mazotti, C. T1 - Post-tensioned concrete inspection and imaging using 2D and 3D Dry Point Contact ultrasound array N2 - by the asset owners. Advancements were introduced to the method by distributing numerous shear horizontal Dry Point Contact (DPC) transducers in a uniform way, forming a linear array that allows for immediate two-dimensional imaging of the subsurface using Synthetic Aperture Focusing Technique (SAFT). Recent developments were implemented, allowing for the full potential use of the array by means of three-dimensionaldata acquisition instead of two-dimensional. This work provides a practical comparison between the 2D Linear scanning mode and the newly introduced 3D Matrix scanning mode regarding the tendon duct inspection, grouting quality, and reinforcement localization. Imaging the subsurface was performed through research-oriented software, namely InterSAFT, which allows for 2D and 3D imaging using Linear and Matrix data acquisitions. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Türkiye DA - 24.09.2025 KW - Ultrasound KW - Imaging KW - Concrete KW - SAFT PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642551 DO - https://doi.org/10.58286/31690 SN - 1435-4934 VL - 30 IS - 10 SP - 1 EP - 4 PB - ndt.net AN - OPUS4-64255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Emerging technologies for non destructive testing and monitoring of concrete structures in nuclear facilities N2 - For a long time, practical application of non-destructive testing in civil engineering has been limited on simple (but useful) methods such as rebound hammers, ultrasonic pulse velocity measurements, rebar detectors or potential mapping. Since the late 1990ies new methods and devices have been developed for geometry and damage detection, including radar and ultrasonic echo array techniques which brought progress in condition assessment of buildings and infrastructure assets. However, there are still gaps, especially for massive concrete structures used in nuclear facilities, including lack of penetration depth, resolution, or translation of NDT parameters to engineering properties. Recent research tries to fill these gaps. Currently, new ultrasonic devices with greater penetration depth and better resolution depth are developed, including imaging methods revealing greater details of the interior of concrete constructions. Ultrasonic technologies are also extended to nonlinear methods providing baseline free damage assessment and monitoring capabilities. Another example of a technique with a huge potential for concrete constructions is muon tomography, where first field experiments are underway. A review of the potential and limitations of these methods will be given in the presentation. T2 - IAEA ICARST 2025 CY - Vienna, Austria DA - 07.04.2025 KW - NDT-CE KW - Ultrasound KW - Muography KW - Concrete KW - Emerging PY - 2025 AN - OPUS4-63003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst T1 - Improvement and extension of the parallel seismic method for foundation depth measurement N2 - he parallel seismic (PS) method is used for determination of the unknown or undocumented depth of foundations, mostly piles. It was developed several decades ago and has not much changed since. PS is based on impulse generation on the pile head and registration of travel times in a borehole parallel to the foundation. The method is applicable to many foundation types, including single piles, pile walls, or sheet piles. While the accuracy is known to be high if the distance between foundation and borehole is small, the foundation length is overestimated with increasing distance. This paper presents the results of a systematic study on the influence of geometric and material parameters on the measurement resultsand explains the effects by studying the underlying wave phenomena based on numerical studies. It can be shown that several parameters (e.g. borehole inclination) have a strong influence. Foundation flaws and soil layers have also to be taken into account, while the possibilities in the other direction (derivation of soil parameters or detection of flaws from the results) are limited. Based on the simulation results, a new mathematical algorithm for data interpretation has been developed which takes into Account the soil layers and the borehole inclination. This novel data interpretation scheme was used in combination with different data Inversion methods. The new interpretation method was