TY - CONF A1 - Trela, Christiane T1 - Radarmessungen mit Constant-Offset zur Untersuchung von Strukturschwächungen in Betonbauteilen T2 - 73. Jahrestagung der Deutschen Geophysikalischen Gesellschaft (DGG) CY - Leipzig, Germany DA - 2013-03-04 PY - 2013 UR - http://www.ufz.de/export/data/425/46632_DGG_2013_Tagungsprogramm_und_Abstracts.pdf AN - OPUS4-27802 LA - deu 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 - 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 - Kruschwitz, Sabine A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Wöstmann, Jens T1 - Complex resistivity and radar investigation of building material: First results of field scale measurements N2 - Moisture ingress is one of major damaging factors for masonry buildings. As the complex resistivity (CR) is sensitive to textural properties as well as to the pore fluid chemistry of wet porous media, its non-destructive application can provide helpful information for conservators. In a comprehensive laboratory study it has been shown that CR might even be able to distinguish between salt content and saturation degree in only one measurement. The combined use of electrical and electromagnetic measurement techniques in two field-scale flooding experiments has shown some unexpected differences. Possible reasons are discussed and it is shown that bringing together the information of both methods leads to a clearer picture. KW - Complex resistivity KW - Ground penetrating radar KW - Non-destructive testing KW - Masonry KW - Salt and moisture damage PY - 2010 DO - https://doi.org/10.2478/s11600-009-0019-4 SN - 1895-6572 SN - 1895-7455 VL - 58 IS - 1 SP - 96 EP - 113 PB - Springer CY - Warsaw AN - OPUS4-20575 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 - CONF A1 - Trela, Christiane 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 - 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 - 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 - Trela, Christiane ED - Meßinger, J. T1 - Untersuchungen zur Positioniergenauigkeit von automatisierten Radarmessungen N2 - Zunehmend müssen Bauwerke instandgesetzt oder für eine Umnutzung ertüchtigt werden. Für diese Objekte ist eine Zustandsbeschreibung notwendig. Für Neubauten steht wiederum die Qualitätssicherung beim oder kurz nach dem Bau im Vordergrund. Georadar als etabliertes zerstörungsfreies Prüfverfahren (ZfP) kann in beiden Fällen seinen Beitrag vor allem bei der Struktur- bzw. Schadenserkennung leisten. Neben der typischen Suche nach Bewehrungsstäben, metallischen Hüllrohren etc. ist das Auffinden von beliebig geformten Fehlstellen wie z. B. schlecht verdichtetem Beton oder gar Hohlräumen deutlich schwieriger. Grundsätzlich wachsen die Erwartungen an das Radarverfahren, möglichst immer kleinere Strukturen in besserer räumlicher Auflösung als bisher zu erkennen und zu lokalisieren. Gleichzeitig verschlechtern sich zunehmend die Randbedingungen für Radarmessungen, tiefer in das Bauteil hineinzusehen. Dieses Problem entsteht, wenn immer dichtere Bewehrung verbaut wird. Um dieser Problematik geometrisch und vom Signal-Rauch- Verhältnis gerecht zu werden, sind Messungen in einem sehr feinen Raster und möglichst in 3D erforderlich. Dies kann insbesondere unter Berücksichtigung der Kosten nicht mehr mit Handmessungen allein gelöst werden. Im Folgenden wird die automatisierte Messwerterfassung bei Radarmessungen für das Bauwesen vorgestellt und es wird gezeigt, welchen Einfluss die präzise Triggerung der Messwerterfassung auf die Genauigkeit des Messergebnisses hat. T2 - Georadar - Erfahrungen und Perspektiven CY - Freiberg, Deutschland DA - 06.10.2011 KW - Radarmessungen KW - Automatisierung KW - Messgenauigkeit PY - 2012 SN - 0947-1944 VL - I SP - 39 EP - 44 PB - Dt. Geophysikalische Ges. CY - Potsdam AN - OPUS4-25768 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane A1 - Kind, Thomas A1 - Schubert, Marcus T1 - Positioning accuracy of an automatic scanning system for GPR measurements on concrete structures N2 - Most GPR measurements use hand-held survey wheels for positioning, something not feasible in some scenarios, such as measuring a tall retaining wall, tunnels or if tedious and repetitive measurements are required. For situations like these an automated positioning system is required and was therefore developed at BAM. Such a system was tested to calibrate the positioning of a GPR grid measurement which was performed in regular one-direction traverse mode and in a meandric mode. The preliminary results show a systematic error in the positioning, which depends on the traveling speed of the scanning system, because there is an electronic delay of the trigger signal. These errors are duplicated in meandric mode compared to the errors occurring in one-direction traverse mode. This may be insignificant when larger objects are investigated, but can be important for the identification and location of small objects which show weaker reflections, like e.g. compacting faults with a size of a honeycomb. T2 - 14th International conference on ground penetrating radar - GPR 2012 CY - Shanghai, China DA - 04.06.2012 KW - Automated scanning systems KW - Accuracy of positioning KW - Ground penetration radar PY - 2012 SN - 978-1-4673-2663-6 VL - I SP - 309 EP - 313 AN - OPUS4-26074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Niederleithinger, Ernst A1 - Trela, Christiane A1 - Wöstmann, Jens T1 - Use of complex resistivity tomography for moisture monitoring in a flooded masonry specimen N2 - Moisture ingress is one of the major deteriorating factors for building materials. Today, the only approved way to assess such damage is the gravimetric Darr method, which is essentially destructive. Substantial progress has been made using the geophysical complex-resistivity method, which can be applied non-destructively and provides spatial information along two-dimensional sections, rather than punctual along one borehole. Considerable advantages of complex resistivity are its sensitivity to textural properties, as well as the pore-fluid chemistry of wet, porous media. In a comprehensive laboratory study, and later in field scale experiments, it could be shown that complex resistivity may even be able to distinguish between salt content and saturation degree in a single measurement. A comparison with complementary nondestructive testing techniques points to the benefit and further research to be explored in multimethodical approaches. KW - Moisture KW - Salt KW - Masonry KW - Damage KW - Electrical resistivity KW - Radar KW - Radiography KW - Microwaves KW - Ground-penetrating radar KW - Microwave transmission PY - 2012 DO - https://doi.org/10.1061/(ASCE)IS.1943-555X.0000053 SN - 1076-0342 SN - 1943-555X VL - 18 IS - 1 (Special issue) SP - 2 EP - 11 CY - New York, NY AN - OPUS4-29536 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 DO - https://doi.org/10.1080/15732471003645666 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 -