Fracture monitoring of steel and GFRP reinforced concrete beams using acoustic emission and digital image correlation techniques
About: This article is published in Structural Concrete.The article was published on 2021-02-23. It has received 6 citations till now. The article focuses on the topics: Digital image correlation & Acoustic emission.
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18 Apr 2022
TL;DR: In this article , the authors investigated non-destructive testing (NDT) methods applicable to inspection of in-service FRP reinforced/strengthened concrete (FRP-RSC) bridge elements.
Abstract: The use of fiber reinforced polymer (FRP) materials has been on the rise in bridge construction industry. They have been mostly utilized for strengthening purposes, especially as externally bonded reinforcement for columns, slabs, and beams. Their lightweight, flexibility and ease of installation, and higher strength offer an ideal solution for increasing the axial, bending, and shear resistance of existing concrete elements, as well as restoration and retrofitting of damaged members. FRP bars have also been used as internal reinforcement for concrete structural elements, providing corrosion-resistant alternatives to conventional steel reinforcements. Although the application of FRP for concrete members has offered many advantages, there have been issues and concerns associated with their long-term performance including their debonding from a concrete surface or within a concrete element. Accordingly, despite their durability, concrete elements strengthened/reinforced with FRP materials need to be inspected periodically to detect potential issues and hence prevent any premature failures. This study investigates Non-Destructive Testing (NDT) methods applicable to inspection of in-service FRP reinforced/strengthened concrete (FRP-RSC) bridge elements. Accordingly, this study first introduces damages and anomalies attributed to FRP reinforced/strengthened concrete bridge elements, and causes are discussed. The study includes a review of some promising NDT methods for the detection of these damages. The results of this study are expected to provide the inspection community more clarity in the application of NDT to FRP reinforced/strengthened concrete.
4 citations
TL;DR: In this article , an experimental study was conducted to assess the out-of-plane behavior (four-point flexural bending) and performance of EPS sandwiched concrete panels subjected to varying degrees of corrosion using impressed current corrosion technique.
3 citations
TL;DR: In this article , an image-based procedure is developed for post-earthquake residual stiffness quantification of reinforced concrete columns, based on the availability of the structural information, five closed-form regression-aided equations are offered for estimating the stiffness loss in seismically damaged RC columns using predicting parameters among fractal indices, concrete strength, and the aspect ratio of the column.
Abstract: The seismic damage to reinforced concrete (RC) components is conventionally quantified through various damage indices. In this paper, an image‐based procedure is developed for post‐earthquake residual stiffness quantification of RC columns. The proposed scenario‐based methodology is built upon the multifractal indices of the surface crack maps of the seismically damaged RC columns as the complexity measure for the images. An extensive databank from experiments on RC column specimens with a broad range of structural characteristics are collected and employed for generation and validation of the proposed procedure. Based on the availability of the structural information, five closed‐form regression‐aided equations are offered for estimating the stiffness loss in seismically damaged RC columns using predicting parameters among fractal indices, concrete strength, and the aspect ratio of the column. Results reveal that multifractal dimensions of crack maps are largely correlated with the stiffness degradation in RC columns. A sample specimen at various stiffness‐based damage indices is also presented as a case study to evaluate the predicted versus measured damage indices. The updated stiffness values acquired by the proposed equations can be utilized for stability evaluation, system identification, or further analysis of the seismically damaged RC buildings following an earthquake.
3 citations
TL;DR: In this paper , the authors investigated the load carrying behavior of concrete beams reinforced with conventional deformed steel bars and seven-bundled BFRP bars through four-point flexural test.
2 citations
TL;DR: In this paper , the ability of two commonly used non-destructive testing (NDT) methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements was investigated.
Abstract: Fiber-Reinforced Polymer (FRP) bars/strands are the most promising alternative to their steel counterparts for reinforcing concrete elements due to their resistance to corrosion, lighter weight, higher strength and better durability. However, very limited research has been conducted in relation to non-destructive testing (NDT) methods that are applicable to damage detection in FRP bars or the detection of FRP reinforcements embedded in concrete. The ability to assess the condition of the relatively new and unique FRP reinforcements will increase the confidence of the construction industry in their use as a reliable substitute for steel reinforcements. This paper investigates the ability of two of the most commonly used NDT methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements. GPR and PAU tests were performed on two slab specimens reinforced with GFRP (Glass-FRP) bars, the most commonly used FRP bar, with variations in their depth, size and configuration, and a slab specimen with different types of available FRP reinforcements. The results show that GPR devices can detect GFRP bars/strands and CFRP (Carbon-FRP) strands to some extent, and their detectability increases with the increase in their antenna center frequency. On the contrary, PAU is only capable of detecting GFRP and CFRP strands. The results of this paper also emphasize the need for further research and developments related to NDT applications to embedded FRP bars.
2 citations
References
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TL;DR: In this paper, the authors developed and limited experimental verification of a method which can determine displacements and gradients using the Newton-Raphson method of partial corrections, which was shown to be accurate in determining displacement and certain gradients, while using significantly less CPU time than the current coarse-fine search method.
Abstract: Digital image correlation is finding wider use in the field of mechanics. One area of weakness in the current technique is the lack of available displacement gradient terms. This technique, based on a coarse-fine search method, is capable of calculating the gradients. However the speed at which it does so has prevented widespread use. Presented in this paper is the development and limited experimental verification of a method which can determine displacements and gradients using the Newton-Raphson method of partial corrections. It will be shown that this method is accurate in determining displacements and certain gradients, while using significantly less CPU time than the current coarse-fine search method.
1,304 citations
TL;DR: Ncorr is an open-source subset-based 2D DIC package that amalgamates modern DIC algorithms proposed in the literature with additional enhancements and several applications of Ncorr that both validate it and showcase its capabilities are discussed.
Abstract: Digital Image Correlation (DIC) is an important and widely used non-contact technique for measuring material deformation. Considerable progress has been made in recent decades in both developing new experimental DIC techniques and in enhancing the performance of the relevant computational algorithms. Despite this progress, there is a distinct lack of a freely available, high-quality, flexible DIC software. This paper documents a new DIC software package Ncorr that is meant to fill that crucial gap. Ncorr is an open-source subset-based 2D DIC package that amalgamates modern DIC algorithms proposed in the literature with additional enhancements. Several applications of Ncorr that both validate it and showcase its capabilities are discussed.
1,184 citations
"Fracture monitoring of steel and GF..." refers background in this paper
...1.(43) It is important to note that DIC analysis was carried out on the selected zone marked as AOI in Figure 2....
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18 Apr 2005
TL;DR: The guide for the design and construction of concrete reinforced with FRP bars is published by the American Concrete Institute (ACI) as discussed by the authors, which has been used as the internal reinforcement in concrete members to replace conventional steel rebars.
Abstract: This paper reports on the key features of the “Guide for the Design and Construction of Concrete Reinforced with FRP Bars” issued by the American Concrete Institute (ACI). For new construction, FRP bars have been used as the internal reinforcement in concrete members to replace conventional steel rebars for a host of reasons. The principles for design and construction were first established and proposed to industry in 2001. The third revision of the guide is now under preparation.
702 citations
TL;DR: In this article, two crack classification methods are compared and discussed from results of three types of concrete failure tests, and it is shown that the ratios of the shear crack which are identified by Green's functions for moment tensor analysis are good agreement with those by parameter analysis in the case that the proportion of the RA value and the average frequency is set to 1-200.
666 citations
"Fracture monitoring of steel and GF..." refers background in this paper
...This section evaluates the crack propagation in terms of micro and macro cracking in SR and GR beams based on the resulting AE-signals during flexural testing.(45,46) Figures 4 and 5 present the plots of increase in cumulativeAE hits, a sudden rise in CSS-curve, and variation of the amplitude of AE hits with increasing flexural loading in SR and GR beams along with load-time curve giving an indication of the progression of fracture/cracking in the two types of beams from initiation of cracking to the ultimate failure of these beams....
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TL;DR: In this article, a state-of-the-art report is focused on corrosion inhibitors used in concrete and is based on published studies in the last decade, focusing on the most commonly used inhibitors such as amino alcohols (AMAs), calcium nitrites (CN), and sodium monofluorophosphates (MFPs).
431 citations