scholarly journals Damage Detection at a Reinforced Concrete Specimen with Coda Wave Interferometry

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5013
Author(s):  
Stefan Grabke ◽  
Felix Clauß ◽  
Kai-Uwe Bletzinger ◽  
Mark Alexander Ahrens ◽  
Peter Mark ◽  
...  

Reinforced concrete is a widely used construction material in the building industry. With the increasing age of structures and higher loads there is an immense demand for structural health monitoring of built infrastructure. Coda wave interferometry is a possible candidate for damage detection in concrete whose applicability is demonstrated in this study. The technology is based on a correlation evaluation of two ultrasonic signals. In this study, two ways of processing the correlation data for damage detection are compared. The coda wave measurement data are obtained from a four-point bending test at a reinforced concrete specimen that is also instrumented with fibre optic strain measurements. The used ultrasonic signals have a central frequency of 60 kHz which is a significant difference to previous studies. The experiment shows that the coda wave interferometry has a high sensitivity for developing cracks and by solving an inverse problem even multiple cracks can be distinguished. A further specialty of this study is the use of finite elements for solving a diffusion problem which is needed to state the previously mentioned inverse problem for damage localization.

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4023
Author(s):  
Felix Clauß ◽  
Niklas Epple ◽  
Mark Alexander Ahrens ◽  
Ernst Niederleithinger ◽  
Peter Mark

Due to the high sensitivity of coda waves to the smallest structural alterations such as strain, humidity or temperature changes, ultrasonic waves are a valid means to examine entire structures employing networks of ultrasonic transducers. In order to substantiate this ex ante assessment, the viability of measuring ultrasonic waves as a valid point of reference and inference for structural changes is to be further scrutinized in this work. In order to investigate the influence of mechanical strain on ultrasonic signals, a four-point bending test was carried out on a reinforced concrete beam at Ruhr University Bochum. Thus, measurements collected from a network of selected transducer pairings arranged across the central, shear-free segment of the test specimen, were correlated to their respective strain fields. Detected ultrasonic signals were evaluated employing Coda Wave Interferometry. Such analysis comprised the initial non-cracked state as well as later stages with incremental crack depth and quantity. It was to ascertain that the test specimen can in fact be qualitatively compartmentalized into areas of compression and tension identified via Relative Velocity Changes presented in Attribute Maps. However, since results did not entail a zero crossing, i.e., neither positive nor negative values were to be calculated, only relative changes in this work displayed staggered over the height of the object under test, are discussed. Under the given methodological premises, additional information is currently required to make quantitative assertions regarding this correlation of ultrasonic and strain results. This holds true for the comparability of the ultrasonic and strain results for both non-cracked and even the cracked state.


Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1986 ◽  
Author(s):  
Xin Wang ◽  
Joyraj Chakraborty ◽  
Antoine Bassil ◽  
Ernst Niederleithinger

The enlargement of the cracks outside the permitted dimension is one of the main causes for the reduction of service life of Reinforced Concrete (RC) structures. Cracks can develop due to many causes such as dynamic or static load. When tensile stress exceeds the tensile strength of RC, cracks appear. Traditional techniques have limitations in early stage damage detection and localisation, especially on large-scale structures. The ultrasonic Coda Wave Interferometry (CWI) method using diffuse waves is one of the most promising methods to detect subtle changes in heterogeneous materials, such as concrete. In this paper, the assessment of the CWI method applied for multiple cracks opening detection on two specimens based on four-point bending test is presented. Both beams were monitored using a limited number of embedded Ultrasonic (US) transducers as well as other transducers and techniques (e.g., Digital Image Correlation (DIC), LVDT sensors, strain gauges, and Fiber Optics Sensor (FOS)). Results show that strain change and crack formation are successfully and efficiently detected by CWI method even earlier than by the other techniques. The CWI technique using embedded US transducers is undoubtedly a feasible, efficient, and promising method for long-term monitoring on real infrastructure.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4033
Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.


Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3879 ◽  
Author(s):  
Joyraj Chakraborty ◽  
Andrzej Katunin ◽  
Piotr Klikowicz ◽  
Marek Salamak

The damage in reinforced concrete (RC) structures can be induced either by the dynamic or static load. The inspection technologies available today have difficulty in detecting slowly progressive, locally limited damage, especially in hard-to-reach areas in the superstructure. The four-point bending test on the benchmark RC structure was used as a test of the quality and sensitivity of the embedded sensors. It allowed assessment of whether any cracking and propagation that occurs with the embedded sensors can be detected. Various methods are used for the analysis of the ultrasonic signals. By determining the feature from the ultrasonic signals, the changes in the whole structure are evaluated. The structural degradation of the RC benchmark structure was tested using various non-destructive testing methods to obtain a comprehensive decision about structural condition. It is shown that the ultrasonic sensors can detect a crack with a probability of detection of 100%, also before it is visible by the naked eye and other techniques, even if the damage is not in the direct path of the ultrasonic wave. The obtained results confirmed that early crack detection is possible using the developed methodology based on embedded and external sensors and advanced signal processing.


2019 ◽  
Vol 10 (2) ◽  
pp. 251-265 ◽  
Author(s):  
Petr Konrád ◽  
Radoslav Sovják

Research presented in this article is aimed to investigate the ability of ultra-high-performance fibre-reinforced concrete to absorb and dissipate mechanical energy at elevated strain rate loading. Specimens made of ultra-high-performance fibre-reinforced concrete were subjected to the low-velocity impact using the new testing procedure where no fixed supports that hold the sample during the impact were applied. The fibre volume fraction of the ultra-high-performance fibre-reinforced concrete was set as the main test variable in the framework of this study and the volumetric fraction of fibres was ranging from 0.125% to 2%. A high-speed camera was used to measure velocities of the impactor and the ultra-high-performance fibre-reinforced concrete specimen before and after the impact. Consequently, the energy dissipated by the ultra-high-performance fibre-reinforced concrete specimen during the impact was calculated using a simple energy balance equation. To determine the basic material properties of ultra-high-performance fibre-reinforced concrete, quasi-static loading rate was applied and conventional methods were used. A significant difference between the values of dissipated energies for different loading rates and various fibre volumetric fractions was observed. It can be noted that the new procedure shows a reasonable approach for testing the fibre-reinforced cementitious composites under localized impact loading and is worthy of further optimization.


Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 356 ◽  
Author(s):  
Antoine Bassil ◽  
Xin Wang ◽  
Xavier Chapeleau ◽  
Ernst Niederleithinger ◽  
Odile Abraham ◽  
...  

The assessment of Coda Wave Interferometry (CWI) and Distributed Fiber Optics Sensing (DFOS) techniques for the detection of damages in a laboratory size reinforced concrete beam is presented in this paper. The sensitivity of these two novel techniques to micro cracks is discussed and compared to standard traditional sensors. Moreover, the capacity of a DFOS technique to localize cracks and quantify crack openings is also assessed. The results show that the implementation of CWI and DFOS techniques allow the detection of early subtle changes in reinforced concrete structures until crack formation. With their ability to quantify the crack opening, following early detection and localization, DFOS techniques can achieve more effective monitoring of reinforced concrete structures. Contrary to discrete sensors, CWI and DFOS techniques cover larger areas and thus provide more efficient infrastructures asset management and maintenance operations throughout the lifetime of the structure.


Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4031 ◽  
Author(s):  
Hanyu Zhan ◽  
Hanwan Jiang ◽  
Chenxu Zhuang ◽  
Jinquan Zhang ◽  
Ruinian Jiang

This article presents an experimental study of estimating stresses in concrete by applications of coda wave interferometry to establish an acoustoelastic modulus database. Under well-controlled laboratory conditions, uniaxial load cycles were performed on three groups of 15 × 15 × 35-cm concrete prisms, with ultrasonic signals being collected continuously. Then, the coda wave interferometry technique, together with acoustoelastic and Kaiser theories, are utilized to analyze the stress-velocity relations for the distinct ranges before and after historical maximum loads, forming an acoustoelastic modulus database. When applied to different concrete samples, their stresses are estimated with a high degree of accuracy. This study could be used to promote the development of novel nondestructive techniques that aid in structural stress monitoring.


2011 ◽  
Vol 44 (8) ◽  
pp. 728-735 ◽  
Author(s):  
Dennis P. Schurr ◽  
Jin-Yeon Kim ◽  
Karim G. Sabra ◽  
Laurence J. Jacobs

Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localised damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed and recommendations are given for a potential application of CWI in concrete at structural scale.


2016 ◽  
Vol 24 (10) ◽  
pp. e1976 ◽  
Author(s):  
Marcello Serra ◽  
Gaetano Festa ◽  
Maurizio Vassallo ◽  
Aldo Zollo ◽  
Antonino Quattrone ◽  
...  

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