Reference-free determination of debonding length in reinforced concrete beams using guided wave propagation

2019 ◽  
Vol 207 ◽  
pp. 291-303 ◽  
Author(s):  
Beata Zima ◽  
Rafał Kędra
Keyword(s):  
Wave Propagation ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Guided Wave ◽  
Reinforced Concrete Beams ◽  
Guided Wave Propagation

scholarly journals Influence of the percentage of reinforcement by unstressed rebar on the deformability of pre-stressed RC beams

2021 ◽  
Vol 27 (3) ◽  
pp. 212-216
Author(s):  
Yaroslav Blikharskyy ◽  
Jacek Selejdak ◽  
Taras Bobalo ◽  
Roman Khmil ◽  
Mykhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Practical Significance ◽  
Pure Bending ◽  
Static Loads ◽  
Steel Bars ◽  
Periodic Profile

Abstract This article presents the materials of deformability studies of pre-stressed steel-concrete beams reinforced with a package of reinforcement with different ratio of tape and rebar in the pure bending moment zone. The aim of the research was determination of the reinforcement percentage influence, for pre-stressed reinforced concrete beams reinforced with a package of reinforcement on their deformability. Also, the aim was to evaluate the effectiveness of using pre-stressed rebar in combined reinforcement. The practical significance of the experimental research is to study the deformability in pre-stressed bending elements with external tape and rebar reinforcement, taking into account the influence of different ratios of reinforcement areas within the combined reinforcement and development of proposals for such structures` calculation and design. The scientific novelty of the research is in obtaining the deformability characteristics of reinforced concrete beams reinforced with a package of reinforcement (tape and steel bars with periodic profile) with different ratios in the case of static loads` action.

scholarly journals Calculation of steel-reinforced concrete beam for instant loading taking into account the non-linearity of the concrete diagram ε-σ

2020 ◽  
Vol 17 (2) ◽  
pp. 85-94
Author(s):  
S. O. Chepilko ◽  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
System Of Equations ◽  
Nonlinear System Of Equations ◽  
Steel Reinforced Concrete

Issues of calculating steel-reinforced concrete beams are considered taking into account a nonlinear concrete diagram based on the Sargin formula. The nonlinear system of equations for determination of curvature and neutral axis, which is solved numerically, is written in explicit form. Explicit expressions for determination of other calculated quantities needed for design of steel-reinforced concrete beams are derived. Numerical examples are given. The analysis of accounting nonlinearity in comparison with the linear calculation is carried out.

Damage Assessment of Reinforced Concrete Beams by Complex Ratios of Transfer Functions

2006 ◽  
Vol 321-323 ◽  
pp. 357-362 ◽  
Author(s):  
Chih Peng Yu ◽  
Chia Chi Cheng ◽  
Chih Hung Chiang
Keyword(s):  
Reinforced Concrete ◽  
Transfer Functions ◽  
Concrete Beams ◽  
Field Tests ◽  
High Sensitivity ◽  
Reinforced Concrete Beams ◽  
Numerical Studies ◽  
Complex Ratio ◽  
Local Defects

In this paper, a newly developed approach for the determination of characteristics associated with local defects of a beam is briefly introduced. From the numerical studies carried out in this study, the complex ratio between two transfer functions associated with an imaginary intact beam and a damaged beam can provide such information. Based on the numerical studies, the rules in determining degree of damages and locations of defects were first briefly outlined. These idealized rules were then verified by experimental data obtained from dynamic tests of realistic specimens of simply-supported reinforced concrete beams. The preliminary results indicate that the defined ratio of transfer functions can potentially serve as an exaggerated indication for the degree of changes in certain modal responses. Thus, the proposed ratio of transfer functions can be used to assist system identification, while the nature of high sensitivity also restricts its direct application to certain complicated data associated with field tests. A variety of test setup for both receivers and impact sources were studied and the test results appear to agree with designated conditions of the specimens.

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.

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