Damage Evaluation Methods Of Structural Members Using Acoustic Emission (Ae) 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. This technique was employed to investigate the process of fracture formation in reinforced concrete and steel structures. In main objective of this research was damage evaluation assessment of reinforced concrete beam and frame as well as welded steel beam specimen, in order to provide a commercial method for the non-destructive evaluation of reinforced concrete and steel structures.A number of reinforced concrete (RC) one story frames and several RC beam specimens with continuous or non-continuous longitudinal rebar were prepared. In addition, several welded steel beam specimens were fabricated. These specimens were tested under loading cycle and were simultaneously monitored using AE technique. The AE test data was analyzed using the number of AE analysis method such as AE source location, b-value analysis method, and damage parameter, Relaxation ratio, Load ratio, Calm ratio and intensity analysis. The trend of these methods during loading and unloading was compared with behaviour of each type of specimens. The results showed that these methods were able to indicate the levels of damage. Also, the results showed that AE can be considered as a viable method to predict the remaining service life of reinforced concrete and steel structure. In addition, with respects to the results obtained from AE analysis, a number of new charts were proposed

Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damagemonitoring in loaded structures. This technique was employed for investigation process of damage in reinforced concrete (RC) frame specimens. A number of reinforced concrete RC frames were tested under loading cycle and were simultaneously monitored using AE.The AE test data were analyzed using the AE source location analysis method. The results showed that AE technique is suitable to identify the sources location of damage in RC structures

Fracture Formation Evaluation of Reinforced Concrete Beam Subjected to Cycle Loading Using Acoustic Emission Technique

Abstract. 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

Investigating the Effect of Lignosulfonate on Erosion Rate of the Embankments Constructed with Clayey Sand

Internal erosion is known as the most important cause of dam failure after overtopping. It is important to improve the erosion resistance of the erodible soil by selecting an effective technique along with the reasonable costs. To prevent internal erosion of embankment dams the use of chemical stabilizers that reduce the soil erodibility potential is highly recommended. In the present study, a lignin-based chemical, known as lignosulfonate, is used to improve the erodibility of clayey sand specimen. The clayey sand was tested in various hydraulic heads in terms of internal erosion in its natural state as well as when it is mixed with the different percentages of lignosulfonate. The results show that erodibility of collected clayey sand is very high and is dramatically reduced by adding lignosulfonate. Adding 3% of lignosulfonate to clayey sand can reduce the coefficient of soil erosion from 0.01020 to 0.000017. It is also found that the qualitative erodibility of stabilized soil with 3% lignosulfonate is altered from the group of extremely rapid to the group of moderately slow