TY - JOUR A1 - Kind, Thomas A1 - Wöstmann, Jens A1 - Feistkorn, Sascha A1 - Trela, Christiane ED - Meßinger, Jens T1 - Radar in der Baupraxis: Lokalisierung von zweilagig vorgespannter Bewehrung in Beton N2 - Die Ermittlung der genauen Bewehrungslage ist von großem Interesse bei der Instandsetzung und Ertüchtigung von Stahlbetonbauwerken. Denn nur wenn die Lage der für die Standsicherheit wichtigen Bewehrung bekannt ist, können Kernbohrungen oder Sägearbeiten schadensfrei durchgeführt werden. Das Bodenradar als zerstörungsfreie Methode ist wegen des einfachen Verfahrens der Antenne entlang einer Messspur für eine solche Aufgabenstellung sehr gut geeignet. Die Anwendung kann aber eingeschränkt werden, wenn die gesuchte Bewehrung zu tief liegt oder durch eine davor liegende Bewehrung abgeschattet wird. Bei der Ortung mehrlagiger Bewehrung ist es wichtig, einen mehrstufigen und effizienten Messplan zu erstellen, der den Aufwand auf einem vertretbaren Maß beschränkt und die Möglichkeit bietet, beim Erreichen der Verfahrensgrenzen rechtzeitig die Untersuchung abzubrechen. Am Beispiel einer Stahlbetonbrücke, die nachträglich mit externen Spanngliedern versehen wurde, wird das Vorgehen beim Orten von mehrlagiger Bewehrung gezeigt. T2 - Georadar - Erfahrungen und Perspektiven CY - Freiberg, Germany DA - 24.09.2009 KW - Radar KW - Zerstörungsfreie Prüfung KW - Stahlbeton PY - 2010 SN - 0947-1944 VL - I SP - 1 EP - 6 PB - Dt. Geophysikalische Ges. CY - Potsdam AN - OPUS4-39827 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane A1 - Kind, Thomas A1 - Günther, Martin T1 - Ground penetrating radar in reflection vs transmission mode for void detection in concrete structures N2 - The concreting of prefabricated concrete structures can lead to insufficient bonding or even to remaining cavities. Honeycombs (aggregate clusters without cement) represent potential weakening of the structure and need to be detected non-destructively. In our study we tested the capability of ground penetrating radar (GPR) techniques for this purpose. We applied GPR in reflection mode and zero-offset profiling (ZOP) transmission mode on a precast concrete twin wall with built-in honeycombs. GPR measurements were performed as two channel measurement with ground coupled antennas with centre frequencies of 1.5 GHz and 2.6 GHz mounted to an automated scanner system. Our findings show that ZOP transmission measurements are a more efficient method to detect voids in reinforced concrete structures compared to reflection mode measurements. This holds for both the effort needed for the measurement and the evaluation as well as the validity of the data. Honeycombs (basically representing voids) are usually characterized by strongly reduced amplitudes and earlier arrivals of the transmitted wave. T2 - International Symposium Non-Destructive Tesing in Civil Engineering (NDT-CE 2015) CY - Berlin, Germany DA - 15.09.2015 KW - Void detection KW - Ground penetrating radar KW - Reflection KW - Transmission KW - Reinforced concrete KW - Prefabricated wall PY - 2015 AN - OPUS4-40005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Helmerich, Rosemarie A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Bien, J. A1 - Bernardini, G. ED - Hyun-Moo Koh, ED - Dan M. Frangopol, T1 - Complex multi-tool inspection of a masonry arch bridge using non-destructive testing T2 - Bridge Maintenance, Safety, Management, Health Monitoring and Informatics - IABMAS 2008 CY - Seoul, South Korea DA - 2008-07-13 PY - 2008 SN - 978-0-415-46844-2 SP - 1 EP - 8 PB - CRC Press CY - Boca Raton AN - OPUS4-17744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Helmerich, Rosemarie A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Bien, J. A1 - Kaminski, T. A1 - Bernardini, G. T1 - Multi-tool inspection and numerical analysis of an old masonry arch bridge N2 - Complex special inspection of an old masonry arch bridge according to the Guideline on Inspection and Condition Assessment of Railway Bridges and numerical analysis of the structure are presented. The guideline summarises recommendations for the step-by-step investigation of railway bridges applying enhanced methods developed during the EU-funded project Sustainable Bridges. For the investigation of the arch barrel, the ballast parameters and the inner structure of the backfill behind the arch barrel a number of various advanced non-destructive and minor-destructive testing methods were applied. Deformation of the structure during load tests was measured using three independent measuring systems: laser vibrometer, LVDT and microwave radar. Results of calculations performed with 2D and 3D models based on FEM are compared with the field load tests. Sensitivity of the ultimate load of the structure to investigated parameters is studied in FE model. Some general conclusions according to methods of testing and modelling of masonry arch bridges are presented and discussed. KW - Masonry bridges KW - Non-destructive testing KW - Bridge inspection KW - Finite element method PY - 2010 DO - https://doi.org/10.1080/15732471003645666 SN - 1573-2479 SN - 1744-8980 IS - NSIE_A_465075 SP - 1 EP - 13 PB - Taylor & Francis CY - London AN - OPUS4-22838 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Helmerich, Rosemarie