Crack classification in concrete beams using AE parameters (original) (raw)
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Assessing Cracks in Reinforced Concrete Structure Using Acoustic Emission
Acoustic emission (AE) is an important nondestructive evaluation (NDE) technique used in the field of structural engineering. In this study AE technique with a new approach was employed to investigate the process of fracture formation in reinforced concrete structure. A number of reinforced concrete (RC) frames were tested under cyclic load and were simultaneously monitored using AE. The AE test data using intensity analysis method were analyzed. This is based on calculating two values called the historic index (HI) and severity (Sr). The results showed that HI and Sr increase with increasing of loading cycle and trend of HI and Sr showed that these parameters are able to indicate the levels of damage. Also, the results indicated that AE can be considered as a viable method to investigate the process of fracture formation in reinforced concrete structure.
Journal of Civil Structural Health Monitoring, 2013
This article presents an experimental study on variation in acoustic emission (AE) parameters during cracking in reinforced concrete (RC) beams subjected to incremental cyclic loading in laboratory conditions. Nine RC beams with three different span-to-depth ratios ranging from 2.0 to 6.0 with a reinforcement ratio roughly kept the same (1.4-1.5 %) were tested under bending till failure and simultaneously the released AE was recorded. The criteria used to characterize the cracking in RC beams are based on the AE parameters. The AE parameters such as frequency, duration, amplitude, count, rise time, parameters depending on AE signatures such as b-value, and damage parameter D follow the fracture process during the entire loading. The results are useful to distinguish different cracks in RC beams and extend them for field applications.
Fracture Formation Evaluation of Reinforced Concrete Structure Using Acoustic Emission Technique
Acoustic emission (AE) is an important nondestructive evaluation (NDE) technique used in the field of structural engineering for both case local and global monitoring. In this study AE technique with a new approach was employed to investigate the process of fracture formation in reinforced concrete structure. A number of reinforced concrete (RC) one story frames were tested under loading cycle and were simultaneously monitored using AE. The AE test data was analyzed using the relaxation ratio and calm and load ratio method. Also, the relaxation ratio was dominated with approaching load to 58% of the ultimate load. In addition three levels of damage using calm and load ratio were distinguished. The trend of relaxation ratio and calm and load ratio method during loading and unloading showed that these methods are strongly sensitive with cracks growth in RC frame specimens and were able to indicate the levels of damage. Also, results showed that AE can be considered as a viable method to predict the remaining service life of reinforced concrete. In addition, with respect to the results obtained from relaxation ratio and, load and calm ratio indicated, a new chart is proposed.
Acoustic Signal Strength for Damage Evaluation of Reinforced Concrete Beam
2015
Reinforced concrete (RC) structure is a common material used in construction and exposed to excessive load over time. The load would generate cracks in the RC structure and need to be evaluated. This paper presents an acoustic emission (AE) monitoring for damage evaluation of RC beam subjected to increasing fatigue loading. The fatigue loading is subjected on the RC beam based on six loading phases. A total of twelve samples were tested using three-point loading and evaluated using AE signal strength parameter. The AE signal strength is evaluated at flexural region and shear region. Visual crack pattern appeared on the beam surface is also observed. It is found that the AE signal strength to demonstrate the occurrence of crack initiation and propagation in the tested specimen is well matched with the visual observation. Hence, the AE analysis based on signal strength provides valuable information on the occurrence of damage in the RC beam.
Analysis improvements of acoustic emission data in evaluation of concrete beam
2014
Structural health monitoring (SHM) is known as an assessment on damage detection in structural engineering. Nowadays, the application of SHMhas been widely used especially on the continuous real time monitoring system with minimum labour involvement. One of the most excellent tools in SHM for real time monitoring system is an Acoustic Emission (AE). AE waves are high frequency stress wave generated by rapid release of energy from localised sources within a material, such as crack initiation and growth. High sensitivity to crack growth, the ability to locate source, passive nature and the possibility to perform real time monitoring are some of the attractive features of AE technique. In spite of these advantages, challenges still exist in using AE technique for monitoring applications especially in analysing recorded AE data as large volume of data are usually generated during monitoring.In this research works, AE parameter, which are Signal Strength and Absolute Energy were selected...
Acoustic emission for damage characterization of reinforced concrete beams
2015
This article reports on acoustic emission (AE) used to monitor the fracture process in reinforced concrete (RC) beams subjected to cyclic loading. Influence of loading rate on variation in AE based b-values with the development of cracks are studied. RC beams of length 3.2 m were tested under load control at a rate of 4 kN/s, 5 kN/s and 6 kN/s and simultaneously, the released AE signals were recorded. Aim of the present work was to use the AE based b-value analysis available in seismology, to characterize the damage in RC structures. It was observed that when the loading rate is faster, then the quick cracking development lead to rapid fluctuations and drops in the bvalue. At higher loading rates (or in higher strain rates), the b-values are lower in average as a few and strong cracking AE events are created, in contrast to more and weaker at low loading rate. The results show that AE technique is useful to study the fracture process in concrete structures.
Acoustic emission (AE) technique is one of the non-destructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring in loaded structures. In present study, AE technique with a new approach was employed to investigate the process of fracture formation in reinforced concrete (RC) structure. Thirty RC beam specimens with continuous and non-continuous longitudinal rebar were prepared. The RC beams were tested under loading cycle and were simultaneously monitored using AE. The AE test data was analyzed using Relaxation, Load and Calm ratio. The trend of these methods during loading and unloading was compared with behaviour of each type of specimens. The trend of Relaxation ratio and Calm and Load ratio method during loading and unloading showed that these methods are strongly sensitive with cracks growth in RC beam specimens and were able to indicate the levels of damage. Also, results showed that AE can be considered as a viable method to predict the remaining service life of reinforced concrete. In addition, with respects to the results obtained from Relaxation, Load and Calm ratio indicated, a new chart is proposed.
Crack Localization in Reinforced Concrete Beam by Acoustic Emission Technique
International Conference on Civil and Enviromental Engineering, 8-10 May 2017, Cappadocia, Nevsehir, Turkey, 2017
Predetermining of failure sources for safety of the structures is a significant and demanding issue. There are several damage assessment methods to overcome this problem. Most of these techniques generally investigate damaged status of the structure and need sampling. However, it is important to identify the current state and safety of the structure before the damage becomes visible. Nondestructive methods circumvent this problem and provide an opportunity to monitor the damage without any harming. Acoustic Emission (AE) is one of the nondestructive testing methods and provides to monitor fracture processes even at low load levels. The technique bases on propagation and detection of elastic waves generated by energy discharging due to failure. By this means, it is possible to determine location, time of origin and propagation of fracture sources in material by AE. In this study, a reinforced concrete beam was tested under cyclic loading and monitored by AE. Afterwards, AE data obtained from the test was processed, a specific localization algorithm was applied to the data and cracks of the beams were localized. Thus, invisible crack propagation of reinforced concrete beam was revealed by AE source localization technique.
Damage Assessment Reinforced Concrete Beams Using Acoustic Emission Technique
2011
Reinforced concrete (RC) beams were tested under incremental cyclic loading and simultaneously acoustic emissions (AE) were recorded. The analysis of the AE released was carried out by using parameters namely relaxation ratio, load ratio and calm ratio. Digital image correlation (DIC) technique was used to measure the surface displacement and strains in concrete. Earlier researchers classified the damage in the RC beams using Kaiser effect of AE, crack mouth opening displacement (CMOD) and proposed a standard (NDIS-2421: The Japanese Society for Non-Destructive Inspection (JSNDI)). In general, multiple cracks take place in RC beams under bending. In the present study the damage in RC beams was classified on the basis of limit state of serviceability specified by the code of practice IS456:2000, AE based parameters. Coupling between AE technique and DIC experimental technique may give useful information on the state of damage of RC beams.
2011
Concretes structures have been facing several types of damage mechanisms during their lifetime. The types of common defects in concretes structures are crack formations, corrosion, scalling, and etc. Therefore, an evaluation method such as acoustic emission (AE) is required for assessing the deterioration on concretes structures. This paper provides a brief discussion on the evaluations of the acoustic emission signal strength to the health monitoring of reinforced concrete structures beams. Small scale size beam has been used for this investigation and the AE signal processing is the main principal data in this work for assessing by using the statistical quantitative technique, which is known as intensity analysis (IA).This type of technique is able to quantify and evaluate the damage severity on concretes structures. Eventually, the results presented in this research using AE signal strength are greater parameter in determining the micro and macro cracking and also the damage mechanism level on concretes structures.