scholarly journals Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2199 ◽  
Author(s):  
Beata Zima
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Wave Velocity ◽  
Guided Waves ◽  
Concrete Structures ◽  
Circular Cross Section ◽  
Guided Wave ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Average Wave

The following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete specimens with varying extents of debonding damage by piezoelectric sensors attached at both ends of the beams. Experimental results in the form of time–domain signals registered for variable extent of debonding were compared, and the relationships relating to the damage size and time of flight and average wave velocity were proposed. The experimental results were compared with theoretical predictions based on dispersion curves traced for the free rod of circular cross-section and rectangular reinforced concrete cross-section. The high agreement of theoretical and experimental data proved that the proposed method, taking advantage of average wave velocity, can be efficiently used for assessing debonding size in reinforced concrete structures. It was shown that the development of damage size in circumferential direction has a completely different impact on wave velocity than development of debonding length. The article contains a continuation of work previously conducted on the detection of delamination in concrete structures. The proposed relationship is the next essential step for developing a diagnostics method for detecting debondings of any size and orientation.

scholarly journals Assessing the Instantaneous Stiffness of Cracked Reinforced Concrete Beams Based on a Gradual Change in Strain Distributions

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chunyu Fu ◽  
Dawei Tong ◽  
Yuyang Wang
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beams ◽  
Internal Force ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Gradual Change ◽  
Concrete Cracking ◽  
Good Agreement

Concrete cracking causes a gradual change in strain distributions along the cross section height of reinforced concrete beams, which will finally affect their instantaneous stiffness. A method for assessing the stiffness is proposed based on the gradual change, which is considered through modeling different strain distributions for key sections in cracked regions. Internal force equilibria are adopted to find a solution to top strains and neutral axes in the models, and then the inertias of the key sections are calculated to assess the beam stiffness. The proposed method has been validated using experimental results obtained from tests on five reinforced concrete beams. The predicted stiffness and displacements are shown to provide a good agreement with experimental data. The instantaneous stiffness is proven to greatly depend on the crack number and depth. This dependence can be exactly reflected by the proposed method through simulating the gradual change in concrete strain distributions.

Experimental Study on Reinforcement of Failure Reinforced Concrete Beams

2013 ◽  
Vol 275-277 ◽  
pp. 1264-1267
Author(s):  
Qian Chen ◽  
Ling Yong Liu ◽  
Yang Jun Meng
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Epoxy Resin ◽  
Cross Section ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Carbon Cloth ◽  
Structural Failure

Through repair and reinforcement of breaking reinforced concrete beams by epoxy resin and carbon cloth, and its experiment, the crack and deformation and bearing capacity as well as ductility of such beams are obtained. Experimental results show that the ultimate bearing capacity of beams after reinforcement increased by 210%, the structure ductility fell by 170%, structural failure form is similar to failure in normal cross section.

scholarly journals Debonding Size Estimation in Reinforced Concrete Beams Using Guided Wave-Based Method

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 389 ◽  
Author(s):  
Beata Zima ◽  
Rafał Kędra
Keyword(s):  
Reinforced Concrete ◽  
Guided Waves ◽  
Concrete Beams ◽  
Load Capacity ◽  
Experimental Tests ◽  
Concrete Cover ◽  
Guided Wave ◽  
Reinforced Concrete Beams ◽  
Size Estimation ◽  
Advantages And Disadvantages

The following paper presents the results of the theoretical and experimental analysis of the influence of debonding size on guided wave propagation in reinforced concrete beams. The main aim of the paper is a development of a novel, baseline-free method for determining the total area of debonding between steel rebar embedded in a concrete cover on the basis of the average wave velocity or the time of flight. The correctness of the developed relationships was verified during the experimental tests, which included propagation of guided waves in concrete beams with the varying debonding size, shape and location. The analysis of the collected results proved that guided waves can be efficiently used not only in the debonding detection, but also in an exact determining of its total area, which is extremely important in the context of the nondestructive assessment of the load capacity of the reinforced concrete structures. The undeniable advantage of the proposed method is that there are no requirements for any baseline signals collected for an undamaged structure. The paper comprises of the detailed step by step algorithm description and a discussion of both the advantages and disadvantages.

scholarly journals Guided Wave Inspection of Bars in Reinforced-Concrete Beams Using Surface-Mounted Vibration Sensors

Vibration ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 343-356
Author(s):  
Evelyne El Masri ◽  
Timothy Waters ◽  
Neil Ferguson
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Reflection Coefficient ◽  
Guided Waves ◽  
Transfer Functions ◽  
Concrete Beams ◽  
Guided Wave ◽  
Reinforced Concrete Beams ◽  
Invasive Technique ◽  
Reflection Coefficients

Steel reinforcement bars (rebars) in concrete structures are inaccessible and not conducive to many inspection methods. This paper proposes a non-invasive technique based on guided waves for detecting localised abnormalities in rebars embedded in concrete beams. The technique is predicated on previously published observations that guided waves are strongly reflected by discontinuities at the frequency at which they begin to propagate, i.e., at cut-on. The reflection coefficient at cut-on is estimated using a simple wave decomposition in which a near-zero wavenumber value is assumed. A simulated study is first carried out to evaluate the technique on a concrete beam featuring four rebars. The wave finite element approach is adopted to model two uniform beams which are coupled via a short, damaged section modelled in conventional finite element analysis. Estimated reflection coefficients arising from the discontinuity are close to the true values at cut-on and independent of frequency elsewhere, so that no prior knowledge of cut-on frequencies is required. Three steel-reinforced concrete beams were fabricated—one uniform and two with localised rebar damage—and reflection coefficients were estimated from measured transfer functions. As predicted, abrupt deviations in the reflection coefficient occurred at cut-on frequencies for both damaged beams.

scholarly journals BENDING WITH TORSION OF FIBER REINFORCED CONCRETE BEAM OF CIRCULAR CROSS SECTION

2021 ◽  
Vol 17 (3) ◽  
pp. 173-181
Author(s):  
Sergey Bulkin
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
High Strength Steel ◽  
Circular Cross Section ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
The Moment

The article provides information about the tests of circle cross-section reinforced concrete beams made of high-strength steel-fiberconcrete on combined torsion and bending. Given information contains the main results: a diagram of the cracks with an indication of their opening width, the values of support reactions at the moment of cracking and at the moment before destruction. It was found that as the load is applied in beams made of high-strength steel-reinforced concrete, in the case of several cracks at the firststage, there is one crack increases. The beams are modeled in the design complex and given description of the main design parameters. The results of the calculation are presented and a comparative analysis of the results obtained with the experiments results. It is noted that the adopted models in the computational complexes require the development of subroutines and refinement

scholarly journals CRITICAL DEPTH OF NORMAL CRACKS IN REINFORCED CONCRETE BEAMS OF RECTANGULAR CROSS-SECTION

2013 ◽  
Vol 19 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Vidmantas Jokūbaitis ◽  
Linas Juknevičius
Keyword(s):  
Reinforced Concrete ◽  
Stress State ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Analytical Data ◽  
Concrete Structures ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Concrete Members ◽  
Section Shape

The evaluation of stress state of longitudinal tensile reinforcement is highly important while examining the technical state of under-reinforced concrete structures. The appearance of yield stress in tensile reinforcement could be treated as the start of incipient failure of the flexural structure. The state of tensile reinforcement of flexural reinforced concrete structures could be examined by observing the properties of normal cracks. This paper presents the analysis of the relationship between various parameters of a normal crack during its development. Some elements of fracture mechanics are used for analysis of stress state in flexural reinforced concrete members. The analytical data are compared to the experimental results, and the adjustment functions are proposed for flexural beams of certain cross section shape, dimensions and reinforcing ratio.

Identification of incipient pitting corrosion in reinforced concrete structures using guided waves and piezoelectric wafer transducers

2018 ◽  
Vol 18 (1) ◽  
pp. 164-171 ◽  
Author(s):  
Rajeshwara Chary Sriramadasu ◽  
Ye Lu ◽  
Sauvik Banerjee
Keyword(s):  
Reinforced Concrete ◽  
Pitting Corrosion ◽  
Guided Waves ◽  
Concrete Structures ◽  
Guided Wave ◽  
Reinforced Concrete Structures ◽  
Destructive Testing ◽  
Piezoelectric Wafer ◽  
Non Destructive ◽  
Diameter Reduction

Corrosion poses a great threat to ageing civil infrastructure in the world, and researchers are seeking methods to monitor the corrosion in reinforced concrete structures. Detection of corrosion at its incipient stage has been an impending task in the non-destructive testing of materials. Several non-destructive testing methods to assess the presence of corrosion exist. The limitation of the current methods is that either they require measurement at several points or they require a large network of sensors. Guided wave-based monitoring overcomes these limitations because a large area can be scanned using fewer sensors. The process of corrosion is complex, and it leads to a simultaneous reduction in the diameter and the debonding between concrete and reinforcing steel bars in reinforced concrete structures. However, some of the recent studies that explore the use of guided waves focus only on the detection of the individual effect of diameter reduction and debonding of the rebars in reinforced concrete by artificially inducing the damage. In this study, an accelerated corrosion setup is deployed to induce pitting corrosion in reinforced concrete beams using the impressed current method. These beams are continuously monitored using ultrasonic guided waves that are generated and received by piezoelectric wafer transducers that are attached to the rebars. It is shown that the incipient stage of pitting corrosion can be detected successfully, and the mechanism of corrosion process, which involves the corrosion initiation, progression, and diameter reduction-and-cracking phases, can be established from the signal characteristics of the longitudinal and flexural-guided wave modes. The impressed current flow in the corrosion cell also confirms the various phases of corrosion.

Experimental Study on Reinforcement of Failure Reinforced Concrete Beams

2014 ◽  
Vol 578-579 ◽  
pp. 1266-1270
Author(s):  
Qiang Chen ◽  
Ling Yong Liu ◽  
Yang Jun Meng
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Epoxy Resin ◽  
Cross Section ◽  
Concrete Beams ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Carbon Cloth ◽  
Structural Failure

Through repair and reinforcement of breaking reinforced concrete beams by epoxy resin and carbon cloth, and its experiment, the crack and deformation and bearing capacity as well as ductility of such beams are obtained. Experimental results show that the ultimate bearing capacity of beams after reinforcement increased by 210%, the structure ductility fell by 170%, structural failure form is similar to failure in normal cross section.

scholarly journals Main results of experimental studies of reinforced concrete structures of high-strength concrete B100 round and circular cross sections in torsion with bending

2019 ◽  
Vol 15 (1) ◽  
pp. 51-61
Author(s):  
Vladimir I Travush ◽  
Nikolay I Karpenko ◽  
Vladimir I Kolchunov ◽  
Semen S Kaprielov ◽  
Alexey I Dem’yanov ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
High Strength Concrete ◽  
Crack Opening ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Circular Cross Section ◽  
High Strength ◽  
Reinforced Concrete Structures ◽  
Strength Concrete

Aim of the research to verify the proposed calculating apparatus and accumulate new experimental data on the complex resistance of reinforced concrete structures, experimental studies of such structures made of high-strength concrete of circular and circular cross-section were conducted at the testing base of the South-West State University. Method is experimental-theoretical. Results of experimental research the plots of the deflections and rotation angles, the dependency of deformations of concrete according to the testimony of the outlets of electrodesorption with respect to the calculated cross section 1-1. The main deformations of elongation and shortening of concrete were determined; the reinforcement was selected in such a way that in the stage preceding the destruction, it reached fluidity, so the stresses in the reinforcement are known. It is established that for reinforced concrete structures made of high-strength concrete of circular cross-section, as a rule, there is the development of two cracks, i.e. the round shape of the cross-section slightly reduces the concentration due to the structure of high-strength concrete. For the annular section there were several cracks, of which stands out the one on which the destruction occurs. On the steps preceding the destruction, this crack begins to prevail over the rest and has a maximum opening width. On the basis of experimental studies of reinforced concrete structures made of high-strength concrete of square and box sections, reliable data on the complex stress-strain state in the studied areas of resistance, such as: the values of the generalized load of cracking , and destruction ,, its level relative to the limit load; the distance between the cracks at different levels of cracking (up to the moment of destruction, as a rule, two or three levels are formed); crack widths at the level of the axis of the working armature, at a distance of two diameters from the axes of the armature and along the entire crack profile at various stages of loading, from which it follows that the crack opening at the level of the axis of reinforcement in 2-3 times less compared with the crack opening on the removal of 1.5-2 diameters of the working axis (longitudinal and transverse) reinforcement; the coordinates of the spatial formation of cracks; schematic drawings on tablets of education, development and opening of cracks of reinforced concrete constructions in torsion with bending. Thus, the experimental studies and the result provide an opportunity to test the developed computational model and its working hypotheses for assessing the resistance of reinforced concrete structures made of high-strength concrete in torsion with bending.

Sign in / Sign up

Export Citation Format

Share Document