A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Bien, J. A1 - Kaminski, T. A1 - Bernardini´, G. T1 - Multi-tool inspection and numerical of an old masonry arch bridge N2 - Complex special inspection of an old masonry arch bridge according to the Guideline on Inspection and Condition Assessment of Railway Bridges and numerical analysis of the structure are presented. The guideline summarises recommendations for the step-by-step investigation of railway bridges applying enhanced methods developed during the EU-funded project Sustainable Bridges. For the investigation of the arch barrel, the ballast parameters and the inner structure of the backfill behind the arch barrel a number of various advanced non-destructive and minor-destructive testing methods were applied. Deformation of the structure during load tests was measured using three independent measuring systems: laser vibrometer, LVDT and microwave radar. Results of calculations performed with 2D and 3D models based on FEM are compared with the field load tests. Sensitivity of the ultimate load of the structure to investigated parameters is studied in FE model. Some general conclusions according to methods of testing and modelling of masonry arch bridges are presented and discussed. KW - Masonry bridges KW - Non-destructive testing KW - Bridge inspection KW - Finite element method PY - 2012 SN - 1573-2479 VL - 8 IS - 1 SP - 27 EP - 39 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-27425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane A1 - Niederleithinger, Ernst T1 - Geophysikalische Untersuchungen zur Zustandsbewertung einer historischen Mauerwerksbrücke in Polen T2 - Jahrestagung Deutsche Geophysikalische Gesellschaft CY - Aachen, Germany DA - 2007-03-26 PY - 2007 AN - OPUS4-14683 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kruschwitz, Sabine A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Wöstmann, Jens T1 - Complex resistivity (CR) behavior of building material - first results of field scale measurements T2 - Near Surface 2008 - 14th European Meeting of Environmental and Engineering Geophysics (EAGE) CY - Kraków, Poland DA - 2008-09-15 KW - Building materials KW - Damage KW - Non-destructive testing KW - Complex resistivity PY - 2008 SN - 978-90-73781-56-6 SP - 1 EP - 4 AN - OPUS4-17908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cotic, P. A1 - Jaglicic, Z. A1 - Niederleithinger, Ernst A1 - Effner, Ute A1 - Kruschwitz, Sabine A1 - Trela, Christiane A1 - Bosiljkov, V. T1 - Effect of moisture on the reliability of void detection in brickwork masonry using radar, ultrasonic and complex resistivity tomography N2 - The influence of moisture on the reliability of detection of larger voids in brickwork masonry was investigated using three non-destructive techniques: radar, ultrasonic and complex resistivity (CR). Radar and ultrasonic travel time tomography, as well as CR tomography, were performed over a specific cross section of a specimen containing a large void at a known position to determine the influence of different levels of moisture content in the brickwork on the wave velocities and the CR magnitude. We defined a numerical estimator to quantitatively determine the void detection efficiency from the images obtained when exposing the specimen to moisture. The results showed radar to be the most reliable technique for void detection in both dry and wet masonry, while CR performed much better in detecting larger air voids in wet masonry. KW - Radar KW - Ultrasonic and complex resistivity KW - Tomography KW - Masonry KW - Moisture KW - Void detection KW - Ultrasound PY - 2013 DO - https://doi.org/10.1617/s11527-012-0011-3 SN - 1359-5997 SN - 1871-6873 VL - 46 IS - 10 SP - 1723 EP - 1735 PB - Springer CY - Dordrecht AN - OPUS4-29991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Kruschwitz, Sabine A1 - Martin, Tina A1 - Trela, Christiane T1 - Geophysical investigation of tailings dams - the TAILSAFE challenge N2 - One of the main problems in the assessment of the operability, stability and contamination potential of tailings facilities is the lack of data on subsurface materials, properties and structures. One key task in the use of geophysics is the selection of the proper methods for a given site/problem combination. Interpretation of the acquired and processed physical data (e.g. electrical resistivity distribution) into something useful for site assessment (e.g. contamination distribution) is another. In the TAILSAFE project (funded by the European Commission) we have worked with partners on the use of geophysics for tailings facilities inspection. DC and complex resistivity, ground penetrating radar, and spectral analysis of surface waves and multichannel analysis of surface waves have been used on dams and beaches. In most cases, our methods provided useful information on the subsurface structure, but the translation of geophysical values into geotechnical or other parameters is still challenging. KW - Geophysics KW - Geoelectrics KW - Ground penetrating radar KW - Spectral analysis of surface waves KW - Tailings PY - 2007 SN - 0967-0513 VL - 15 IS - 2 SP - 157 EP - 162 PB - EPP Publ. CY - Richmond AN - OPUS4-25080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -