TY - CONF A1 - Wiggenhauser, Herbert T1 - State-of-the-Art of Non-Destructive Testing Methods and Technologies for Nuclear Power Plant Safety-Related Concrete Structures T2 - First International Conference on Structural Integrity CY - Kalpakkam, India DA - 2014-02-04 PY - 2014 AN - OPUS4-30250 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shokouhi, Parisa A1 - Wolf, Julia A1 - Wiggenhauser, Herbert T1 - Detection of delamination in concrete bridge decks by joint amplitude and phase analysis of ultrasonic array measurements N2 - The accuracy and precision of low-frequency (center frequency of approximately 55 kHz) ultrasonic testing for detection and characterization of delamination in concrete bridge decks were evaluated. A multiprobe ultrasonic testing system (with horizontally polarized shear-wave transducers) was used to detect built-in delamination defects of various size, depth, and severity (i.e., thickness) in a test specimen—a 6.1 m × 2.4 m × 216 mm (20 ft × 8 ft × 8.5 in.) reinforced concrete slab-built to simulate a concrete bridge deck. The collected data sets were reconstructed applying synthetic aperture focusing technique (SAFT). The reconstructed measurement results were then used to assess the condition of the concrete slab at individual points [point-by-point data collection and two-dimensional (2D) reconstruction] as well as along lines, where data were collected at smaller steps and reconstructed in a three-dimensional (3D) format. The local-phase information was also calculated, superimposed on the reconstructed images and used as complementary information in condition assessment. The precision and accuracy of condition assessments were evaluated. The results indicated that, using the multiprobe ultrasonic array, delamination defects as small as 30 cm² (1 ft²) could be reliably detected. Deep delaminations [i.e., those deeper than 150 mm (6 in.)] were directly detected and characterized, whereas shallow delaminations [shallower than 65 mm (2.5 in.)] were detected only indirectly. The precision of the measurements was demonstrated by comparing repeated measurements at several test points. Similar measurement results obtained on a delaminated portion of a real bridge deck support the conclusions of the validation study. KW - Concrete bridge deck KW - Bridge deck evaluation KW - Delamination KW - Nondestructive testing (NDT) KW - Ultrasonic testing PY - 2014 DO - https://doi.org/10.1061/(ASCE)BE.1943-5592.0000513 SN - 1084-0702 VL - 19 IS - 3 SP - 04013005-1 EP - 04013005-11 PB - Soc. CY - Reston, Va. AN - OPUS4-31261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - FA ZfPBau - Welches sind die Zukunftsthemen? N2 - Vortrag über die bisherige Arbeit des Fachausschusses ZfP im Bauwesen und über mögliche zukünftige Themenfelder. T2 - FA ZfP im Bauwesen CY - Berlin, Germany DA - 11.05.2017 KW - DGZfP KW - Bauwesen KW - Zukunft PY - 2017 AN - OPUS4-40236 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Samokrutov, A A1 - Mayer, K A1 - Krause, Martin A1 - Alekhin, S. G. A1 - Elkin, V T1 - Large aperture ultrasonic system for testing thick concrete structures N2 - A Large Aperture UltraSonic system (LAUS) has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually on the surface to achieve optimal ultrasonic condition, e.g. to avoid rebars. For the generation of vacuum, air pressure is supplied to each unit through an air hose. The twelve units define an aperture which is necessary for fast reconstruction of the subsurface structure. The well-known SAFT (Synthetic Aperture Focusing Technique) algorithm has been adopted to this situation, where the individual LAUS units form a linear aperture with not necessarily equidistant spacing between the units. The exact geometrical position of the units, which are individually marked with retroreflective labels, is determined using photographs and image processing. All transducers are synchronized and work either as transmitter or receiver. A full scan consists of 12 * 11 recordings, where each unit acts as transmitter once and all others as receivers. An electronic sub-unit on the back of the ultrasonic device holds the battery and handles data acquisition, synchronization and data communication. A computer is used as base unit which communicates with each LAUS unit for control and data acquisition, the synchronization is performed by a radio modem that uses a special algorithm similar to a digital PLL (phase locked loop). No wire connections are necessary between the units and the base system. The LAUS system is designed to investigate concrete structures with thicknesses in excess of 2 m, depending on the acoustic condition of the object under investigation. Highly reinforced concrete may have less penetration depth. The LAUS provides quasi real time imaging, once the transducers are put in place and the data has been acquired. First measurements on a foundation slab confirm, that the system can register ultrasonic echoes from the back wall at 4 m distance. KW - Ultrasound "Large Aperture" NDT Concrete PY - 2017 DO - https://doi.org/10.1061/(ASCE)IS.1943-555X.0000314 