Strain monitoring of RC members strengthened with smart NSM FRP bars

Wang, Bo; Teng, Jinguang; Lorenzis, Laura De; Zhou, Limin; Ou, Jinping; Jin, Wei; Lau, Kin Tak

doi:10.1016/j.conbuildmat.2008.07.027

Cited by 38 publications

(20 citation statements)

References 31 publications

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“…Taking into account that those values depend on the discrete values of Lb that were tested, a global threshold of 100 mm can be defined. For both CFRP rectangular bars [3] and GFRP round bars [35] this limit is suggested to be equal to 200 mm.…”

Section: Bonded Lengthmentioning

confidence: 99%

“…force, F f,max [kN] Experimental pullout force, F f,max [kN] A1: L per,f (35) A2: L per,g (35) force, F f,max [kN] Experimental pullout force, F f,max [kN] A1: L per,f (137) A2: L per,g (137) Results for the analyses with SA standard (BPT database): (a) all specimens; (b) rectangular specimens only; (c) round specimens only. force, F f,max [kN] Experimental pullout force, F f,max [kN] A1: L per,f (35)A2: L per,g(35)…”

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confidence: 99%

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A review on the bond behavior of FRP NSM systems in concrete

Coelho

Sena-Cruz

Neves

2015

Construction and Building Materials

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This paper presents a review of current knowledge on the bond behavior of fiber reinforced polymer (FRP) systems inserted in the cover of concrete elements, commonly known as the near-surface mounted technique (NSM). In the first part, by studying the physics of the phenomenon, the typical failure modes, the most common bond tests and two of the most important design guidelines for FRP NSM systems are introduced. In the second part, a database of bond tests composed by 431 records is presented and the accuracy of existing design guidelines is assessed with this data. Lastly, the formulations proposed by these design guidelines are recalibrated based on the experimental results in the database.Keywords: FRP; NSM; Bond; Review grooves have vertical and parallel sides, square and rectangular bars explore better this grooves' geometry since a more uniform adhesive thickness is achieved. Moreover, with the use of round bars, split of the groove filling cover may occur due to the existing stresses perpendicular to the FRP. In the case of square and rectangular bars this normal stress component acts mainly towards the groove lateral concrete.Comparing square and rectangular bars, the latter maximize the ratio of surface to cross-section area, minimizing the bond stresses for the same tensile force in the FRP. Other advantage of using 3 rectangular bars is related with the simplicity of opening the grooves: a single saw cut is normally enough for obtaining the groove while with round/square bars two saw cuts and removal of the concrete in between are usually required. The main disadvantage of rectangular bars is the need for a deeper groove to provide the same reinforcement area.In terms of the adhesives used to bond FRP bars to concrete, epoxy adhesives are the most common, even though some researchers have used cement mortar [4,5]. In general, cement based adhesives have lower mechanical strength and higher curing time. On the other hand, they present better performance when subjected to high temperatures.The most recent comprehensive review on the NSM technique was published in 2007 [6]. In order to provide a wider overview of the technique, it was not focused on the bond. Moreover, since then, a manifold of experimental works focusing on bond performance of FRP NSM systems have been developed. Hence, the scope of this work is to provide a review on the bond behavior of FRP NSM systems in concrete. This review includes, in the first part, an introduction to the typical observed failure modes, the most commonly used bond tests and two of the most important design guidelines. In the second part of this paper, a database of 431 bond tests is presented, the accuracy of the design guidelines is tested and several modifications to these guidelines' formulations are proposed. FRP NSM technique Failure modes at structural levelConsidering a reinforced concrete element strengthened in bending (and/or shear) with a FRP NSM system, six failure modes combining different stress states on the three intervening materials (concrete, ...

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Section: Bonded Lengthmentioning

confidence: 99%

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confidence: 99%

A review on the bond behavior of FRP NSM systems in concrete

Coelho

Sena-Cruz

Neves

2015

Construction and Building Materials

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“…This produces an underestimation of the expected displacements. In order to take into account the different behaviour in constitutive law as well as in bonding to concrete of the composite bars, the formulae have to be modified, introducing some appropriate coefficients, which need to be experimentally validated [11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Flexural Behaviour of Concrete Beams Reinforced With GFRP Bars

Ascione

Mancusi

Spadea

2010

Strain

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The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Salerno University. The static behaviour under service conditions of concrete beams reinforced with GFRP (Glass Fibre‐Reinforced Polymer) as well as CFRP (Carbon Fibre‐Reinforced Polymer) bars and stirrups is examined. Within the whole experimental program concerning forty beams, two different concrete strengths and two different percentages of reinforcement are taken into consideration. The final aim is to investigate both deflections at midspan and crack widths. Moreover, the ultimate behaviour up to failure is also investigated. A part of this experimental program, concerning ten prototypes reinforced with GFRP bars, is here presented and discussed. Finally, comparisons with analytical predictions given by CNR‐DT 203/2006 are also shown.

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“…Because, at the time of concrete cracking, the possibility of the detachment of strain gauges from the structure is high. The epoxy-based-two component adhesives ensure good adhesion of strain gauges to the concrete surface [20,21].…”

Section: Selection and Installation Of Strain Gaugesmentioning

confidence: 99%

Health Monitoring of Nuclear Structure Containment Using Strain Gauges to Assess the Integrity

Parande

Kennedy

Muthusamy

et al. 2013

ISRN Construction Engineering

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Assessment of concrete structures and prediction of their health and life could be possible by online monitoring of the stress/strain level and is an intelligent tool to prevent accidents. Measuring strain pattern on structures is vital to evaluate the health of forced members. The present paper describes the methodology, instrumentation line up, and coding for LabVIEW software for continuous online strain data acquisition of structures for nuclear structures. The performance of strain gauges on concrete and steel containment structures of nuclear reactor and to assess the integrity and health of the containment structure is emphases in this research paper.

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Strain monitoring of RC members strengthened with smart NSM FRP bars

Cited by 38 publications

References 31 publications

A review on the bond behavior of FRP NSM systems in concrete

A review on the bond behavior of FRP NSM systems in concrete

Flexural Behaviour of Concrete Beams Reinforced With GFRP Bars

Health Monitoring of Nuclear Structure Containment Using Strain Gauges to Assess the Integrity

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