TY - CONF A1 - Niederleithinger, Ernst T1 - Advances in ultrasonic testing and monitoring of concrete structures N2 - Recent years have seen extended use of ultrasonic techniques for concrete infrastructure assessement. They are applied for quality assurance and condition assessement at bridges, power plants, dams and other important objects. However, there are still a couple of significant limitations. They include, but are not limited to depth of penetration, imaging complex structures or early stage detections of distributed damage. The talk will give information on recent research in this area. Specifically, the application of the unique deep penetration system LAUS is shown. Ultrasonic monitoring using embedded transducers to check for subtle and sudden changes in the material is introduced as well. Comments on initiatives for validation, standardization and certification will be given. T2 - 341e Conférence CERES CY - Online meeting DA - 26.10.2020 KW - Concrete KW - Ultrasound KW - Imaging KW - Monitoring PY - 2020 AN - OPUS4-51463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Imani, A. A1 - Niederleithinger, Ernst T1 - Nondestructive Evaluation of Bridges without Structural Plans for Load Rating Purposes N2 - According to the NBI database, more than 21,000 in-service U.S. bridges lack sufficient structural documentation necessary for analytical load rating. Among these are a significant proportion of older prestressed concrete bridges. Given the lack of documentation on the reinforcing layout, such structures cannot be load rated analytically and are often subject to engineering judgement as the basis for rating. Otherwise, the typical approach for load rating such bridges is to conduct costly proof load testing and destructive probing together with making conservative assumptions. Therefore, any improvement to current practices will benefit DOTs and taxpayers alike. Accurately reconstructed 3D images of the girders to reflect the internal reinforcement could mitigate the need for costly, if not impractical, destructive testing and proof load testing, and help reduce dependency on conservative assumptions. This study examines a comprehensive NDE approach using ultrasonic tomography and GPR to aid in gathering structural information for load rating purposes. Different types of AASHTO and hollow core girders were tested. T2 - NDT-CE 2022 CY - Zurich, Switzerland DA - 16.08.2022 KW - Ultrasound KW - Radar KW - Bridges KW - Load rating PY - 2022 AN - OPUS4-56356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Coda wave interferometry used for monitoring of concrete constructions N2 - Ultrasonic transmission measurements on concrete; embedded transducers; coda wave interferometry to check for subtle chnages in velocity as indicator for various loads or deterioration. T2 - 76. Jahrestagung der Deutschen Geophysikalischen Gesellschaft CY - Münster, Germany DA - 14.03.2016 KW - Ultrasound KW - Transmission KW - Coda wave interferometry KW - Concrete KW - Load PY - 2016 AN - OPUS4-37721 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Niederleithinger, Ernst T1 - State-of-the-art of Ultrasonic Monitoring of Concrete N2 - Ultrasonic methods are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as deep penetration ultrasonic echo devices, new imaging techniques, embedded transducers for permanent monitoring and sensitive data processing techniques adopted from seismology have opened new fields of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks. KW - Ultrasound KW - Concrete KW - Monitoring KW - Imaging PY - 2016 IS - 10 SP - 15 EP - 18 AN - OPUS4-38728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - State-of-the-art ultrasonic monitoring of concrete N2 - Ultrasonic methods are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages. The presentation will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed. The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with or first installations in real constructions (bridges, tunnel) will also be presented. T2 - CBIR Research Seminar, University of Technology Sydney CY - Sydney, Australia DA - 05.12.2016 KW - Ultrasound KW - Concrete KW - Monitoring KW - Imaging PY - 2016 AN - OPUS4-38730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Progress in non-destructive testing and monitoring of concrete N2 - The presentation will give an overview on non-destructive testing techniques being developed at the Federal Institute for Materials Research and Testing, Germany (BAM). This includes ultrasonic methods, ground penetration radar, Laser-Induced Breakdown Spectroscopy (LIBS), infrared thermography, pile testing, sensor technology and building scanner. A focus of the talk will be ultrasonic methods, which are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages. The presentation will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed. The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with our first installations in real constructions (bridges, tunnel) will also be presented. T2 - CIE Research Seminar, University of Western Sydney, New South Wales CY - Sydney, Australia DA - 15.12.2016 KW - Ultrasound KW - Concrete KW - Monitoring KW - Imaging PY - 2016 AN - OPUS4-38732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Coelho Lima, Isabela A1 - Grohmann, Maria A1 - Niederleithinger, Ernst T1 - Alternative imaging conditions for reverse-time migration N2 - Poster on the evaluation of several imaging conditions for reverse time migration, applied to ultrasonic echo data, tested with synthetic (simulated) dat and real data from a polyamide model. T2 - Jahrestagung der Deutschen geophysikalischen Gesellschaft CY - Leoben, Austria DA - 12.2.2018 KW - Ultrasound KW - Reverse time migration KW - Imaging condition KW - Concrete KW - Polyamide PY - 2018 AN - OPUS4-44583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - Concepts from seismic interferometry transferred to sonic and ultrasonic concrete inspection and monitoring N2 - Seismic interferometry (SI) deals either with the sensible detection of changes in the subsurface or with the reconstruction of virtual signals between two receivers by crosscorrelation of signals from diffuse sources. These concepts can be applied in NDT in civil engineering for various purposes, e. g. to detect changes in bridges. Here it is demonstrated using data from a reference structure on our test site. Practical applications can be expected in the very near future. T2 - European Conference on Non-Destructive Testing (ECNDT) CY - Gothenburg, Sweden DA - 11.6.2018 KW - Ultrasound KW - Monitoring KW - Concrete KW - Interferometry KW - Coda PY - 2018 AN - OPUS4-46844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Coelho Lima, Isabela A1 - Niederleithinger, Ernst T1 - Alternative imaging conditions for reverse time migration N2 - Ultrasound echo is a widely used NDT technique for determining the internal geometry of structures. Reverse-time migration (RTM) has been recently introduced to NDT applications, as an imaging method for ultrasound data, to overcome some of the limitations (e.g. imaging steeply dipping reflector) experienced by the Synthetic Aperture Focusing Technique (SAFT), the most commonly used imaging algorithm for these measurements. The standard implementation of RTM also experiences some drawbacks caused by its imaging condition, which is based on the zero-lag of the cross-correlation between source and receiver wavefields and generates high-amplitude low-frequency artifacts. Three alternative imaging conditions, developed for seismic data applications, were tested for their ability to provide better images than the standard cross-correlation: illumination compensation, deconvolution and wavefield decomposition. A polyamide specimen was chosen for the simulation of a synthetic experiment and for real data acquisition. The migrations of both synthetic and real data were performed with the software Madagascar. The illumination imaging condition was able to reduce the low-frequency noise and had a good performance in terms of computing time. The deconvolution improved the resolution in the synthetic tests, but did not showed such benefit for the real experiments. Finally, as for the wavefield decomposition, although it presented some advantages in terms of attenuating the low-frequency noise and some unwanted reflections, it was not able to image the internal structure of the polyamide as well as the cross-correlation did. Suggestions on how to improve the cost-effectiveness of the implementation of the deconvolution and wavefield decomposition were presented, as well as possible investigations that could be carried out in the future, in order to obtain better results with those two imaging conditions. T2 - DGZfP Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Ultrasound KW - Reverse time migration KW - Imaging condition KW - Concrete PY - 2018 AN - OPUS4-44873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst T1 - The LAUS: First applications of a new system for ultrasonic imaging of very concrete structures N2 - The LAUS (Large Aperture Ultrasonic System) has been developed to image very thick concrete structures, which are not accessible for commercial systems. The device and the corresponding software is the result of joint research of BAM, an ultrasonic instrument manufacturer and University of Kassel, Germany. It consists of 12 separate arrays of 32 point-contact shear wave transducers each, which can be deployed in flexible configurations. Each array is combined with battery and transmitter, receiver and wireless communication electronics. Three case histories are presented. First the system was deployed on a 5-m thick heavily reinforced foundation slab. The reflection of the slab’s bottom was imaged clearly. In addition, a multiple reflection was registered, thus giving hope that even thicker elements might be imaged by the instrument. Second, the LAUS was used to investigate a massive bridge girder where a heavy rainstorm during concreting had led to imperfections that were visible after removing the formwork was removed. The LAUS could image tendon ducts in 1.8m depth and the backwall closely behind them. Some limited areas showed blurred reflections and were checked by drill holes; these areas were affected by diffuse damage which could be repaired by injections. Third, a large retaining wall was checked for thickness. Meanwhile, the LAUS has been used in underground waste deposits (nuclear and other) for quality assurance of sealing plugs. A confirmed penetration depth of about 7 m has been reached. T2 - ASNT SMT/NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.8.2018 KW - LAUS KW - Ultrasound KW - Imaging KW - Concrete PY - 2018 AN - OPUS4-45828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -