TY - CONF A1 - Trela, Christiane A1 - Kind, Thomas A1 - Schubert, Marcus T1 - Detection of air voids in concrete by radar in transmission mode N2 - Air voids in concrete like honeycombs are one of the major concerns regarding quality assurance for the construction of infrastructure buildings like bridges or tunnels. This paper shows that voids in reinforced concrete walls or slabs can be detected by two standard ground coupled GPR antennas in transmission mode using a two-side zero-offset profiling configuration like in borehole radar applications. For the detection of voids only the amplitudes of the direct wave in transmission mode are evaluated. Even when the depth of the void can not be detected in this configuration, the major advantage of the zero-offset profiling in transmission mode is a lower interference with the surrounding reinforcement compared to a regular one-side reflection profiling. The capability of the two-side zero-offset profiling is demonstrated on a test specimen with a set of polystyrene balls of two different sizes representing voids like honeycombs in concrete. GPR measurements are realized by an automated scanning system in order to allow for a synchronous movement of the antennas. In transmission mode voids can be detected at greater depths compared to reflection mode, since the travel path of the direct wave is half as long. Another characteristic of the transmission mode is that the direct wave through the air voids is faster and arrives earlier than the direct wave in the surrounding concrete. Hence it can be separated from the strong reflection of the reinforcement. Finally the measurements in transmission mode are less sensitive to the antenna frequency and polarization than in reflection mode. T2 - IWAGPR 2015 - 8th International workshop on advanced ground penetrating radar CY - Firenze, Italy DA - 07.07.2015 KW - Radar KW - Zerstörungsfreie Prüfung KW - Ground penetrating radar KW - Transmission KW - Reinforced concrete KW - Honeycombs KW - Void detection KW - First arrival PY - 2015 SN - 978-1-4799-6495-6 DO - https://doi.org/10.1109/IWAGPR.2015.7292650 AN - OPUS4-34678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Trela, Christiane A1 - Wöstmann, Jens A1 - Kruschwitz, Sabine ED - Carlos Brebbia, T1 - Contribution of radar measurements to the inspection and condition assessment of railway bridges - case study at a historic masonry arch bridge in Olesnica/Poland N2 - Ground Penetration Radar (GPR) as a non-destructive (NDT)-method can be applied to obtain detailed information about the inner structure and condition of bridges without damaging the structure. In this paper the capabilities and limitations of the application of the fast inspection technique GPR will be demonstrated. In addition to GPR investigations, geoelectrical measurements, coring and petrophysical investigations have been carried out. The investigated railway bridge in Olesnica is a typical European masonry arch bridge (age, construction and span length). It shows typical damage to the masonry arches such as increasing salt concentration, destruction, material losses and longitudinal cracks. Radar measurements were carried out with two main objectives: (1) Identification of basic geometric dimensions of the bridge and identification of construction details; (2) Evaluation of the condition of the masonry, such as mechanical damage (e.g. cracks) or variation of the moisture content. Radar antennas of different frequencies (having different penetration depths) have been used to estimate the thickness of the walls. Because of the high attenuation in the inner masonry structure the measurements have not produced satisfying results, but the radar measurements have been successfully applied to investigate the moisture distribution in the masonry. These results have been verified by coring and through geoelectrical measurements. Cracks were studied at two testing areas at one wing wall of the bridge using an automatic 2D radar scanning system. The radar data were processed using advanced data processing tools like FT-SAFT reconstruction and data fusion. The processing sequence allowed the creation of high-resolution depth sections (C-Scans). KW - Ground Penetration Radar KW - Spectral induced polarization KW - Coring KW - Railway bridge KW - Non-destructive testing method KW - Condition assessment PY - 2008 SN - 978-1-84564-106-1 DO - https://doi.org/10.2495/HPSM080541 SN - 1743-3509 VL - 97 SP - 535 EP - 544 PB - WIT Press CY - Ashurst, Southampton, UK AN - OPUS4-17745 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bien, J. A1 - Kaminski, T. A1 - Trela, Christiane ED - Hyun-Moo Koh, ED - Dan M. Frangopol, T1 - Numerical analysis of old masonry bridges supported by field tests 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 - 2384 EP - 2391 PB - CRC Press CY - Boca Raton AN - OPUS4-17749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paasche, H. A1 - Wendrich, Astrid A1 - Tronicke, J. A1 - Trela, Christiane T1 - Detecting voids in masonry by cooperatively inverting P-wave and georadar traveltimes N2 - Collecting different geophysical data sets at the same object and site offers the opportunity to reduce uncertainties and ambiguities in data analysis and interpretation. To be effective, the different available data sets should be linked during the model-generation process, e.g. by cooperative inversion. In this study, we apply a recently developed zonal cooperative inversion approach based on fuzzy c-means cluster analysis to a non-destructive testing experiment. After briefly reviewing the fundamentals of the inversion strategy, we present a synthetic study investigating the potential of the method to detect air-filled voids in masonry by using ultrasonic and georadar traveltime data. Then, we present and discuss laboratory experiments including the results of cooperatively inverted ultrasonic and georadar traveltimes collected at a masonry test specimen. The geometry of the specimen is known and is thus an ideal test object for a first-time real application of the novel zonal cooperative inversion procedure. Compared to the results of separate inversions of ultrasonic and georadar traveltimes, the zonal cooperative inversion allows for an improved delineation of the size and position of the cavities. The P-wave and georadar velocities determined for the model regions corresponding to the cavities are also improved. KW - Non-destructive testing KW - Tomography KW - Traveltime KW - Cooperative inversion KW - Cluster analysis PY - 2008 DO - https://doi.org/10.1088/1742-2132/5/3/002 SN - 1742-2132 VL - 5 SP - 256 EP - 267 PB - IOP Publ. CY - Bristol AN - OPUS4-18815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trela, Christiane A1 - Gil, Magdalena ED - Meßinger, J. T1 - Bodenuntersuchungen mit Georadar zum Auffinden von Grenzsteinen KW - Bodenuntersuchung KW - Georadar KW - Grenzsteine KW - Radar PY - 2010 SN - 0947-1944 VL - I SP - 7 EP - 14 PB - Dt. Geophysikalische Ges. CY - Potsdam AN - OPUS4-21836 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Ergebnisse aus dem Teilprojekt der BAM: Bodenuntersuchungen mit Georadar zum Auffinden von Grenzsteinen T2 - Radar-Rundtischgespräch an der TU Bergakademie Freiberg, Institut für Geophysik CY - Freiberg, Germany DA - 2009-09-24 PY - 2009 AN - OPUS4-20120 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cruz, P.J.S. A1 - Topczewski, L. A1 - Fernandes, F.M. A1 - Trela, Christiane A1 - Lourenco, P.B. T1 - Application of radar techniques to the verification of design plans and the detection of defects in concrete bridges N2 - Non-destructive tests (NDT) are an essential tool used in special inspections to gather detailed information about the condition of a bridge. The inspection of bridge decks is a critical task, and, currently, can be successfully carried out using a wide range of NDT techniques. Nevertheless, some of these techniques are excessively expensive and time consuming. One of these techniques, the ground penetrating radar (GPR), has been used for some decades in the non-destructive inspection and diagnosis of concrete bridges. GPR is useful to find general information about the true position of reinforcement and tendon ducts, and check the quality of the construction and materials. A significant number of reinforced and prestressed concrete bridges are deteriorating at a rapid rate and need to be repaired and strengthened. During these rehabilitation processes, designers are often faced with a lack of original design plans and unawareness of the real position of reinforcement and tendon ducts. In this paper, three case studies of the use of GPR techniques for the inspection of concrete bridges are presented and analysed. The main aim of this research is to show the strong need and usefulness of these techniques, which can provide non-visible information about structural geometry and integrity required for strengthening and rehabilitation purposes. KW - Non-destructive tests KW - Ground penetrating radar KW - Tomography KW - Bridge condition assessment KW - Detection of defects PY - 2010 DO - https://doi.org/10.1080/15732470701778506 SN - 1573-2479 SN - 1744-8980 VL - 6 IS - 4 SP - 395 EP - 407 PB - Taylor & Francis CY - London AN - OPUS4-20144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kind, Thomas A1 - Feistkorn, Sascha A1 - Trela, Christiane A1 - Wöstmann, Jens T1 - Impulsradar für schadensfreie Kernbohrungen an Spannbetonbrücken N2 - Der Bedarf an Kernbohrungen in Stahlbetonbauwerken ist in den letzten Jahren durch die steigende Anzahl von Instandsetzungen und Ertüchtigungen unterschiedlicher Stahlbetonbauten stark gewachsen. Für die Durchführung einer Kernbohrung ist die Kenntnis der genauen Lage der vorgespannten Bewehrung notwendig, um diese für die Statik wichtigen Elemente nicht zu beschädigen. Das methodische Vorgehen für die schadensfreie Durchführung von Kernbohrungen wird am Beispiel einer ca. 1 m dicken Hohlkastenseitenwand der Karl-Carstens Brücke in Bremen gezeigt. Nach der Darstellung der Ausgangslage und der Aufgabenstellung werden die Schritte beschrieben, die zu einer erfolgreichen Durchführung der Aufgaben erforderlich waren. Hierbei steht die planmäßige Anwendung der zerstörungsfreien Untersuchungsmethode Impulsradar im Vordergrund. Das Vorgehen gliedert sich in vier Schritte: - Zunächst wurde eine Voruntersuchung durchgeführt, um festzustellen, ob sich die vorgespannte Bewehrung in den erwarteten Tiefen von bis zu 50 cm und unter den vorhandenen Bedingungen der Hohlkastenseitenwände mit dem Impulsradar detektieren lässt. - Nach der erfolgreichen Voruntersuchung wurden im zweiten Schritt die Bereiche der geplanten Kernbohrungen großflächig mit dem Impulsradar untersucht. - Anschließend konnte anhand der Messdaten die Lage der Bewehrung ermittelt und in einen Plan eingezeichnet werden, der im Maßstab 1:1 ausgedruckt wurde. Dieser Plan wurde positionsrichtig auf die Oberfläche der Hohlkastenwand geklebt. - Im letzten Schritt wurden dann gezielte Test- und Suchbohrungen durchgeführt, denen die eigentlichen Kernbohrungen folgten. Mit der im Plan dargestellte Bewehrungslage war die Voraussetzung für schadensfreies Bohren gegeben. So konnten die Kernbohrungen durchgeführt werden, ohne die vorgespannte Bewehrung zu beschädigen. KW - Zerstörungsfreie Prüfung KW - Impulsradar KW - Stahlbetonbrücke KW - Ertüchtigung KW - Kernbohrung KW - Schubnadeln KW - Spannglieder PY - 2009 DO - https://doi.org/10.1002/best.200900060 SN - 0005-9900 SN - 1437-1006 VL - 104 IS - 12 SP - 876 EP - 881 PB - Ernst CY - Berlin AN - OPUS4-20657 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Application of ultrasonic and radar tomography for the investigation of the internal structure of masonry T2 - IIIrd Workshop of "NDT in Progress" CY - Prague, Czech Republic DA - 2005-10-10 PY - 2005 AN - OPUS4-11977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Radartomografie zur Strukturuntersuchung an Betonbauteilen T2 - 6. Radarrundtischgespräch an der TU Freiberg im Institut für Geophysik CY - Freiberg, Germany DA - 2005-09-29 PY - 2005 AN - OPUS4-11071 