TY - GEN A1 - Habel, Wolfgang A1 - Hofmann, Detlef A1 - Gutmann, Toivo A1 - Basedau, Frank A1 - Molter, M. A1 - Hegger, J. ED - Inaudi, D. T1 - Characterization of bond performance of textiles in cement matrices using fiber optic sensors T2 - Smart structures and materials 2002 - Smart sensor technology and measurement systems CY - San Diego, CA, USA DA - 2002-03-18 KW - Textile reinforced concrete KW - Fibers KW - Concrete KW - Bond KW - Fiber-optic sensors PY - 2002 SN - 0-8194-4442-1 DO - https://doi.org/10.1117/12.472626 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4694 SP - 253 EP - 258 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-1458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hofmann, Detlef A1 - Habel, Wolfgang A1 - Gutmann, Toivo A1 - Basedau, Frank A1 - Molter, M. A1 - Hegger, J. A1 - Will, N. T1 - Untersuchungen an textilbewehrtem Beton PY - 2002 SN - 0025-5300 VL - 44 IS - 5 SP - 194 EP - 198 PB - Carl Hanser Verlag CY - München AN - OPUS4-1474 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Habel, Wolfgang A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Barner, Andreas A1 - Crail, S. A1 - Reichel, D. A1 - Schreiner, U. A1 - Lindner, E. T1 - Static and dynamic measurements on a newly developed precast concrete track for high speed railway traffic using embedded fiber-optic sensors T2 - International Conference on Force, Mass, Torque, Hardness and Civil Engineering Metrology in the Age Globalization CY - Celle, Germany DA - 2002-09-24 KW - Railway track system KW - Bonding behaviour KW - Fibre-optic sensor KW - Concrete composites PY - 2002 SN - 3-18-091685-0 SN - 0083-5560 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte IS - 1685 SP - 147 EP - 152 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-1755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reichel, D. A1 - Schreiner, U. A1 - Lindner, E. A1 - Habel, Wolfgang A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Barner, Daniel ED - Mencík, J. T1 - Strain Monitoring of a High Speed Railway Track Using Embedded Fibre-Optic Sensors T2 - First International Conference Reliability and Diagnostics of Transport Structures and Means CY - Pardubice, Czech Republic DA - 2002-09-26 PY - 2002 SN - 9788071944645 PB - Univ. CY - Pardubice AN - OPUS4-1725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüsken, Götz A1 - Shamsuddoha, Md A1 - Pirskawetz, Stephan A1 - Hofmann, Detlef A1 - Baeßler, Matthias A1 - Kühne, Hans-Carsten T1 - Potential of a Repair System for Grouted Connections in Offshore Structures: Development and Experimental Verification N2 - Grouted connections are intensively used in offshore rigs, platforms as well as jacket and monopile offshore wind turbine structures. Being located in remote offshore conditions, these connections can experience considerable adverse loading during their lifetimes. Degradation was reported inside similar connections, which were installed in the last three decades. Grouting in the offshore sites may often be proven difficult, which eventually leads to reduced load-bearing 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 this study, scaled grouted connections were manufactured using a novel mould, whose integrity were monitored using digital image correlation (DIC). The connections were loaded under static load to visualize the main failure pattern using distributed fibre optic sensors and acoustic emission (AE) analysis. Grouted connections were then repaired using a cementitious injectable grout. The effectiveness of the grout injection was monitored using dye penetration technique. Finally, specimens are reloaded to identify the potential of such repair for grouted connections. KW - Offshore KW - Grouted connection KW - Fibre optic sensors KW - Acoustic emission analysis KW - Cracks KW - Repair KW - Rehabilitation KW - Static loading PY - 2021 DO - https://doi.org/10.1016/j.marstruc.2021.102934 VL - 77 SP - 102934 PB - Elsevier Ltd. AN - OPUS4-52059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Pötschke, Samuel A1 - Breithaupt, Mathias T1 - Funktionsprinzip faseroptischer Sensoren N2 - Das Poster präsentiert die Grundlagen zur Funktionsweise optischer Fasern bzw. faseroptischer Sensoren, die im Rahmen eines Feldversuchs zum Einsatz kommen. T2 - Tag der offenen Tür auf dem Testgelände der BAM (BAM TTS) CY - Horstwalde, Germany DA - 29.09.2018 KW - Faseroptische Sensorik KW - Verteilte Messverfahren KW - Quasi-verteilte Messverfahren PY - 2018 AN - OPUS4-46333 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilder, Constanze