Crack Width Prediction for Concrete Beams Strengthened with Carbon FRP Composites

Al-Saawani, Mohammed A.; El-Sayed, Ahmed K.; Al‐Negheimish, Abdulaziz I.

doi:10.1061/(asce)cc.1943-5614.0000805

Cited by 11 publications

(6 citation statements)

References 12 publications

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“…Polymers 2021, 13,3322 3 of 25 at a plate end and propagates along the interface of concrete substrate and FRP without reaching the level of tension steel, as shown in Figure 1b. CDC debonding takes place due to the formation of major shear crack that extends to the bottom of the beam intersecting the FRP plate near its end.…”

Section: Pe Debonding Failurementioning

confidence: 99%

“…Polymers 2021, 13,3322 4 of 25 study increase the background knowledge on the PE debonding failure and help validate or improve the relevant design provisions currently in effect.…”

Section: Test Beamsmentioning

confidence: 99%

“…There are two main debonding failure modes: intermediate crack (IC)-induced debonding and plate end (PE) debonding. IC debonding occurs in FRP-strengthened RC beams in the region of high moment due to the opening of flexural cracks [6][7][8][9][10][11][12][13]. On the other hand, PE debonding initiates at the plate end region due to high interfacial and normal stresses [14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…Figure13. Comparisons of experimental versus predicted values for shear-based models: (a) El-Sayed et al[14]; (b) Al-Ghrery et al[15]; (c) fib Bulletin 90[38]; (d) ACI 440.2R[39]; (e) AS 5100.8[40]; (f) Concrete Society[41]; (g) Teng and Yao[21]; (h) Colotti et al[37]; (i) Smith and Teng[19]; (j) Ahmed and Van Germert[36]; (k) Jansze[35]; (l) Oehler[34].…”

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confidence: 99%

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Effect of Stirrups on Plate End Debonding in Reinforced Concrete Beams Strengthened with Fiber Reinforced Polymers

Al‐Negheimish¹,

El-Sayed²,

Al-Saawani³

et al. 2021

Polymers

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Plate end (PE) debonding is one of the critical debonding failure modes that may occur in reinforced concrete (RC) beams strengthened with externally bonded fiber reinforced polymers (FRPs). This study investigated the effect of internal steel stirrups on the PE debonding failure load of FRP-strengthened RC beams. The dimensions of the beams were 3400 × 400 × 200 mm. The beams were strengthened with carbon FRP (CFRP) sheets bonded to the soffit of the beams. The beams were divided into two series based on the distance of the cutoff point of the CFRP sheets from the nearest support. This distance was 50 mm or 300 mm, and the amount of steel stirrups was varied in terms of varying the stirrup diameter and spacing. The beams were simply supported and tested under four-point bending. The test results indicate that the effect of stirrups on the load carrying capacity of the beams was more pronounced for the beams with CFRP sheets extended close to the supports. It was also indicated that beams with larger amounts of stirrups failed in PE debonding by concrete cover separation while beams with lower amounts of stirrups failed in PE by either PE interfacial debonding or critical diagonal crack-induced debonding. The beams were analyzed using several analytical models from design guidelines and the literature. The result of analysis indicates that most of the available models failed to reflect the effect of stirrups in predicting PE debonding failure load of the beams. On the other hand, the models of El-Sayed et al. and Teng and Yao were able to capture such an effect with the best predictions provided by El-Sayed et al. model.

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Section: Pe Debonding Failurementioning

confidence: 99%

“…Polymers 2021, 13,3322 4 of 25 study increase the background knowledge on the PE debonding failure and help validate or improve the relevant design provisions currently in effect.…”

Section: Test Beamsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of Stirrups on Plate End Debonding in Reinforced Concrete Beams Strengthened with Fiber Reinforced Polymers

Al‐Negheimish¹,

El-Sayed²,

Al-Saawani³

et al. 2021

Polymers

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“…This is attributed to the excellent characteristics of FRP materials that include high tensile strength, lightweight, corrosion resistance, and ease of installation. Numerous research work has been conducted to investigate the flexural performance of RC beams strengthened with EB FRP composites [1][2][3][4][5][6][7]. These studies have led to increase in the knowledge of the structural behavior of FRP-strengthened RC beams.…”

Section: Introductionmentioning

confidence: 99%

Mitigation of Concrete Cover Separation in Concrete Beams Strengthened with Fiber-reinforced Polymer Composites

Al-Saawani

El-Sayed

Al‐Negheimish

2022

IOP Conf. Ser.: Earth Environ. Sci.

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Strengthening of reinforced concrete (RC) beams using fiber reinforced polymers (FRP) is an effective method that is gaining more acceptance worldwide. However, failure of the strengthened beams at the plate-end region by concrete cover separation (CCS) compromises the effectiveness of such a strengthening system. Among available anchorage systems to remedy such problem, the use of FRP U-wraps at the end region of the externally bonded FRP has the potential to prevent CCS failure. Most studies in the literature suffer from poor design of test specimens and the use of random amounts of FRP anchorage. This resulted in nonconclusive findings and contradicting results on the real effectiveness of FRP U-wraps as an anchorage to prevent plate-end debonding failure. That in turn has been reflected in the lack of reliable design methods for the design of FRP U-wrap anchorage. In this paper, the effect of FRP U-wraps on the mitigation of CCS failure in FRP-strengthened RC beams was experimentally examined and quantified. The study included full-scale RC beams strengthened in flexure using carbon FRP (CFRP) sheets and anchored at the plate-end region using vertical CFRP U-wraps. The test variable was the amount of CFRP U-wrap that is required to achieve complete mitigation of CCS. The test results indicated the effectiveness of FRP U-wraps on mitigating CCS failure once the required area of CFRP U-wrap was placed. Relevant design models were presented and assessed against the experimental results of the current study. The comparisons indicated inaccurate predictions for the area of FRP U-wrap that is required to prevent CCS. This sheds the light on the need for developing a more reliable and accurate method for the design of an end anchorage to prevent CCS failure.

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Cracking and failure mode behavior of hybrid FRP strengthened RC column members under flexural loading

Balla,

Prakash

2024

Structural Concrete

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Strengthening of reinforced concrete (RC) members in bridges and buildings is often required to improve flexural performance. Strengthening using fiber‐reinforced polymer (FRP) composites has become popular as FRPs offer multiple advantages compared with conventional strengthening practices like steel jacketing and concrete enlargement. External bonding (EB) using carbon FRP (CFRP) laminates/fabric has become a common strengthening practice. The effectiveness of the EB strengthened system is reduced due to possible debonding of FRP from concrete substrate. The near‐surface mounting (NSM) of FRP laminates is efficient in reducing the debonding failure, but it is not effective under dominant compression loading. Hybrid FRP (HYB) strengthening combines the advantages of both the NSM and EB techniques. HYB strengthening can enhance the performance of RC members under all loading combinations. The main objective of this study is to understand the flexural crack opening behavior of control and hybrid FRP strengthened RC column members under pure bending. The digital image correlation (DIC) analysis shows that the crack width and its propagation are significantly reduced due to hybrid FRP strengthening. The crack widths measured using the DIC are compared with the analytical predictions based on Eurocode 2 and fib bulletin 90. HYB FRP strengthening increased the strength and post‐cracking stiffness of RC elements under flexure without compromising the ductility. In addition, the HYB strengthening distributed the damage under flexural loading, unlike localized damage observed in control RC elements.

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Crack Width Prediction for Concrete Beams Strengthened with Carbon FRP Composites

Cited by 11 publications

References 12 publications

Effect of Stirrups on Plate End Debonding in Reinforced Concrete Beams Strengthened with Fiber Reinforced Polymers

Effect of Stirrups on Plate End Debonding in Reinforced Concrete Beams Strengthened with Fiber Reinforced Polymers

Mitigation of Concrete Cover Separation in Concrete Beams Strengthened with Fiber-reinforced Polymer Composites

Cracking and failure mode behavior of hybrid FRP strengthened RC column members under flexural loading

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