Reinforced Concrete Corbel Strengthened Using Carbon Fiber Reinforced Polymer (CFRP) Sheets

Souza, Rafael Alves de; Trautwein, Leandro Mouta; Ferreira, Maurício de Pina

doi:10.3390/jcs3010026

Cited by 7 publications

(4 citation statements)

References 9 publications

(15 reference statements)

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“…An innovation of the nineties of the past century was externally bonded fiber composite systems [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ]. They consist of fibers embedded into either organic matrix (Fiber-Reinforced Polymers—FRP) or inorganic matrix (Fiber-Reinforced Cementitious Matrix—FRCM).…”

Section: Shear Strengthening Of Existing Rc Beamsmentioning

confidence: 99%

Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads Using Externally Bonded Fiber Composite Materials

Foraboschi

2022

Materials

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Renovation, restoration, remodeling, refurbishment, and the retrofitting of buildings often imply applying forces (i.e., concentrated loads) to beams that before were subjected to distributed loads only. In the case of reinforced concrete structures, the new condition causes a beam to bear a concentrated load with the crack pattern that resulted from the distributed loads which had acted before. If the concentrated load is applied at or near the beam’s midspan, the new shear demand reaches the maximum where cracks are vertical or quasi-vertical, and where inclined bars are not common according to any standards. So, the actual shear capacity can be substantially lower than new shear demand due to the concentrated load. This paper focuses on reinforced concrete beams whose load distribution has to be changed from distributed to concentrated and presents a design method to bring the beam’s shear capacity up to the new demand. The method consists of applying fiber composites (fiber-reinforced polymers or fiber-reinforced cementitious material) with fibers at an angle of 45° bonded to the beam’s web. This kind of external reinforcement arrangement has to comply with some practical measures, which are presented as well. The paper also provides the analytical model that predicts the concentrated load-carrying capacity of a beam in the strengthened state. The model accounts for the crack’s verticality, which nullifies the contributions of steel stirrups, aggregate interlock, and dowel action, and for the effective bond length of each fiber, which depends on the distance between the ends of the fiber and the crack it crosses.

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Section: Shear Strengthening Of Existing Rc Beamsmentioning

confidence: 99%

Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads Using Externally Bonded Fiber Composite Materials

Foraboschi

2022

Materials

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“…It has also been shown that the strengthening achieved by unidirectional full wrapping horizontal CFRP sheets was considered the best configuration compared with that of inclined CFRP fabrics (45°). Souza et al [17] suggested a strengthening technique that included a localised repair using carbon fibre reinforced polymer (CFRP) sheets. The suggested technique allowed the concrete zone that was at risk of spalling to be contained with an acceptable level of safety.…”

Section: Externally Bonded Strengthening Of Rc Corbelsmentioning

confidence: 99%

Behaviour of reinforced concrete corbels strengthened by FRP composites and steel bars: a critical review

Al-Kaabi,

Al-Thairy,

Dhaheer

2023

IOP Conf. Ser.: Earth Environ. Sci.

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In reinforced concrete (RC) structures, corbels that extend from the faces of reinforced concrete columns are commonly employed to support primary beams and girders. Frequently, the use of corbels is limited to cantilevers with a shear span-depth ratio that is often less than 2. Because of this relatively low ratio, corbel strength is normally dominated by shear, which is comparable to deep beams. However, owing to some reasons (e.g., design and/or construction faults, modification of facility use, deterioration, and aging), strengthening of existing corbels is becoming of prime importance. The aim of the present paper is to conduct a critical review of commonly proposed techniques that have been implemented to strengthen RC corbels. These techniques comprised near surface mounted (NSM) steel bars, NSM fibre reinforced polymer (FRP) bars, and FRP sheets. The latter strategy included carbon (CFRP) and glass (GFRP) sheets. Hybrid strengthening (combining FRP sheets and FRP/steel bars) was also highlighted in this paper. The strengthened (upgraded) RC corbels were evaluated considering several parameters, including shear span to depth ratio (a/d), quantity and configuration of reinforcement, FRP type, and levels of damage in the tested specimens.

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“…Over the years many solutions have been proposed for the upgrading and repair of existing structures, spanning from the most traditional techniques and materials to the most modern and innovative ones, making use of composite materials, which are increasingly adopted not only for masonry structures, but also for reinforced concrete structures [38,39], even including some unconventional coupling [40,41].…”

Section: Introductionmentioning

confidence: 99%

New Frontiers of Composites Applications in Heritage Buildings: Repair of Exposed Masonry of St. Nicola Church in Pisa

Croce

2021

J. Compos. Sci.

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The upgrading and repair of masonry structures, which constitute a great part of built heritage, involve intricate aspects, in fact, the choice of the most suitable intervention technique is strongly dependent on its compatibility with superior preservation requirements. At present, beside more traditional approaches, many composite-based techniques are available, but, there are cases, such as exposed masonry, which are much more complicated to treat, since, to safeguard the original aspect, any intervention on the surface is precluded. In this paper, an innovative repair technique is discussed. The proposed method, highly adaptable and suitable for general application, is based on the insertion of a composite fabric into the mortar joints of the exposed masonry, partly relying on the indent repair technique traditionally used for the repair of masonry structures. Due to the peculiarities of the approach, the feasibility and efficiency of the solution cannot be demonstrated through application in the testing laboratory or on reduced samples, it was, therefore, necessary to identify a relevant case study for a field testing. After careful evaluation, duly considering the risks from the esthetic point of view, the proposed solution was implemented to repair the exposed masonry of the main façade and of the rear façade of the medieval San Nicola Church in Pisa, which is an outstanding example of the Pisan-Romanesque style. Thanks to a careful definition of the operational phases and to skilled workmanship, the solution was easily implemented in the year 2005, fully safeguarding the aesthetics of the façades, so demonstrating its feasibility. However, this successful outcome was only a first proof of the validity of the experiment, which also needed, for complete validation, the assessment of its efficiency over time. Only recently, after more than 15 years, it has been possible to ascertain that the intervention is still effective, because the crack patterns are stabilized and no reopening of the crack has occurred in the meantime, so achieving full confirmation.

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Reinforced Concrete Corbel Strengthened Using Carbon Fiber Reinforced Polymer (CFRP) Sheets

Cited by 7 publications

References 9 publications

Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads Using Externally Bonded Fiber Composite Materials

Strengthening of Reinforced Concrete Beams Subjected to Concentrated Loads Using Externally Bonded Fiber Composite Materials

Behaviour of reinforced concrete corbels strengthened by FRP composites and steel bars: a critical review

New Frontiers of Composites Applications in Heritage Buildings: Repair of Exposed Masonry of St. Nicola Church in Pisa

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