SN - 1076-0342 SN - 1943-555X VL - 23 IS - 1 SP - B4016004-1 EP - B4016004-9 PB - American Society of Civil Engineers (ASCE) CY - Reston, VA 20191-4400 USA AN - OPUS4-39372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Sousa, J. A1 - Wiggenhauser, Herbert ED - Bittencourt, Frangopol & Beck, T1 - Application of a cross correlation technique for assessment of a non-homogeneous stress field N2 - Many researchers have addressed the determination of a homogeneous stress field from the analysis of ultrasound waves, using the theory of acoustoelasticity with Murnaghan´s constants derived for axially loaded specimens with the ultrasound wave path also in the axial direction, or for hydrostatically loaded specimens. However, the use of such strategy for structural healthy monitoring requires the ability to handle nonhomogeneous, arbitrarily oriented stress fields. This paper describes an attempt to evaluate changes in the stress field of a concrete block with an eccentrically placed tendon through acoustoelastic analysis. Pairs of acoustic transducers are placed on the surfaces such that wave paths are parallel to the tendon. A cross correlation technique is used for the accurate assessment of the sound velocity changes, and subsequent application of Murnaghan´s equations for assessing the stress changes. Results are promising with respect to the evaluation for non-homogeneous stress field from ultra sound velocities. KW - Cross correlation KW - Stress field PY - 2016 SN - 978-1-138-02851-7 SN - 978-1-4987-7703-2 SP - 237 EP - 237 PB - Taylor & Francis Group CY - London AN - OPUS4-39375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wai-Lok Lai, W. A1 - Kind, Thomas A1 - Fung-Chu Sham, J. A1 - Wiggenhauser, Herbert T1 - Correction of GPR wave velocity at different oblique angles between traverses and alignment of line objects in a common offset antenna setting N2 - Estimation of ground penetrating radar's wave velocity in materials is a critical step to accurately estimate depth of embedded line objects in concrete structures, and wetness of material. Errors of velocity are defined as the deviations between the velocities obtained in various oblique angles and those obtained in the traverse normal to the object orientation in a common offset antenna setting. In this paper, we quantified and corrected the errors of such estimation. GPR traverses were designed to travel in various oblique angles θ (90°, 75°, 60° and 45°) relative to the steel bars at 5 cover depths (55 mm, 85 mm, 115 mm, 145 mm and 175 mm). GPR wave velocity at any position within the lateral detection range of steel bars was measured with simple trigonometry in a semi-automated in-house program. It was found that reduction of oblique angles (i.e. θ<90°) causes flatter hyperbolic reflections and the associated errors of velocity can be as much as 30% in the case of an oblique angle 45° before correction. Such errors were corrected after re-scaling the horizontal travel distance with a multiplication factor of sin θ. KW - Ground penetrating radar KW - Oblique angles KW - Hyperbola KW - Velocity error PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S096386951630007X DO - https://doi.org/10.1016/j.ndteint.2016.03.003 VL - 82 SP - 36 EP - 43 PB - Elsevier Ltd. AN - OPUS4-37146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert A1 - Reinhardt, H.W. ED - Thompson, D.O. ED - Chimenti, D.E. T1 - NDT in civil engineering: experience and results of the FOR 384 research group T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Non-destructive testing in civil engineering KW - Ultrasonic pulse echo KW - Impact-echo KW - Ground penetrating radar KW - Validation KW - Concrete KW - Zerstörungsfreie Prüfung KW - Ultraschall Echo KW - Impact Echo KW - Radar KW - Beton KW - Validierung PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 29 SP - 47 EP - 54 CY - Melville, NY AN - OPUS4-34933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krause, Martin A1 - Mauke, R. A1 - Effner, Ute A1 - Milmann, Boris A1 - Völker, Christoph A1 - Wiggenhauser, Herbert T1 - Ultrasonic testing of a sealing construction made of salt concrete in an underground disposal facility for radioactive waste T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 2015-09-15 KW - Ultrasonic reflection measurement KW - Dry contact transducers in boreholes KW - Interface salt-concrete / rock salt KW - Ultrasonic imaging of internal reflectors PY - 2015 SN - 1435-4934 SP - 696 EP - 699 AN - OPUS4-34537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Samokrutov, A.A. A1 - Mayer, K. A1 - Krause, Martin A1 - Alekhin, S. G. A1 - Elkin, V. T1 - LAUS - Large aperture ultrasonic system - for testing thick concrete structures N2 - A Large Aperture UltraSonic (LAUS) system has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually depending on the surface condition and optimal ultrasonic condition, e.g. rebar position. Air pressure is supplied to each unit through an air hose. The following extended abstract is a short version of an article to be published in the special edition of ASCE JIS that will describe the outline of the system, the principle of functioning, the data processing and adapted reconstruction calculation based on SAFT as well as the system performance during first applications. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Ultrasonic imaging KW - Linear array KW - Reconstruction calculation (SAFT) PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345383 UR - http://www.ndt.net/?id=18313 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 4 PB - NDT.net CY - Kirchwald AN - OPUS4-34538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - LAUS - LARGE APERTURE ULTRASONIC SYSTEM for testing thick concrete structures T2 - Abteilungsseminar der Abteilung 8 "Zerstörungsfreie Prüfung" CY - BAM, Berlin, Deutschland DA - 2015-12-14 PY - 2015 AN - OPUS4-35089 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - LAUS - Large Aperture Ultrasonic System - for Testing Thick Concrete Structures T2 - International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE) CY - Berlin DA - 2015-09-15 PY - 2015 AN - OPUS4-34373 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Nondestructive testing in Civil Engineering T2 - Golden Jubilee celebration of SERC Recent Advances in Structural Engineering CY - Indien DA - 2015-05-07 PY - 2015 AN - OPUS4-34374 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Classification of Nondestructive Evaluation Tasks for Reinforced Concrete Structures T2 - Transportation Research Board 94th Annual Meeting CY - Washington, D. C. DA - 2015-01-11 PY - 2015 AN - OPUS4-34375 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Gucunski, N. A1 - Imani, A. A1 - Romero, F. A1 - Nazarian, S. A1 - Yuan, D. A1 - Wiggenhauser, Herbert A1 - Shokouhi, Parisa A1 - Taffe, Alexander A1 - Kutrubes, D. T1 - Nondestructive testing to identify concrete bridge deck deterioration N2 - This work was sponsored by the Federal Highway Administration in cooperation with the American Association of State Highway and Transportation Officials. It was conducted in the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies. The project was managed by Monica Starnes, Senior Program Officer for SHRP 2 Renewal. The research reported herein was performed by the Center for Advanced Infrastructure and Transportation (CAIT) at Rutgers University (RU); the Center for Transportation Infrastructure Systems (CTIS) at The University of Texas at El Paso (UTEP); the Federal Institute for Materials Research and Testing (BAM), Germany; and Radar Systems International, Inc. (RSI). Rutgers University was the coordinator and contractor for this project. Dr. Nenad Gucunski, professor and chair of Civil and Environmental Engineering and director of CAIT’s Infrastructure Condition Monitoring Program at RU, was the principal investigator. The other authors of this report are Dr. Soheil Nazarian, professor of Civil Engineering and director of CTIS at UTEP; Dr. Deren Yuan, research associate at CTIS at UTEP; Dr. Herbert Wiggenhauser, head of Non-Destructive Testing (NDT) in Civil Engineering at BAM; Dr. Alexander Taffe, leader of Combination and Automation of NDT of Buildings at BAM; Dr. Parisa Shokouhi, Alexander von Humboldt Research Fellow, hosted by BAM; and Doria Kutrubes, president of RSI. Arezoo Imani and Touraj Tayebi, graduate research assistants at RU, helped conduct the validation testing, data analysis, and web manual content preparation. Hoda Azari, a graduate research assistant, and Dr. Manuel Celaya, a research engineer at UTEP, assisted in the validation study as well. Hooman Parvardeh, research assistant at RU, helped build the reference database and develop the framework for the web manual, while Erica Erlanger, a research staff member at RU, edited the manuscript. Their contributions are gratefully acknowledged. The research team also gratefully acknowledges contributions of the participants from industry and academia in the validation testing. The participants include NDT Corporation; Germann Instruments; Olson Engineering; Dr. Ralf Arndt, National Research Council associate at FHWA Turner–Fairbank Highway Research Center; Ingegneria Dei Sistemi S.p.A. (IDS), Italy; 3D-RADAR, Norway; Dr. John Popovics, University of Illinois at Urbana-Champaign; Dr. Jinying Zhu, The University of Texas at Austin; Rutgers University—Center for Advanced Infrastructure and Transportation; and The University of Texas at El Paso—Center for Transportation Infrastructure Systems. The contributions of these participants were critical for the evaluation and grading of the performance of NDT technologies. PY - 2013 UR - http://onlinepubs.trb.org/onlinepubs/shrp2/SHRP2_S2-R06A-RR-1.pdf SN - 978-0-309-12933-6 SP - 1 EP - 96 PB - Transportation Research Board, Washington D.C. AN - OPUS4-34732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiggenhauser, Herbert A1 - Azari, H. T1 - Classification of nondestructive evaluation tasks for reinforced concrete structures N2 - Abstract: Nondestructive evaluation (NDE) methods have received growing acceptance in many testing tasks in the assessment of concrete infrastructures. Substantial progress in NDE methods for concrete structures can be achieved by discussing the specifics of each testing scenario. Because of the large variety of testing scenarios, the testing tasks must be isolated into subtasks, which can then be solved by NDE methods. A classification scheme for NDE tasks is described and discussed in this paper. Four major groups have been identified: the construction process, the concrete structure, physical or chemical processes, and material properties. For each of these groups, a number of subtasks are described. Typical parameter ranges and Resolution requirements are illustrated and major influencing factors listed. Reference specimens may be designed to be used for performance evaluation, validation, and certification of NDE methods. The classifications can also be used to draft a research road map that benefits both the owners of infrastructure and the instrument developers. KW - Nondestructive testing in civil engineering KW - Classification KW - Test tasks KW - Reinforced Concrete PY - 2017 DO - https://doi.org/10.1061/(ASCE)IS.1943-555X.0000378 SN - 1076-0342 SN - 1943-555X VL - 23 IS - 4 SP - 04017021-1 EP - 04017021-8 PB - ASCE AN - OPUS4-40609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Application of NDT to nuclear structures N2 - The presentation is #4 of the lecture series within the CE5390 NDT&E Course at the “University of Texas at El Paso”, USA (UTEP): 1. Application of NDT to Transportation Infrastructure 2. Application of NDT to Pavements 3. Application of NDT to Tunnels 4. Application of NDT to Nuclear Structures 5. Ultrasonic Methods 6. Electrical Resistivity (ER) 7. Galvanostatic Pulse Measurement (GPM) 8. Half-Cell Potential (HCP) 9. Ground Penetrating Radar (GPR) to Infrastructure 10. Ground Penetrating Radar (GPR) to Pavements 11. Impact Echo (IE)/Ultrasonic Surface Waves (USW) 12. Infrared Thermography (IR) 13. Magnetic Flux Leakage (MFL) 14. Ultrasonic Tomography (UST) 15. Falling Weight Deflectometer/Light Weight Deflectometer 16. Spectral Analysis of Surface Wave 17. Traffic Speed Deflectometer 18. Integrity of Foundations 19. Integration of Technologies Applications of NDT for nuclear structures are presented with an overview over the special challenges for NDE in this area. The lecture was held as a webinar on August 29, 2017 T2 - Webinar UTEP CE 5390 Special Topics Civil Engineering CY - Berlin, Germany DA - 31.08.2017 KW - Non-destructive testing in civil engineering KW - Nuclear structures PY - 2017 AN - OPUS4-41810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Non-destructive testing in civil engineering at BAM N2 - Non-Destructive assessment of the National Infrastructure in Germany has been the topic of R&D at BAM since many years. In 1989 BAM has established a R&D group dedicated to the development and application of Non-Destructive Testing in Civil Engineering. Since then, this group has left has participated in numerous research projects and cooperated with many researches and institutes worldwide. A complex system of inspection and maintenance is in place to inspect and maintain roads, bridges, tunnels and other installations. Based on visual inspection structures like bridges are inspected regularly. In case of concerns which cannot be resolved in this process, a procedure “Object Oriented Damage Analysis” has been put into place where additional inspection methods, especially NDT methods, are being utilized. NDT methods to establish material properties such as strength, porosity, moisture, carbonation, etc need more attention to strengthen the links between engineers and inspectors. BAM and TU Berlin have established a joint Junior Professor to address this research area with gravity. Research is currently focused on methods, data, validation, certification and standardization. Industry 4.0 has become a widely discussed topic with unforeseeable impact. Current research topics include - Large Aperture UltraSound (LAUS) to evaluate very thick concrete elements (> 1m) - Embedded ultrasound sensors to monitor changes in concrete - Data fusion algorithms for honeycomb detection, corrosion localization and reinforcement diameter determination - Reverse Time Migration to improve imaging of concrete structures - Laser Induced Breakdown Spectroscopy (LIBS) with new applications, improved sensitivity and resolution, new devices - RFID based humidity and corrosion sensors - Analysis of scattered Radar waves for the classification of concrete - Development of reference specimens for selected NDT tasks The presentation will present examples of current research and ideas for research directions. T2 - FHWA Seminar CY - Washington, D.C., USA DA - 25.07.2017 KW - Non-destructive Testing in Civil Engineering KW - Ultrasound; RFID KW - Ground Penetrating Radar KW - Laser Induced Breakdown Spectroscopy KW - Data Fusion KW - Large Aperture UltraSound (LAUS) KW - Monitoring of Concrete Structures KW - Reference Specimen PY - 2017 AN - OPUS4-41256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taffe, Alexander A1 - Kind, Thomas A1 - Stoppel, Markus A1 - Wiggenhauser, Herbert ED - M.G. Alexander, ED - H.-D. Beushausen, ED - F. Dehn, ED - P. Moyo, T1 - OSSCAR - Development of an On-Site SCAnneR for automated non-destructive bridge testing T2 - 2nd International Conference on Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 2008-11-24 KW - NDT KW - Automated bridge testing KW - Onsite scanner KW - Ultrasonic echo KW - Radar KW - Damage assessment KW - Damage analysis KW - OSSCAR PY - 2009 SN - 978-0-415-46850-3 SP - 541 EP - 545 PB - CRC Press CY - Boca Raton AN - OPUS4-18602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taffe, Alexander A1 - Wiggenhauser, Herbert A1 - Raupach, M. T1 - Validierung zerstörungsfreier Prüfverfahren im Bauwesen N2 - Die Validierung dient bereits in vielen Bereichen der Technik zum Nachweis, ob mit einem Verfahren Kundenanforderungen erfüllt werden können. Da gerade die im Bauwesen verwendeten zerstörungsfreien Prüfverfahren bis auf den Rückprallhammer nicht in einer deutschen Norm geregelt sind, kann die Validierung zur verbesserten Anwendungssicherheit nicht genormter Verfahren beitragen. Die Leistungsfähigkeit des Verfahrens wird für den Kunden transparent, so dass er die Güte der Messergebnisse einschätzen kann. Das ist besonders dann von Bedeutung, wenn aus dem Messergebnis eine belastbare Aussage abgeleitet werden soll und hohe Anforderungen bezüglich der Messgenauigkeit bestehen. So entsteht z. B. die Frage, welche Bauteildicke nach zerstörungsfreien Untersuchungen für eine statische Nachrechnung auf einem bestimmten Vertrauensniveau angesetzt werden kann oder mit welcher Sicherheit Pfahlgründungen, deren Länge ebenfalls zerstörungsfrei bestimmt wurde, in eine tragende Schicht einbinden. In dem Beitrag werden die Grundzüge der Durchführung einer Validierung beschrieben und am Beispiel der Dickenmessung an Fundamenten erläutert. Die beschriebene Vorgehensweise kann prinzipiell auf eine Vielzahl im Bauwesen auftretender Prüfaufgaben angewandt werden. Sind die Anforderungen an die Prüfaufgabe bezüglich der Genauigkeit nicht so hoch, können vereinfachte Abschätzungen der Messunsicherheit vorgenommen werden. KW - Zerstörungsfreie Prüfung im Bauwesen KW - Validierung KW - Messunsicherheit KW - Zuverlässigkeit KW - Ultraschallecho PY - 2008 DO - https://doi.org/10.1002/best.200800649 SN - 0005-9900 SN - 1437-1006 VL - 103 IS - 12 SP - 828 EP - 836 PB - Ernst CY - Berlin AN - OPUS4-18603 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taffe, Alexander A1 - Wiggenhauser, Herbert T1 - Zerstörungsfreie Zustandsermittlung und Qualitätssicherung in der Betoninstandsetzung KW - Zerstörungsfreie Prüfung im Bauwesen KW - Ultraschallecho KW - Impakt-Echo KW - Radar KW - Potentialfeldmessung KW - Radiografie KW - Übersicht PY - 2008 DO - https://doi.org/10.1002/best.200810201 SN - 0005-9900 SN - 1437-1006 VL - 103 IS - Dezember Spezial "Betonerhaltung" SP - 1 EP - 13 PB - Ernst CY - Berlin AN - OPUS4-18604 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Helmerich, Rosemarie A1 - Wiggenhauser, Herbert T1 - Non-destructive testing of concrete structures T2 - 4th International Conference on Advances in Mechanical Engineering and Mechanics (ICAMEM2008) CY - Sousse, Tunisia DA - 2008-12-16 KW - Non-destructive testing KW - Civil engineering KW - Inspection KW - Knowledge transfer KW - Case study PY - 2008 SP - 1 EP - 10 AN - OPUS4-18655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raupach, M. A1 - Reichling, K. A1 - Wiggenhauser, Herbert A1 - Stoppel, Markus A1 - Dobmann, G. A1 - Kurz, J. ED - M.G. Alexander, ED - H.-D. Beushausen, ED - F. Dehn, ED - P. Moyo, T1 - BETOSCAN - An instrumented mobile robot system for the diagnosis of reinforced concrete floors T2 - 2nd International Conference on Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 2008-11-24 KW - Corrosion KW - Diagnosis KW - Steel KW - Concrete KW - Reinforcement KW - NDT KW - Automated testing KW - Onsite scanner KW - Ultrasonic echo KW - Radar KW - Damage assessment KW - Damage analysis KW - Betoscan PY - 2009 SN - 978-0-415-46850-3 SP - 651 EP - 655 PB - CRC Press CY - Boca Raton AN - OPUS4-18668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Entwicklung und Anwendung zerstörungsfreier Prüfverfahren im Betonbau T2 - Kolloquium Konstruktiver Ingenieurbau (SS 2008) an der Universität Karlsruhe (TH) CY - Karlsruhe, Germany DA - 2008-06-26 PY - 2008 AN - OPUS4-17732 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert A1 - Taffe, Alexander A1 - Streicher, D. T1 - Brückenuntersuchung mit automatisierten Verfahren - Neue Entwicklungen T2 - Fachtagung Bauwerksdiagnose - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben CY - Berlin, Deutschland DA - 2008-02-21 KW - ZfPBau KW - Brückenprüfung KW - DIN 1076 KW - Automatisierung KW - Brückenscanner KW - Bildgebende Darstellung KW - Ultraschallecho KW - Radar KW - SAFT PY - 2008 SN - 978-3-940283-08-5 N1 - Serientitel: Berichtsband der Deutschen Gesellschaft für Zerstörungsfreie Prüfung – Series title: Berichtsband der Deutschen Gesellschaft für Zerstörungsfreie Prüfung IS - 112 SP - 1 EP - 8 (Vortrag 14) PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-17998 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Research in NDT-CE at BAM Berlin T2 - NDT Conference JSNT CY - Tokyo, Japan DA - 2006-08-01 PY - 2006 AN - OPUS4-18013 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Research in NDT-CE at BAM Berlin T2 - Seminar University of Texas at El Paso CY - El Paso, TX, USA DA - 2006-08-09 PY - 2006 AN - OPUS4-18014 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Research in NDT-CE at BAM Berlin T2 - Seminar Wayne State University CY - Detroit, MI, USA DA - 2006-08-21 PY - 2006 AN - OPUS4-18015 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Signal Analysis and Data Fusion of Multi Sensor NDE of Concrete T2 - National Seminar on Non-Destructive Evaluation NDE 2010 CY - Kolkata, India DA - 2010-12-09 PY - 2010 AN - OPUS4-22844 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Advanced NDT Methods for Quality Assurance of Concrete Structures T2 - National Seminar on Non-Destructive Evaluation NDE 2010 CY - Kolkata, India DA - 2010-12-09 PY - 2010 AN - OPUS4-22959 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beutel, R. A1 - Reinhardt, H.-W. A1 - Grosse, C.U. A1 - Glaubitt, A. A1 - Krause, Martin A1 - Maierhofer, Christiane A1 - Algernon, Daniel A1 - Wiggenhauser, Herbert A1 - Schickert, M. T1 - Comparative performance tests and validation of NDT methods for concrete testing N2 - Validation of non-destructive testing methods is necessary to create a common basis where different systems can be compared and their applications and limitations be identified. This can be achieved through comparing the measurements taken by several systems used for a common diagnostic purpose under practical but controlled testing conditions. Well-designed small and large laboratory or field specimens promise such conditions. The special concrete specimen (LCS) at BAM was constructed for validation purposes, in particular, to be used for evaluating the performance of echo methods. The thickness of the specimen is varying and it contains carefully designed built-in faults, such as voids, honeycombs and tendon ducts with various degrees of grouting defects. Since the geometry and condition of the defects are known, it can be used to compare the performance of radar, ultrasonic, impact-echo. The research was conducted within the Research group FOR384, sponsored by the German Research Society DFG. KW - Performance demonstration KW - Non-destructive testing KW - Concrete KW - Radar KW - Ultrasound KW - Impact-echo PY - 2008 DO - https://doi.org/10.1007/s10921-008-0037-1 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 59 EP - 65 PB - Plenum Press CY - New York, NY AN - OPUS4-17925 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Non-Destructive Assessment of Reinforced Concrete Structures with Combined Methods T2 - OECD - Nuclear Energy Agency Workshop: Ageing Management of Thick Walled Concrete Structures CY - Prague, Czech Republic DA - 2008-10-01 PY - 2008 AN - OPUS4-18118 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert T1 - Propagation time of elastic surface waves on concrete specimens under uniaxial loads T2 - NDE/NDT for Highways and Bridges - Structural Materials Technology (SMT) CY - Oakland, CA, USA DA - 2008-09-08 KW - Concrete KW - Surface wave KW - Load KW - Propagation time PY - 2008 SN - 978-1-57117-180-1 SP - 161 EP - 167 CY - Oakland, CA, USA AN - OPUS4-19114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert A1 - Fischer, G. T1 - Macro-effect of microcracks on sonic surface wave velocity in concrete under compression T2 - 89th TRB Annual Meeting CY - Washington, D.C., USA DA - 2010-01-10 KW - NDT KW - Microcracking KW - Sonic wave velocity KW - Concrete KW - Load KW - Stress PY - 2010 SP - 1 EP - 17 AN - OPUS4-20942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Neue Entwicklungen der zerstörungsfreien Prüfung im Bauwesen T2 - Fachtagung Bauwerksdiagnose CY - Berlin, Germany DA - 2010-02-18 PY - 2010 AN - OPUS4-20952 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Non-Destructive Testing in Civil Engineering T2 - Minnesota Department of Transportation CY - Minneapolis, MN, USA DA - 2010-01-22 PY - 2010 AN - OPUS4-20903 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Research in Non-Destructive Testing in Civil Engineering at BAM T2 - University of Minnesota, Warren Lecture Series - Spring 2010 CY - Minneapolis, MN, USA DA - 2010-01-22 PY - 2010 AN - OPUS4-20904 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Development of the On-Site SCAnneR (OSSCAR) T2 - Transportation Research Board (TRB) 89th Annual Meeting CY - Washington, D.C., USA DA - 2010-01-09 PY - 2010 AN - OPUS4-20900 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Application and Case Studies T2 - Transportation Research Board (TRB) 89th Annual Meeting, Workshop "Ultrasonic Imaging of Concrete" CY - Washington, D.C., USA DA - 2010-01-10 PY - 2010 AN - OPUS4-20901 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Non-Destructive Testing of Reinforced Concrete Structures at BAM T2 - National Research Council (NRC) CY - Washington, D.C., USA DA - 2010-01-20 PY - 2010 AN - OPUS4-20902 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taffe, Alexander A1 - Stoppel, Markus A1 - Wiggenhauser, Herbert T1 - Zerstörungsfreie Prüfverfahren im Bauwesen (ZfPBau) T2 - Betoninstandsetzung im Ingenieur- und Wohnungsbau CY - Filderstadt/Stuttgart, Deutschland DA - 2010-03-04 KW - Zerstörungsfreie Prüfung im Bauwesen KW - ZfPBau KW - Radar KW - Ultraschallecho KW - Automatisierung KW - Radiographie KW - OSSCAR KW - BetoScan PY - 2010 SP - 35 EP - 58 AN - OPUS4-20984 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Zerstörungsfreie Prüfverfahren bzw. Zerstörungsfreie Prüfung im Bauwesen (ZfPBau) in der BAM T2 - VSVI-Seminar Woche 2010 CY - Rendsburg, Germany DA - 2010-01-28 PY - 2010 AN - OPUS4-20953 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Zerstörungsfreie Prüfverfahren im Bauwesen - ein Überblick T2 - Informationstag "Moderne Bauwerksprüfung - Technische und rechtliche Aspekte" an der Bundesanstalt für Straßenwesen (BASt) CY - Bergisch Gladbach, Germany DA - 2010-11-10 PY - 2010 AN - OPUS4-22439 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Non-Destructive Testing in Civil Engineering T2 - Eingeladener Gastvortrag an der Ege Universität Izmir CY - Izmir, Turkey DA - 2010-10-17 PY - 2010 AN - OPUS4-22479 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reichling, K. A1 - Raupach, M. A1 - Wiggenhauser, Herbert A1 - Stoppel, Markus A1 - Dobmann, G. A1 - Kurz, J. T1 - BETOSCAN - A robotic system for simultaneous diagnoses of reinforced concrete structures T2 - NUCPERF 2009 - Long term performance of cementitious barriers and reinforced concrete in nuclear power plants and waste management CY - Cadarache, France DA - 2009-03-30 KW - Diagnosis KW - Steel KW - Reinforced concrete KW - BetoScan KW - Betonflächendiagnose KW - Scanner KW - ZfP im Bauwesen KW - Non destructive testing KW - Corrosion PY - 2009 SN - 978-2-35158-072-1 N1 - Serientitel: RILEM proceedings – Series title: RILEM proceedings IS - 64 SP - 1 EP - 7(?) PB - RILEM Publ. CY - Bagneux AN - OPUS4-22485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Reichling, K. A1 - Raupach, M. A1 - Wiggenhauser, Herbert A1 - Stoppel, Markus A1 - Dobmann, G. A1 - Kurz, J. ED - Odile Abraham, ED - Dérobert, Xavier T1 - BETOSCAN - Robot controlled non-destructive diagnosis of reinforced concrete decks T2 - NDTCE `09 - 7th international symposium on non destructive testing in civil engineering CY - Nantes, France DA - 2009-06-30 KW - BetoScan KW - Betonflächendiagnose KW - Scanner KW - ZfP im Bauwesen KW - Automation KW - Corrosion KW - Potential mapping KW - Repair KW - Non destructive testing KW - Diagnosis PY - 2009 SN - 978-2-7208-2542-5 SN - 1628-4704 IS - Paper 77 SP - 425 EP - 432 AN - OPUS4-22487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shokouhi, Parisa A1 - Zoëga, Andreas A1 - Wiggenhauser, Herbert ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Nondestructive evaluation of damage in concrete under uniaxial compression N2 - Surface wave velocities over the sonic frequency range (<20 KHz) were measured on concrete specimens undergoing various cycles of loading and unloading. Acoustic Emission test (AE) was conducted simultaneously to monitor the microcracking activities. The sonic surface wave velocity was found to be highly stress-dependent. The observed changes in surface wavespeed are repeatable and follow a particular trend. By measuring the wave velocities in both loading and unloading phases, the effects of stress and stress-induced damages could be distinguished. The observed trend could be explained by a combination of acoustoelasticity and microcracking theories. T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Nondestructive testing (NDT) KW - Microcracking KW - Sonic wave velocity KW - Concrete KW - Load KW - Stress PY - 2010 UR - http://link.aip.org/link/?APCPCS/1211/1525/1 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings SP - 1525 EP - 1532 CY - Melville, NY AN - OPUS4-22642 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Müller, H. S. A1 - Fenchel, M. A1 - Wiggenhauser, Herbert A1 - Maierhofer, Christiane A1 - Krause, Martin A1 - Gardei, André A1 - Mielentz, Frank A1 - Milmann, Boris A1 - Röllig, Mathias A1 - Wöstmann, Jens T1 - Zerstörungsfreie Ortung von Gefügestörungen in Betonbodenplatten N2 - Das Ziel des Forschungsvorhabens „Zerstörungsfreie Ortung von Gefügestörungen in Betonbodenplatten“ bestand in der Entwicklung eines Untersuchungskonzepts zur sicheren Ortung und Erfassung von Gefügestörungen in einseitig zugänglichen Betonplatten durch den kombinierten Einsatz verschiedener zerstörungsfreier Prüfverfahren. Hierfür wurde die Leistungsfähigkeit der folgenden Messverfahren hinsichtlich ihrer Aussageschärfe, Anwendungsgrenzen und Messgeschwindigkeit bei praxisnahen Randbedingungen untersucht: - Impakt-Echo, manuelle Impaktauslösung - Impakt-Echo, automatisierte Impaktauslösung - Ultraschall-Echo mit multistatischem Array - Impuls-Thermografie - Radar Als Versuchskörper dienten sechs liegend hergestellte Betonplatten der Abmessungen 200/200/30 cm aus zwei verschiedenen Betongüten und mit unterschiedlichem Bewehrungsgehalt (Bewehrungsgrade 0 %, 0 ,9 %, 2 ,6 %), von denen vier Platten auf trockenem und zwei Platten auf ständig nass gehaltenem Sand gelagert waren. Alle sechs Platten enthielten jeweils dieselben künstlich eingebrachten Fehlstellen: vier quadratische Kiesnester in unterschiedlicher Tiefe mit Kantenlängen zwischen 10 und 15 cm sowie drei oberflächennahe Hohlstellen (Ø 4/6/8 cm). Zur Erfassung eines möglichen Einflusses des Betonalters wurden die Messungen 4 Tage, 28 Tage sowie 180 Tage nach Herstellung der Platten durchgeführt. Um aus den Untersuchungen einen breiten Nutzen für die Praxis zu erzielen, basierten die eingesetzten Messverfahren auf handelsüblichen Geräten, welche jedoch bezüglich ihres Messprinzips und insbesondere der Datenerfassung und -auswertung weiterentwickelt wurden. Die Fehlstellengröße wurde bewusst klein gewählt. Mit Ausnahme des manuellen Impakt-Echo-Verfahrens, mit welchem unter Verwendung der Originalsoftware des Herstellers keine Fehlstellen nachweisbar waren, zeigten sich alle Messverfahren geeignet, unter verschiedenen Randbedingungen Gefügestörungen zu lokalisieren. Insgesamt wurde jeder Fehlstellentyp von zumindest einem Verfahren bei mindestens zwei Versuchskörpern detektiert. Es konnten jedoch an keiner Betonplatte mit einem einzelnen Messverfahren alle vorhandenen Fehlstellen an allen Messterminen geortet werden. Am häufigsten wurden die beiden großen oberflächennahen Fehlstellen (Hohlstelle Ø 8 cm, Kiesnest 10 cm) erkannt. Am schwersten zu lokalisieren waren die kleine Hohlstelle mit 4 cm Durchmesser sowie die beiden auf der Unterseite gelegenen Kiesnester. Die Untersuchungen zeigen, dass für eine erfolgreiche Anwendung zerstörungsfreier Messverfahren in der Praxis die Auswahl des am besten geeigneten Verfahrens bzw. einer Kombination verschiedener Verfahren jeweils auf die vorliegende Problemstellung abgestimmt sein muss. Für Betonbodenplatten mit hohem Feuchtegehalt (junger Beton) oder starker Bewehrung ist entweder das Ultraschall- oder das Impakt-Echo-Verfahren geeignet. Das Ultraschall-Verfahren wird von hohen Bewehrungsgehalten zwar stärker beeinflusst als das Impakt-Echo-Verfahren, besitzt aber eine bessere Auflösung und ermöglicht auch im oberflächennahen Bereich eine quantitative Bestimmung der Fehlstellentiefe. Das Impakt-Echo-Verfahren kann wegen der niederfrequenten Impulsanregung Fehlstellen erst in größeren Tiefen und mit schlechterer Auflösung nachweisen, ist aber ideal geeignet zur Bestimmung der Plattendicke aufgrund seines signifikanten Rückwandechos. Sowohl das Radar-Verfahren als auch die Impuls-Thermografie können bei hohen Feuchte- und Bewehrungsgehalten nur sehr oberflächennah eingesetzt werden. Bei trockenem Beton und geringen bis mittleren Bewehrungsgehalten liefert das Radar-Verfahren sehr gute Ergebnisse. In kurzer Zeit ermöglicht es eine flächendeckende Ortung der Tiefenlage und Größe von Inhomogenitäten bei guter Auflösungsgenauigkeit. Vorhandene Bewehrung wird deutlich abgebildet, kann aber darunterliegende Fehlstellen verschatten. Alternativ kann die Impuls-Thermografie für die Ortung oberflächennaher Gefügestörungen eingesetzt werden. Das Verfahren eignet sich insbesondere bei Oberflächen, die nicht direkt zugänglich sind, da zwischen Infrarotkamera und Messobjekt nur Sichtkontakt bestehen muss. Die Betongüte hatte bei keinem eingesetzten Verfahren einen erkennbaren Einfluss auf die Messergebnisse. Streng genommen ist dies jedoch nur für den Einfluss des Wasserzementwertes, der Zementart und des Zementgehalts bei gleichbleibender Sieblinie und gleicher Kornart gültig. Bei Verwendung von Leichtzuschlag sind abweichende Ergebnisse denkbar. PY - 2010 SN - 978-3-410-65075-1 SN - 0171-7197 IS - 589 SP - 1 EP - 88 PB - Beuth CY - Berlin AN - OPUS4-22699 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - OSSCAR - Development of an On-Site SCanneR for automated non-destructive bridge testing T2 - 2nd International Conference on Concrete Repair, Rehabilitation and Retrofitting ICCRRR 2008 CY - Cape Town, South Africa DA - 2008-11-24 PY - 2008 AN - OPUS4-18415 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiggenhauser, Herbert T1 - Development of a portable LIBS-device for quality assurance in concrete repair T2 - 2nd International Conference on Concrete Repair, Rehabilitation and Retrofitting ICCRRR 2008 CY - Cape Town, South Africa DA - 2008-11-24 PY - 2008 AN - OPUS4-18416 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zoëga, Andreas A1 - Shokouhi, Parisa A1 - Wiggenhauser, Herbert ED - Nagesh R. Iyer, ED - K. Balaji Rao, ED - N. Gopalakrishnan, ED - Bharatkumar, B. H. ED - V. Kalyanaraman, T1 - Propagation time of elastic surface waves on concrete specimens under uniaxial loads KW - Propagation time KW - Surface-wave KW - Concrete KW - Uniaxial loading KW - Laser vibrometer KW - Stress-dependency KW - Direction-dependency PY - 2009 SN - 0970-0137 VL - 36 IS - 1 SP - 11 EP - 15 CY - Madras AN - OPUS4-19462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -