Damage detection in rebar-reinforced concrete beams based on time reversal of guided waves

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.

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

Vibration ◽

10.3390/vibration3040023 ◽

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.

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Damage Detection of Reinforced Concrete Beams with Novel Distributed Crack/Strain Sensors

Structural Health Monitoring ◽

10.1177/1475921704045625 ◽

2004 ◽

Vol 3 (3) ◽

pp. 225-243 ◽

Cited By ~ 29

Author(s):

Genda Chen ◽

Huimin Mu ◽

David Pommerenke ◽

James L. Drewniak

Keyword(s):

Reinforced Concrete ◽

Damage Detection ◽

Concrete Beams ◽

Strain Sensors ◽

Reinforced Concrete Beams

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Advanced Signal Processing Techniques for Damage Detection in Reinforced Concrete Beams

Lecture Notes in Civil Engineering - Advances in Construction Materials and Structures ◽

10.1007/978-981-15-9162-4_8 ◽

2021 ◽

pp. 87-100

Author(s):

S. Kavitha ◽

K. Sumangala ◽

R. Joseph Daniel ◽

S. Rajakumar

Keyword(s):

Signal Processing ◽

Reinforced Concrete ◽

Damage Detection ◽

Concrete Beams ◽

Reinforced Concrete Beams ◽

Processing Techniques ◽

Signal Processing Techniques

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Strain Mode Damage Detection in Reinforced Concrete Beams Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.566 ◽

2012 ◽

Vol 446-449 ◽

pp. 566-571

Author(s):

Jia Quan Wu ◽

Ji Yao ◽

Hong Yan Li ◽

Liang Cao ◽

Kun Ma

Keyword(s):

Finite Element ◽

Reinforced Concrete ◽

Damage Detection ◽

Structural Damage ◽

Concrete Beams ◽

Element Model ◽

Reinforced Concrete Beams ◽

Strain Mode ◽

Finite Element Software ◽

Injury Models

This paper describes the strain mode damage detection theory and a three-dimensional reinforced concrete beams finite element model was built by finite element software. The different degree injury models tests were compared. Experiment’s results show that the first four natural frequencies of different degree injury models are small differences while the corresponding strain modes have a significant changed in damage location. The structure of the strain mode changes are still evident when structural damage occurred in the strain mode node.

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