successfully validated using several sets of simulated data. Not only was it shown to be more accurate than all other available methods, but it also extended the maximum allowable pile–borehole distance to 2–3 m. Today, parallel seismics is the only method applicable on both metallic and non-metallic foundations which can be used without calibration. It has the largest range of all borehole methods. To enhance its efficiency it can be combined with downhole seismic measurements in the very same borehole to retrieve soil parameters. KW - Parallel seismic KW - Length KW - Piles KW - Interpretation KW - Foundations PY - 2012 DO - https://doi.org/10.1016/j.sandf.2012.11.023 SN - 0038-0806 VL - 52 IS - 6 SP - 1093 EP - 1101 PB - Soc. CY - Tokyo AN - OPUS4-27908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grohmann, Maria A1 - Niederleithinger, Ernst T1 - Application of Elastic Reverse Time Migration to Ultrasonic Echo Data from Concrete Structures N2 - To enhance ultrasonic imaging of concrete structures, we adapted the geophysical migration method, Reverse Time Migration (RTM), for non-destructive testing (NDT) in civil engineering. First, two 2D elastic RTM algorithms, each considering different wave types, were implemented and evaluated with synthetic ultrasonic data. The algorithm that best resolved numerical concrete structures was subsequently applied to real ultrasonic data from a concrete specimen. Compared with conventional synthetic aperture focusing technique (SAFT) imaging, elastic RTM reproduced a greater number of structural features in both the numerical model and the concrete specimen. In particular, elastic RTM reconstructed vertical interfaces as well as hidden lower edges of modeled cavities and tendon ducts. Notably, imaging the full cross-sections of tendon ducts, which enables direct diameter estimation, represents a novel achievement for ultrasonic NDT. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Turkey DA - 24.09.2025 KW - Concrete Structures KW - Ultrasonic Echo Technique KW - Ultrasonic Imaging KW - Elastic Reverse Time Migration KW - Synthetic Aperture Focusing Technique PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650350 DO - https://doi.org/10.58286/31680 SN - 1435-4934 SP - 1 EP - 3 PB - e-Journal of Nondestructive Testing CY - www.ndt.net AN - OPUS4-65035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Giese, Lutz A1 - Weritz, Friederike A1 - Weimann, Karin A1 - Niederleithinger, Ernst A1 - Ulbricht, J.P. ED - Dincer, I. T1 - Bricks made of sludge from the Izmir bay - an integrative approach for the recycling of sludge - preliminary results T2 - 1st International Exergy, Energy and Environment Symposium ; IEEES-1 CY - Izmir, Turkey DA - 2003-07-13 PY - 2003 SN - 975-288440-7 SP - 995 EP - 1003 CY - Izmir AN - OPUS4-2829 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epple, Niklas A1 - Sanchez Trujillo, Camila Andrea A1 - Hau, Julia A1 - Niederleithinger, Ernst A1 - Malm, F. T1 - Structural Monitoring in an Urban Underground Metro Station Using Cod N2 - Active ultrasonic monitoring with coda wave interferometry has demonstrated its potential for structural Health monitoring in concrete structures. This study investigates its application using ultrasonic transducers embedded in the ceiling of a subway station in Munich, Germany. We evaluate the impact of environmental conditions, specifically electromagnetic interference and temperature, on data quality, as well as the influence of regular loading from passing trams. Results indicate that electromagnetic interference significantly affects measurements, while temperature effects remain minimal due to the station’s stable thermal environment. Long-term measurements and a controlled load test show that both dynamic and static loading from trams induce ultrasonic velocity changes of only 0.01%–0.06%. Although the experiment demonstrates the capacity to detect structural responses and supports the feasibility of long-term monitoring, improved electromagnetic shielding and Hardware reliability are required for successful future applications. T2 - NDT-CE 2025 CY - Izmir, Turkey DA - 24.09.2025 KW - Coda Wave Interferometry (CWI) KW - Structural health monitoring (SHM) KW - Concrete KW - Ultrasonic testing KW - Urban infrastructure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654619 DO - https://doi.org/10.58286/31706 SN - 1435-4934 SP - 1 EP - 10 PB - e-Journal of Nondestructive Testing (eJNDT) AN - OPUS4-65461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst ED - Matsumoto, T T1 - The parallel seismic method for foundation length measurement: useful also to check pile integrity? N2 - The Parallel Seismic (PS) method is used for the determination of the unknown or undocumented depth/length of foundations, mostly piles. The method was developed some decades ago and has recently been improved by more accurate Interpretation methods. Some authors claim that the PS method might also be useful for checking the integrity of piles. The examples presented are based on rather big flaws. Numerical studies have been carried out with more realistic geometries. A finite integration technique involving cylinder symmetry (CEFIT) was used. Necks and bulges of various sizes have been simulated and the results have been compiled. It can be seen that the PS results are in fact influenced by pile irregularities. But in reality these effects are at least partly superposed by other influences or may be mistaken for effects caused by soil layering. However, the PS results and any deviation of travel time curves from a “normal” shape can be used as a hint to perform detailed studies involving other methods. T2 - 9th International conference on testing and design methods for deep foundations CY - Kanazawa, Japan DA - 18.09.2012 KW - Parallel seismic KW - Bored piles KW - Integrity KW - Low strain testing PY - 2012 SN - 978-4-89010-597-7 SP - 217 EP - 222 AN - OPUS4-27336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst A1 - Hübner, M. A1 - Müller, H. A1 - Kauther, R. T1 - Qualitätssicherung überschnittener Bohrpfahlwände mit der Ultraschallmethode am Beispiel der Schleuse Dörverden N2 - Überschnittene Bohrpfahlwände sind eine bewährte Konstruktionsmethode zur Herstellung tragender, hydraulisch dichter, tiefreichender Wände im Spezialtiefbau. Anders als bei Einzelpfählen gibt es bisher für die zerstörungsfreie Prüfung von Pfahlwänden keine etablierte Vorgehensweise. Erste Versuche an Baustellen und Modellkörpern zeigten das Potential der Ultraschallmethode (cross-hole sonic logging) zur Prüfung der Fugen über mehrere Pfähle hinweg. An der Schleusenbaustelle Dörverden ergab sich die Möglichkeit, das Verfahren unter Realbedingungen einzusetzen und die Ergebnisse visuell durch Kernbohrungen und nach Aushub zu evaluieren. Dabei wurden die meisten der prognostizierten Fehlstellen bestätigt. Die Resultate wurden in einer Neuauflage der entsprechenden Regelwerke berücksichtigt. T2 - Fachtagung Bauwerksdiagnose 2012 - Praktische Anwendungen zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Germany DA - 23.02.2012 KW - Bohrpfahlwand KW - Ultraschallmethode PY - 2012 UR - http://www.bauwerksdiagnose2012.de/Portals/bwd2012/Dokumente/bb/v17.pdf SN - 978-3-940283-40-5 IS - Vortrag 17 SP - 1 EP - 11 CY - Berlin AN - OPUS4-27337 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Wunderlich, Carolin ED - Meßinger, J. T1 - Temperature influence on ultrasonic velocity in concrete N2 - Ultrasonic methods are valuable tools for quality assessment and structural imaging of concrete. In such applications, accurate and reliable determination of ultrasonic wave velocities is essential, as they are affected by various experimental and environmental factors. In this research coda wave interferometry (CWI) was used to determine the influence of temperature (0 to 50 °C) on ultrasonic wave velocity in concrete samples. A resolution of better than 10-4 was achieved in the measurement of relative velocity changes. Reversibility and repeatability were taken into account. In additlon the benefit of newly developed permanently embedded sensors was evaluated. The presented results can be used to Interpret and refine data from ultrasonic monitoring Systems. T2 - 2nd Neustadt workshop CY - Neustadt a.d. Weinstraße DA - 11.11.2012 KW - Coda wave interferometry KW - Concrete KW - Temperature KW - Ultrasound KW - Velocity PY - 2012 SN - 0947-1944 VL - IV SP - 60 EP - 61 PB - Dt. Geophysikalische Ges. CY - Potsdam AN - OPUS4-27224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Sabine A1 - Niederleithinger, Ernst A1 - Bohlen, T. T1 - Reverse time migration: a seismic imaging technique applied to synthetic ultrasonic data N2 - Ultrasonic echo testing is a more and more frequently used technique in civil engineering to investigate concrete building elements, to measure thickness as well as to locate and characterise built-in components or inhomogeneities. Currently the Synthetic Aperture Focusing Technique (SAFT), which is closely related to Kirchhoff migration, is used in most cases for imaging. However, this method is known to have difficulties to image steeply dipping interfaces as well as lower boundaries of tubes, voids or similar objects. We have transferred a processing technique from geophysics, the Reverse Time Migration (RTM) method, to improve the imaging of complicated geometries. By using the information from wide angle reflections as well as from multiple events there are fewer limitations compared to SAFT. As a drawback the required computing power is significantly higher compared to the techniques currently used. Synthetic experiments have been performed on polyamide and concrete specimens to show the improvements compared to SAFT. We have been able to image vertical interfaces of step-like structures as well as the lower boundaries of circular objects. It has been shown that RTM is a step forward for ultrasonic testing in civil engineering. KW - Beton KW - Ultraschall KW - Concrete KW - Imaging KW - Ultrasonics KW - Reverse time migration PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-262952 DO - https://doi.org/10.1155/2012/128465 SN - 1687-8868 SN - 1687-885X VL - 2012 IS - Article ID 128465 SP - 1 EP - 7 PB - Hindawi Publishing Corporation CY - New York, NY, USA AN - OPUS4-26295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Ultrasonic methods for quality assurance and condition assessment in nuclear concrete structures – lessons learned N2 - Ultrasonic non-destructive testing methods have found various applications in quality assurance and condition assessment of nuclear concrete structures. This includes but is not limited to the localization of construction features (thickness measurements, reinforcement, tendon ducts, and others) and damage detection (e. g. corrosion or cracks). However, there are still limitations, e. g. limited penetration depth and resolution, issues when testing hybrid steel/concrete structures as well as absence of standards and regulations. This presentation will show progress in some of these issues and will focus on advanced instrumentation and validation of ultrasonic NDT for concrete structures. Ultrasonic echo testing has been limited to a penetration depth of less than one meter in reinforced concrete. The development of the LAUS (Large Aperture Ultrasonic System), using a large array of ultrasonic transducers and wider offsets between transmitter and receiver, allows to reach up to 5 m in reinforced concrete and 9 m in unreinforced concrete. This capability has been demonstrated by collecting data from an engineered salt concrete barrier in an underground nuclear waste storage facility. Due to an increasingly competitive environment, commercial manufacturers will continue to develop equipment with enhanced penetration and/or increased resolution. To quantify the capabilities and reliability of ultrasonic tests, validation mockups with engineered flaws are required. EPRI and BAM have built a large-scale mockup at a test site close to Berlin (BAM-TTS, Horstwalde) using a design which is repeated at other places. This presentation will also cover the methods deployed on engineered flaws and the repeatability of the test results. T2 - NDE in Nuclear CY - Charlotte, NC, USA DA - 25.7.2019 KW - Concrete KW - Nuclear Structures KW - Ultrasound PY - 2019 AN - OPUS4-48690 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - NDE of foundations N2 - This talk teaches the basic princioles and applications of NDT methods for deep foundations, sprecifically piles. A variety of testing methods are discussed (integrity testing, ultrasonic crosshole logging, parallel seismic and others). Capabilities and limitations are given as well as specific hints for practical use. T2 - NDE 2019 Pre-Conference Tutorial PCT 4 CY - Bangalore, India DA - 03.12.2019 KW - NDT KW - Foundation KW - Pile KW - Integrity testing PY - 2019 AN - OPUS4-50169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Recent advances in NDE of concrete structures at BAM N2 - This talk gives an introduction to BAM and its NDT-CE division. Specific challenges in NDT-CE are discussed as well as recent research results. T2 - NDE 2019 Pre-Conference Tutorial PCT 4 CY - Bangalore, India DA - 03.12.2019 KW - NDT KW - Civil engineering PY - 2019 AN - OPUS4-50168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -