scholarly journals Early Crack Detection of Reinforced Concrete Structure Using Embedded Sensors

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3879 ◽  
Author(s):  
Joyraj Chakraborty ◽  
Andrzej Katunin ◽  
Piotr Klikowicz ◽  
Marek Salamak
Keyword(s):  
Reinforced Concrete ◽  
Crack Detection ◽  
Structural Condition ◽  
Probability Of Detection ◽  
Embedded Sensors ◽  
Bending Test ◽  
Reinforced Concrete Structure ◽  
Destructive Testing ◽  
Rc Structures ◽  
Ultrasonic Signals

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.

scholarly journals Damage Source Identification of Reinforced Concrete Structure Using Acoustic Emission Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Alireza Panjsetooni ◽  
Norazura Muhamad Bunnori ◽  
Amir Hossein Vakili
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Nondestructive Evaluation ◽  
Analysis Method ◽  
Reinforced Concrete Structure ◽  
Acoustic Emission Technique ◽  
Rc Structures ◽  
Rc Frames ◽  
Damage Monitoring ◽  
Investigation Process

Acoustic emission (AE) technique is one of the nondestructive evaluation (NDE) techniques that have been considered as the prime candidate for structural health and damage monitoring 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.

scholarly journals Strengthening of Concrete Element with Precast Textile Reinforced Concrete Panel and Grouting Material

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3856
Author(s):  
Young-Jun You ◽  
Hyeong-Yeol Kim ◽  
Gum-Sung Ryu ◽  
Kyung-Taek Koh ◽  
Gi-Hong Ahn ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Bending Test ◽  
Strengthening Effect ◽  
Textile Reinforced Concrete ◽  
Concrete Element ◽  
Rc Structures ◽  
Flexural Strengthening ◽  
Grouting Material ◽  
Rc Slab ◽  
Rc Slabs

Textile reinforced concrete (TRC) has widely been used for strengthening work for deteriorated reinforced concrete (RC) structures. The structural strengthening often requires accelerated construction with the aid of precast or prefabricated elements. This study presents an innovative method to strengthen an RC slab-type element in flexure using a precast panel made of carbon TRC. A total of five RC slabs were fabricated to examine the flexural strengthening effect. Two of them were strengthened with the precast panel and grouting material and another set of two slabs was additionally strengthened by tensile steel reinforcement. The full-scale slab specimens were tested by a three-point bending test and the test results were compared with the theoretical solutions. The results revealed that the ultimate load of the specimens strengthened with the TRC panel increased by at least 1.5 times compared to that of the unstrengthened specimen. The application of the precast TRC panel and grouting material for the strengthening of a prototype RC structure verified its outstanding constructability.

scholarly journals A Crack Characterization Method for Reinforced Concrete Beams Using an Acoustic Emission Technique

2020 ◽  
Vol 10 (21) ◽  
pp. 7918 ◽  
Author(s):  
Md Arafat Habib ◽  
Cheol Hong Kim ◽  
Jong-Myon Kim
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Crack Detection ◽  
Concrete Beams ◽  
Time History ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
K Nearest Neighbor ◽  
Micro Cracks ◽  
Ae Signals

This study aims at characterizing crack types for reinforced concrete beams through the use of acoustic emission burst (AEB) features. The study includes developing a solid crack assessment indicator (CAI) accompanied by a crack detection method using the k-nearest neighbor (k-NN) algorithm that can successfully distinguish among the normal condition, micro-cracks, and macro-cracks (fractures) of concrete beam test specimens. Reinforced concrete (RC) beams undergo a three-point bending test, from which acoustic emission (AE) signals are recorded for further processing. From the recorded AE signals, crucial AEB features like the rise time, decay time, peak amplitude, AE energy, AE counts, etc. are extracted. The Boruta-Mahalanobis system (BMS) is utilized to fuse these features to provide us with a comprehensive and reliable CAI. The noise from the CAI is removed using the cumulative sum (CUMSUM) algorithm, and the final CAI plot is used to classify the three different conditions: normal, micro-cracks, and fractures using k-NN. The proposed method not only for the first time uses the entire time history to create a reliable CAI, but it can meticulously distinguish between micro-cracks and fractures, which previous works failed to deal with in a precise manner. Results obtained from the experiments display that the CAI built upon AEB features and BMS can detect cracks occurring in early stages, along with the gradually increasing damage in the beams. It also soundly outperforms the existing method by achieving an accuracy (classification) of 99.61%, which is 17.61% higher than the previously conducted research.

Risk Assessment of Reinforced Concrete Structure Attacked by Chloride

2011 ◽  
Vol 217-218 ◽  
pp. 734-739 ◽  
Author(s):  
Chongsin Sookoomjariyapong ◽  
Sanguan Vongchavalitkul ◽  
Sun Sayamipuk
Keyword(s):  
Risk Assessment ◽  
Reinforced Concrete ◽  
Concrete Structure ◽  
Structural Engineering ◽  
Risk Index ◽  
Structural Condition ◽  
Actual Condition ◽  
Reinforced Concrete Structure ◽  
Extreme Risk ◽  
Chloride Attack

The deterioration of reinforced concrete (RC) structure due to chloride attack plays an important role in the reduction of structure strength. Consequently, the actual condition of structure is an essential investigation for management planning in concrete structure which is attacked by chloride. In this paper, the proposed assessment bases on the risk management and the reliability theory presents in risk index (RI) of structure. The reinforced concrete building under the marine environment was an illustrative example for risk evaluation. It was found that the risk index of structure equaled to 20, it implied that the structural condition encountered with extreme risk due to chloride attack and must be rehabilitated urgently. As analysis results, the risk assessment is relation to the actual condition of structure. This assessment can be used as a guideline tool for structural engineering to assess the concrete structure attacked by chloride.

scholarly journals Forensic to the Reinforced Concrete (RC) Structures at Library

2020 ◽  
Vol 19 (1) ◽  
pp. 6-14
Author(s):  
Tang Hing Kwong ◽  
Rudy Tawie ◽  
Siti Rozana Romali
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Concrete Strength ◽  
Reinforced Concrete Beam ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structure ◽  
Rebound Hammer ◽  
Rc Structures ◽  
Three Samples ◽  
Eurocode 2

This Forensic project has been proposed to investigate the reinforced concrete structure defect at library. There were found 65 points cracks and 20 points spalling in library such as only at reinforced concrete beam and slab part in first floor. The total of cracks which crack width less than 0.25 mm is 63 points and the crack width between 0.25 mm to 5.00 mm is 2 points only. These cracks had categorized as fine cracks because the crack width not more than 5 mm. There was 21 samples Rebound Hammer test was random measured the existing concrete compressive strength of critical structures which six samples at beams, six samples at slabs, six samples at columns and three samples at staircase in library. The Rebound Hammer test shown that average mid-point strength at beam is 33 N/mm2, slab is 25 N/mm², column is 38 N/mm2 and staircase is 37 N/mm2 . Based on the Eurocode 2, the minimum grade concrete required is 25N/mm2 to do the design for reinforced concrete structures, which all the existing concrete strength were achieved the minimum concrete strength. Finally, the Orion software are used to analysis and determine the size of steel reinforcement, the design found the required bar size of steel reinforcement at the middle span or continuous support is 2T16 & 2T25 or 2T20 & 2T25 but the existing steel reinforcement is 2T12 and 2T20 which the existing steel reinforcement could not be sustained the big loading that applied on the library.

Analytical Study on Dynamic Response of Reinforced Concrete Structure With Internal Equipment Subjected to Projectile Impact

2020 ◽  
Author(s):  
Yukihiko Okuda ◽  
Zuoyi Kang ◽  
Akemi Nishida ◽  
Haruji Tsubota ◽  
Yinsheng Li
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Stress Waves ◽  
Dynamic Responses ◽  
Stress Wave Propagation ◽  
Reinforced Concrete Structure ◽  
Energy Agency ◽  
Rc Structures ◽  
Projectile Impact ◽  
Reactor Building

Abstract In case of a projectile impact on a reactor building of a nuclear power plant, stress waves propagate from the impacted wall to the structure’s interior. It is important to assess the effect of dynamic responses generated by the projectile’s impact on internal equipment, because stress waves are likely to excite high-frequency vibrations of internal equipment. The OECD (Organization for Economic Co-operation and Development) / NEA (Nuclear Energy Agency) launched the IRIS (Improving Robustness Assessment Methodologies for Structures Impacted by Projectiles) benchmark project in order to assess the dynamic response of a nuclear facility to projectile impact, and the third phase of IRIS (IRIS 3) [1] contributes to the investigation of the dynamic responses of reinforced concrete (RC) structures that house internal equipment. We have participated in IRIS 3 and have performed calibration analyses of projectile impact tests on a structure that models a reactor building that houses internal equipment. Specifically, we have developed and validated a numerical approach to investigation of impact responses of an RC structure that houses internal equipment through calibration correction. This paper presents partial simulation results of the dynamic responses of this structure and discusses the effects of support conditions of the internal equipment and stress wave propagation.

scholarly journals Reliability analysis of non-destructive testing models within a probabilistic approach

2019 ◽  
Vol 281 ◽  
pp. 04003
Author(s):  
Wafaa Abdallah ◽  
Jacqueline Saliba ◽  
Ziubir-Mehdi Sbartaï ◽  
Marwan Sadek ◽  
Fadi Hage Chehade ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Probabilistic Approach ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Reinforced Concrete Structure ◽  
Destructive Testing ◽  
Engineering Structures ◽  
Conversion Model ◽  
Observable Variable

The diagnosis of reinforced concrete is essential to detect the degradation and thus maintain the structural performance of civil engineering structures. This paper aims to establish a mathematical relationship between the ultrasonic pulse velocity UPV (considered as an observable variable) and two concrete properties indicators (compressive strength fc and water content W) within a probabilistic framework. Synthetic simulations are proposed to derive a conversion model between the statistical properties of the output and the input parameters for a reinforced concrete structure by taking into account spatial variability of concrete.

scholarly journals Crack Detection of Reinforced Concrete Member Using Rayleigh-Based Distributed Optic Fiber Strain Sensing System

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Tingjin Liu ◽  
Honghao Huang ◽  
Yubing Yang
Keyword(s):  
Reinforced Concrete ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Crack Detection ◽  
Concrete Surface ◽  
Strain Sensing ◽  
Rc Structures ◽  
Strain Measurements ◽  
Space Resolution ◽  
Sensing System

Early detection of crack is critical for the maintenance of reinforced concrete (RC) structures. In this study, a distributed optical fiber (DOF) sensing system with Rayleigh Optical Frequency Domain Reflectometry (OFDR) technique was deployed to a member of RC structure in a full-scale laboratory experiment, which was subjected to a monotonic lateral load. With the aid of a high space resolution (up to 1 mm) and measurement accuracy (±1 micro strain) interrogator (OSI-S by Semicon), continuous strain measurements inside of the RC member are elaborately implemented. The result of crack detection by the analysis of the measured tensile strain profiles is in excellent agreement with the visually observable cracks mapped during the test. This confirms the ability of the optical fiber inside of RC members to capture cracks on concrete surface. Moreover, the recognition of crack orientation and depth is accomplished by comparing strain measurements of optical fibers installed at multiple locations.

Random Analysis of RC Structures during Construction

2011 ◽  
Vol 105-107 ◽  
pp. 981-985
Author(s):  
Jun Zhao ◽  
Wei Wei Jia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Structure ◽  
Stochastic Finite Element Method ◽  
Reinforced Concrete Structure ◽  
Stochastic Finite Element ◽  
Rc Structures ◽  
Stability Of Structures ◽  
Element Method

Since accidents of reinforced concrete structure occur frequently, it is a key issue to ensure the safety and stability of structures during construction. In this paper, each construction cycle was divided into four stages using discrete time method of freezing to establish the computational model. According to random theory, with the characteristics of reinforced concrete structures during construction, a series of recurrence equation is built by stochastic finite element method during construction. Based on a random analysis of practical engineering, the random response time-varying rule of reinforced concrete structure is obtained during construction. The results show that the construction process of reinforced concrete structure could be simulated well based on perturbation stochastic finite element method .Both the mean and standard deviation of deflection of mid-span could be obtained precisely.

scholarly journals Temperature Stress Analysis of Super-Long Frame Structures Accounting for Differences in the Linear Expansion Coefficients of Steel and Concrete

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1519
Author(s):  
Yigang Jia ◽  
Liangjian Lu ◽  
Guangyu Wu ◽  
Bo Zhang ◽  
Huibin Wang
Keyword(s):  
Reinforced Concrete ◽  
Stress Analysis ◽  
Temperature Stress ◽  
Linear Expansion ◽  
Frame Structures ◽  
Reinforced Concrete Structure ◽  
Rc Structures ◽  
Design Elements ◽  
Expansion Coefficients ◽  
The Difference

Temperature stress analysis is of prime importance to ensure the adequate servicing of super-long frame structures during their service life. The existing design codes and recommendations for reinforced concrete (RC) structures provide methodologies for the reinforcement of design elements that neglect differences in the linear expansion coefficients of steel and concrete. In this paper, we present a numerical method based on a degenerated three-dimensional solid virtual laminated element for simulating and analyzing the temperature stress of a two-layer super-long frame reinforced concrete structure subjected to allover cooling action, whereby the difference in the linear expansion coefficients of steel and concrete are taken into consideration. The results show that the difference in the linear expansion coefficients of steel and concrete, with different constraints, affects the temperature stress experienced by each material in the structure, and this difference adversely affects attempts to avoid structure cracking.

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