Acoustic emission monitoring and quantitative evaluation of damage in reinforced concrete members and bridges

A considerable proportion of highway bridges in the US, are made of reinforced concrete. The vulnerability of these structures during their long service life is a cause of major concern for civil engineers. Since there is a need to detect and recuperate the condition of the bridge structures numerous innovative non-destructive testing (NDT) techniques have come into the forefront. Of the many available technologies, acoustic emission (AE) monitoring has been the most popular non-destructive technique used on highway bridges. Acoustic emission is a passive monitoring technique. Thus, it can be appropriately used for field bridge monitoring applications. Usually AE monitoring is used to obtain qualitative results by observing the trends of the conventional AE parameters recorded by the data acquisition system. The extent of damage is then determined using other NDT techniques. The current study aims at applying the intensity analysis technique of damage quantification to conventional AE parameters generated from reinforced concrete members. A few reinforced concrete beams are subjected to varied cyclic load patterns in the laboratory to study the trends that may be observed in the intensity chart during damage propagation. The results thus obtained are then compared to other prevalent damage assessment techniques as well. Additionally, AE data collected from two field bridge tests are also subjected to intensity analysis technique of damage quantification to evaluate the practical viability of the technique in assessing the severity of the damage in the monitored structures

Damage monitoring in fibre reinforced mortar by combined digital image correlation and acoustic emission

International audienceThe present work aims at developing a methodology for the detection and monitoring of damage and fractures in building materials in the prospects of energetic renovation. Digital image correlation (DIC) and acoustic emission (AE) monitoring were simultaneously performed during tensile loading tests of fibre reinforced mortar samples. The full-field displacement mappings obtained by DIC revealed all ranges of cracks, from microscopic to macroscopic, and an image processing procedure was conducted as to quantify their evolution in the course of the degradation of the samples. The comparison of these measurements with the acoustic activity of the material showed a fair match in terms of quantification and localisation of damage. It is shown that after such a calibration procedure, AE monitoring can be autonomously used for the characterisation of damage and fractures at larger scales

A review on acoustic emission monitoring for damage detection in masonry structures

Acoustic emission monitoring is widely used for damage detection in materials research and for site monitoring. Its use for masonry structures is however challenging due to the highly heterogenic nature of masonry and rapid signal attenuation. However, the non-invasive nature and high sensitivity of the technique also provide interesting opportunities, especially for historical masonry structures, to locate damage, identify severity of damage and rate of deterioration. Aim of this paper is to provide an extensive literature review on the application of the acoustic emission technique for masonry structures, addressing specific challenges and recent findings. AE-based methods for damage assessment in masonry are discussed in view of monitoring approaches, wave propagation, source location and crack development under static, fatigue and creep loading. Site applications are discussed for identifying crack location and crack propagation in historical masonry towers, buildings and masonry arch bridges. The paper concludes with future challenges identified in this research field

Structural Health Monitoring of Large Structures Using Acoustic Emission-Case Histories

Acoustic emission (AE) techniques have successfully been used for assuring the structural integrity of large rocket motorcases since 1963 [...

A Novel Damage Index for Online Monitoring of RC Slabs under Monotonic Loading by Integration of Process Controlling into Acoustic Emission Technique

This study introduces a novel structural health monitoring scheme for cementitious composite slabs with the aid of acoustic emission (AE) technique coupled with statistical process controlling (SPC) method. The adopted framework is an integrated monitoring solution that effectively relates current state (damaged) to reference state of the structure. Evaluation of the latter was made possible using autoregressive model incorporating a set of damage-sensitive feature. In order to provide a benchmark damage indicator, the collected data were processed using control chart analysis. The damage indicators for the former was similarly obtained and then compared with the benchmark to gauge the structural damage. These control charts offer a robust framework meticulously identifying inconsistency in the damage-sensitive feature imposed over the monitoring period. Linear and quadratic projections were also incorporated into SPC model to enhance identification of system transition to other damage states

Monitoring and analysis of reinforced concrete plate-column structure under room temperature and fire based on acoustic emission

This paper attempts to disclose the damage mechanism of reinforced concrete plate-column structure under room temperature and fire. Several tests were carried out to record the law of crack development on the plate surface under room temperature. The infrared detection technology was adopted to observe how cracks develop under fire. The acoustic emission (AE) signals at different positions of the specimen were monitored by the AE techniques. Coupled with the macroscopic test phenomena, several characteristic parameters collected by the AE system, namely, cumulative number of events, event rate, energy rate and b-value, were analyzed in details. The results show that: the cumulative number of events was active in the loading, heating and cooling stages; the crack density and the change of internal forces could be derived from the trend of event rate; the local energy changes of the specimen could be deciphered from the curves of energy rate and b-value, making it possible to judge if a component has reached the failure state; the specimen suffered the most severe damages, when the AE parameters suddenly changed; AE monitoring enables the early warning of fire to reinforced concrete plate-column structure; infrared detection technology is suitable for real-time monitoring of crack development under high temperature.      &nbsp

Crack monitoring in historical masonry with distributed strain and acoustic emission sensing techniques

The analysis of crack patterns and crack growth is one of the most important steps in the assessment of structural damage in historical masonry. In a search for integrated and accurate monitoring techniques for crack measurements in masonry, several novel techniques based on distributed strain monitoring and acoustic emission (AE) sensing have been investigated in an experimental test campaign. Aim of the test program was to develop integration procedures for the strain and AE sensors, analyse their use for crack monitoring specifically in historical masonry and assess their robustness and efficiency with respect to the experimentally observed crack pattern.This work is performed within the framework of the GEPATAR project (“GEotechnical and Patrimonial Archives Toolbox for ARchitectural conservation in Belgium” BR/132/A6/GEPATAR), which is financially supported by BRAIN-be, Belspo.Postprint (updated version