A1 - Kohlhoff, Harald A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Habel, Wolfgang A1 - Baeßler, Matthias A1 - Niederleithinger, Ernst A1 - Georgi, Steven A1 - Herten, M. ED - Jaroszewicz, L.R. T1 - Static and dynamic pile testing of reinforced concrete piles with structure integrated fibre optic strain sensors N2 - Static and dynamic pile tests are carried out to determine the load bearing capacity and the quality of reinforced concrete piles. As part of a round robin test to evaluate dynamic load tests, structure integrated fibre optic strain sensors were used to receive more detailed information about the strains along the pile length compared to conventional measurements at the pile head. This paper shows the instrumentation of the pile with extrinsic Fabry-Perot interferometers sensors and fibre Bragg gratings sensors together with the results of the conducted static load test as well as the dynamic load Tests and pile integrity tests. T2 - EWOFS 2013 - 5th European workshop on optical fibre sensors CY - Kraków, Poland DA - 19.05.2013 KW - Static load test KW - Dynamic load test KW - Pile integrity test KW - Extrinsic Fabry-Perot interferometer KW - Fibre Bragg grating KW - Structure integrated sensor KW - Fibre optic strain sensor PY - 2013 SN - 978-0-81949-634-8 DO - https://doi.org/10.1117/12.2026813 SN - 0277-786X N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE VL - 8794 IS - Paper 8794 - 181 SP - 700 EP - 703 AN - OPUS4-28854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lay, Vera A1 - Baensch, Franziska A1 - Johann, Sergej A1 - Sturm, Patrick A1 - Mielentz, Frank A1 - Prabhakara, Prathik A1 - Hofmann, Detlef A1 - Niederleithinger, Ernst A1 - Kühne, Hans-Carsten T1 - SealWasteSafe: materials technology, monitoring techniques, and quality assurance for safe sealing structures in underground repositories N2 - Within the project SealWasteSafe, we advance construction materials and monitoring concepts of sealing structures applied for underground disposal of nuclear or toxic waste. As these engineered barriers have high demands concerning integrity, an innovative alkali-activated material (AAM) is improved and tested on various laboratory scales. This AAM has low reaction kinetics related to a preferential slow release of the heat of reaction in comparison to alternative salt concretes based on Portland cement or magnesium oxychloride cements. Hence, crack formation due to thermally induced strain is reduced. After successful laboratory scale analysis (Sturm et al., 2021), the AAM is characterised on a larger scale by manufacturing test specimens (100–300 L). Conventional salt concrete (DBE, 2004) and the newly developed AAM are compared using two specimen geometries, i.e. cylindrical and cuboid. A comprehensive multisensor monitoring scheme is developed to compare the setting process of AAM and salt concrete for these manufactured specimens. The analysed parameters include temperature and humidity of the material, acoustic emissions, and strain variations. Passive sensor systems based on radiofrequency identification technology (RFID) embedded in the concrete, enable wireless access to temperature and humidity measurements and are compared to conventional cabled systems. Additionally, fibre-optic sensors (FOS) are embedded to record strain, but also have potential to record temperature and moisture conditions. Part of this project aims at demonstrating the high reliability of sensors and also their resistance to highly alkaline environments and to water intrusion along cables or at sensor locations. Further technical improvements were implemented so that first results clearly show the scalability of the setting process from previous small-scale AAM experiments and particularly the high potential of the newly developed approaches. Furthermore, ultrasonic methods are used for quality assurance to detect obstacles, potential cracks and delamination. On the one hand, both active and passive ultrasonic measurements complement the results obtained from the multisensor monitoring scheme for the produced specimens. On the other hand, the unique large aperture ultrasonic system (LAUS) provides great depth penetration (up to nearly 10 m) and can thus be applied at in situ sealing structures built as a test site in Morsleben by the Federal Company for Radioactive Waste Disposal (Bundesgesellschaft für Endlagerung, BGE) as shown by Effner et al. (2021). An optimised field lay-out identified from forward modelling studies and advanced imaging techniques applied to the measured data will further improve the obtained results. To characterise the inside of the test engineered barrier and achieve a proof-of-concept, an ultrasonic borehole probe is developed to enable phased arrays that can further improve the detection of potential cracks. Modelling results and first analysis of semispherical specimens confirmed the reliability of the directional response caused by the phased arrays of the newly constructed ultrasonic borehole probe. Overall, the project SealWasteSafe improves the construction material, multisensor monitoring concepts and ultrasonics for quality assurance. This will help to develop safe sealing structures for nuclear waste disposal. The outcomes are particularly valuable for salt as a host rock but partly also transferrable to alternative conditions. T2 - Safe ND Interdisciplinary research symposium on the safety of nuclear disposal practices CY - Berlin, Germany DA - 10.11.2021 KW - Borehole probe KW - SealWasteSafe KW - Engineered barrier KW - Materials technology KW - Monitoring KW - AAM KW - Ultrasound PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539172 DO - https://doi.org/10.5194/sand-1-127-2021 VL - 1 SP - 127 EP - 128 PB - Copernicus AN - OPUS4-53917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lay, Vera A1 - Mielentz, Frank A1 - Prabhakara, Prathik A1 - Baensch, Franziska A1 - Johann, Sergej A1 - Hofmann, Detlef A1 - Sturm, Patrick A1 - Stamm, Michael A1 - Niederleithinger, Ernst T1 - Multi-sensory monitoring and ultrasound for quality assurance at underground sealing structures N2 - Within the safety concepts of underground disposal sites of nuclear waste, engineered barriers play an important role. As these sealing structures have high demands concerning integrity, we aim at advancing the available construction materials, monitoring, and inspection techniques within the project SealWasteSafe. A specifically developed alkali-activated material is compared to classical salt concrete. A comprehensive multi-sensory monitoring scheme is used at 150-340 l specimens to monitor setting and hardening of both materials. All sensors are demonstrated to resist the highly alkaline environments. Besides cabled and wireless temperature and humidity of the materials, strain variations using fibre optic sensors and acoustic emissions are recorded over periods of at least 28 days, partly for more than eight months. After hardening of the specimens, further nondestructive evaluations using ultrasonic echo and thermographic measurements are conducted. Preliminary results proof the suitability of the tested sensors and clearly highlight differences between the tested materials. Particularly, the newly developed alkali-activated material shows lower acoustic emission activity indicating less cracking activity. Additionally, unique ultrasonic methods will enable better images of potential internal objects and cracks at in-situ sealing structures. A largescale ultrasonic system is optimised to reliably detect objects at a depth exceeding 9 m while still obtaining a good resolution. Modelling studies show the potential of further increasing the distance between individual transducer arrays. Additionally, a new ultrasonic borehole probe using phased arrays allowing for beam focussing is constructed and tested. Laboratory measurements at a halfcylindrical concrete specimen coincide well with the previous modelling. In total, the presented safe materials, detailed monitoring approaches and ultrasonic quality assurance methods will help to obtain safe sealing structures within salt as a host rock. The concepts can partly be transferred to sealing structures in alternative host rocks and will also be valuable for non-nuclear waste repositories. T2 - NDE NucCon CY - Espoo, Finland DA - 25.01.2023 KW - SealWasteSafe KW - Engineered barriers KW - Monitoring KW - Embedded sensors KW - Ultrasonic imaging PY - 2023 SP - 2 EP - 10 AN - OPUS4-56928 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habel, Wolfgang A1 - Hofmann, Detlef A1 - Basedau, Frank T1 - Rückwirkungsarme faseroptische Dehnungssensoren für weiche Materialien und Verbundwerkstoffe T2 - GESA-Symposium 1999 CY - Warnemünde, Deutschland DA - 1999-05-06 KW - Faseroptische Dehnungssensoren PY - 1999 SN - 3-18-091463-7 SN - 0083-5560 N1 - Sprachen: Deutsch/Englisch - Languages: German/English SP - 103 EP - 112 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-790 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -