Size effect in uncracked and pre-cracked reinforced concrete beams shear-strengthened with composite jackets

Nguyen-Minh, Long; Rovňák, Marián

doi:10.1016/j.compositesb.2015.02.035

Cited by 30 publications

(17 citation statements)

References 24 publications

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“…Coating the carbon fiber sheet with CNT enriched sizing agent enhances the adhesion between the fibers and epoxy resin, but prevents the resin to immerse inside the fiber sheet, hence reduce the amount of fibers that participate in carrying the load. 4. SEM micrographs showed that more matrix debris and concrete fragments are attached to the carbon fiber in the case of using CNT modified epoxy (B-CNT specimens) compared to B-NE specimen.…”

Section: Discussionmentioning

confidence: 97%

Effect of carbon nanotubes on strengthening of RC beams retrofitted with carbon fiber/epoxy composites

2016

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Section: Discussionmentioning

confidence: 97%

Effect of carbon nanotubes on strengthening of RC beams retrofitted with carbon fiber/epoxy composites

2016

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“…Nguyen-Minh and Rovnak [25] examined the shear response of original (uncracked) or precracked RC beams that have been strengthened or repaired, respectively, using U-shaped jackets made of epoxy-bonded glass or carbon FRP sheets. Test results indicated that the initial damage influenced the overall response of the jacketed beams.…”

Section: Jacketing As a Repair Technique In Damaged Rc Structural Memmentioning

confidence: 99%

“…The aforementioned literature review reveals that the majority of the conducted research is focused on the application of nonconventional jackets in strengthening methods of original RC structural members [17][18][19]21,22,24,[26][27][28][30][31][32][33][34]36,[38][39][40][41][42][43][44][45][48][49][50]56]. Significantly fewer studies investigate such jackets for the repair of preloaded and slightly damaged RC specimens [20,23,25,29,35,37,46,47,[51][52][53][54][55]. Further, very few studies (only five from 40) examine the jacketing retrofit of heavily damaged beams failed in shear [25,29,[52][53][54].…”

Section: Research Significancementioning

confidence: 99%

“…These reasons have led researchers to switch to new jacketing techniques with alternative materials such as steel [17][18][19], advanced materials such as fiber reinforced polymer (FRP) [20][21][22][23][24][25], textile reinforced concrete or mortar [26][27][28][29] and shape memory alloys [30][31][32], cement-based materials such as ferrocement [33][34][35][36], steel fibrous concrete or mortar [37][38][39][40], high-performance fiber reinforced concrete [41][42][43][44][45][46][47][48], self-compacting concrete (SCC) [49][50][51][52][53][54], and thin slightly reinforced flowable mortar [55,56]. Many of these jacketing techniques have been proved successful substitutes to common RC jacketing.…”

Section: Introductionmentioning

confidence: 99%

“…Many of these jacketing techniques have been proved successful substitutes to common RC jacketing. However, most of these studies investigate jackets as strengthening technique applied to undamaged RC members and only some of them [20,23,25,29,35,37,46,47,[51][52][53][54][55] examine jacketing as a method to repair already damaged RC members, as stated and discussed below.…”

Section: Introductionmentioning

confidence: 99%

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Repair of Heavily Damaged RC Beams Failing in Shear Using U-Shaped Mortar Jackets

et al. 2019

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The effectiveness of slightly reinforced thin U-shaped cementitious mortar jacketing for the repair of damaged shear-critical reinforced concrete beams is experimentally investigated. The test project includes two parts. In the first one, five concrete beams over-reinforced against flexure and under-reinforced against shear with different ratio of closed stirrups were initially subjected to monotonic loading until failure. The initially tested beams have been designed to fail in shear after wide diagonal cracking and to exhibit various strength and deformation capacities along with different levels of damages. In the second experimental part, the heavily damaged beams were jacketed with mild steel small diameter U-shaped transverse stirrups and longitudinal reinforcing bars. The retrofitted specimens using the proposed jacketing technique were tested again following the same four-point-bending load scheme. Based on the overall performance of the beams, it is deduced that the shear strength and deformation capability of the jacketed beams were substantially increased compared to the corresponding capacities of the initial beams. Further, although all beams failed in a shear abrupt manner, the retrofitted ones exhibited reduced brittleness and higher deflections at failure up to six times with respect to the initially tested specimens. The level of the initial damage influences the efficiency of the jacketing. Additional test data derived from relative shear-damaged beam specimens and retrofitted with similar thin jackets is also presented herein in order to establish the effectiveness of this repair system and to clarify the parameters affecting its structural reliability. Comparisons indicated that jacketed beams can alter the failure mode from brittle shear to ductile flexural under certain circumstances.

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Proposal and evaluation of new models for predicting the FRP contribution to shear strength in reinforced concrete beams using gene expression programming

Alacali,

Akkaya,

Sengun

et al. 2024

Neural Comput & Applic

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Fiber-reinforced polymers (FRP) have been widely used in shear strengthening applications of reinforced concrete (RC) beams. The accurate prediction of the FRP contribution to the shear strength of beams is essential for reliable design. Gene expression programming (GEP) has been widely utilized because it reliably expresses complex relationships between experimental variables. In this study, three new GEP models are proposed for three different strengthening configurations of FRP such as fully-wrapping, U wrapping, and side-bonding to predict the FRP contribution to shear strength. These models are developed using the most comprehensive database containing a total of 811 strengthened beams (350 fully-wrapped, 328 U-wrapped, and 133 side-bonded. Many variables have been considered in the proposed GEP models, including those that have been experimentally effective but are often neglected in existing literature equations, such as the shear span-to-effective depth ratio $$(a/d)$$ ( a / d ) and the stirrup ratio ($${\rho }_{w}$$ ρ w ). Additionally, the reliability of existing equations in the literature and the proposed GEP models for predicting the FRP contribution to shear strength was statistically evaluated. As a result of this evaluation, the proposed GEP models for each strengthening configuration of FRP yielded the most accurate statistical results, with the lowest coefficient of variation (COV), and the highest coefficient of correlation (R).

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Size effect in uncracked and pre-cracked reinforced concrete beams shear-strengthened with composite jackets

Cited by 30 publications

References 24 publications

Effect of carbon nanotubes on strengthening of RC beams retrofitted with carbon fiber/epoxy composites

Effect of carbon nanotubes on strengthening of RC beams retrofitted with carbon fiber/epoxy composites

Repair of Heavily Damaged RC Beams Failing in Shear Using U-Shaped Mortar Jackets

Proposal and evaluation of new models for predicting the FRP contribution to shear strength in reinforced concrete beams using gene expression programming

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