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane ED - Fertig, J. T1 - Radartomographie zur Strukturuntersuchung an Betonbauteilen N2 - Impulsradarmessungen in Reflexionsanordnung werden seit längerem mit Erfolg zur zerstörungsfreien Prüfung im Bauwesen eingesetzt. Ziel ist die strukturelle Untersuchungen wie z.B. der Verifizierung von Bauplänen durch Ortung von Bewehrungslagen und Spannkanälen und die Dickenbestimmungen [1]. Eine Vielzahl bisheriger Untersuchungen hat jedoch gezeigt, dass zur Lösung dieser Fragestellungen bei größeren Bauteildicken, dichterer Bewehrung und diffuseren Reflexionsobjekten häufig die reflektierte Signalenergie nicht ausreicht. Transmissionsverfahren und die Auswertung mit entsprechenden tomographischen Inversionsalgorithmen weisen hierbei ein Potential auf, das im folgenden Beitrag systematisch auf die Anwendung zur Strukturanalyse hin untersucht wird. Die begonnenen Untersuchungen dazu konzentrierten sich vor allem auf die Evaluierung des Radarverfahren für die Transmissionsmessungen an Betonbauteilen. Bei der systematischen Vorgehensweise wurde an Probekörpern gemessen und numerische Simulationen gerechnet. In einem ersten Schritt kamen laufzeittomographische Verfahren zum Einsatz. Neben räumlichen Strukturmerkmalen werden somit Materialeigenschaften wie die Verteilung des Betrages der Ausbreitungsgeschwindigkeiten der eingesetzten elektromagnetischen Wellen im Bauteil ermittelt. Die Arbeiten an der BAM dazu sind unter Mitwirkung einer Vielzahl von KollegInnen in verschiedenen Projekten eingebunden, so vor allem in dem EU-Vorhaben „Sustainable Bridges“ (www.sustainablebridges.net) und in der DFG-Forschergruppe FOR384 (www.for384.uni-stuttgart.de). T2 - Kolloquium Georadar CY - Freiberg, Deutschland DA - 2005-09-29 KW - Radar KW - Laufzeittomographie KW - Beton PY - 2006 SN - 0947-1944 N1 - Serientitel: Mitteilungen / Deutsche Geophysikalische Gesellschaft e.V. – Series title: Mitteilungen / Deutsche Geophysikalische Gesellschaft e.V. IS - 1 SP - 9 EP - 16 PB - DGG CY - Potsdam AN - OPUS4-14580 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kaminski, T. A1 - Trela, Christiane ED - Jan Bien, ED - Lennart Elfgren, ED - Jan Olofsson, T1 - Advanced methods of testing and analysis of old masonry bridge in Olesnica T2 - International Conference "Sustainable Bridges - Assessment for Future Traffic Demands and Longer Lives" CY - Wroclaw, Poland DA - 2007-10-10 PY - 2007 SN - 978-83-7125-161-0 SP - 461 EP - 472 PB - Dolnoslaskie Wydawnictwo Edukacyjne CY - Wroclaw, Poland AN - OPUS4-16121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Contribution of radar measurements to inspection and condition assessment of railway bridges - Case study at a historic masonry arch bridge in Olesnica/Poland T2 - STREMAH 2007, Tenth International Conference on Studies, Repairs and Maintenance of Heritage Architecture, Incorporating the Maritime Heritage Seminar CY - Prague, Czech Republic DA - 2007-07-04 PY - 2007 AN - OPUS4-16282 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Untersuchung zur Positioniergenauigkeit von automatisierten Radarmessungen T2 - Radar-Rundtischgespräch CY - Freiberg, Germany DA - 2011-09-06 PY - 2011 AN - OPUS4-24690 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Martin, Tina A1 - Trela, Christiane A1 - Kind, Thomas A1 - Gil, Magdalena A1 - Wöstmann, Jens T1 - Detection of granite landmarks in soil with GPR T2 - 13th International conference on ground penetrating radar CY - Lecce, Italy DA - 2010-06-21 KW - Ground penetrating radar (GPR) KW - Granite landmarks PY - 2010 SN - 978-1-4244-4605-6 IS - IEEE Catalog Number: CFP10538 SP - 478 EP - 482 AN - OPUS4-25323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trela, Christiane T1 - Positioning accuracy of an automatic scanning system for GPR measurement on concrete structures T2 - The 14th International Conference on Ground Penetrating Radar (GPR) CY - Shanghai, China DA - 2012-06-04 PY - 2012 AN - OPUS4-26023 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 -