Debonding failure modes of flexural FRP-strengthened RC beams

Aram, Mohammad Reza; Czaderski, Christoph; Motavalli, Masoud

doi:10.1016/j.compositesb.2007.10.006

Cited by 140 publications

(59 citation statements)

References 18 publications

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“…Aram ve diğ. [14], lifli polimer plakalarla güçlendirilmiş betonarme kirişlerdeki farklı levha ayrılması şekillerini tanımlamış ve bunların engellenmesi için alınabilecek önlemleri belirlemişlerdir Geçmişte yapılmış olan araştırmalar, çelik levha ve karbon kumaşlarla yapılan güçlendirme işlemlerinin betonarme kirişlerin dayanım ve davranışına önemli katkıları bulunduğunu, ancak bu malzemelerin güçlendirmede tek başına kullanımının bazı dezavantajlar ortaya çıkardığını göstermiştir. Bu çalışmada iki malzemenin kompozit olarak beraber kullanılmasının betonarme kiriş davranışına yapacağı katkılar araştırılmıştır.…”

Section: Gi̇ri̇ş (Introduction)unclassified

Betonarme Kirişlerin Dıştan Yapıştırılmış Karbon Kumaş Ve Çelik Levhalardan Oluşan Kompozit Malzemeyle Güçlendirilmesi

Aykaç¹,

Açar²

2014

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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ÖZETBetonarme kirişlerin çekme yüzüne çelik levha veya lifli polimer (FRP) kumaş yapıştırılarak güçlendirmesi yaygın olarak kullanılan yöntemlerdendir. Bu malzemelerden FRP yüksek dayanım talebini karşılayabilmesine rağmen, süneklik talebini karşılamada genellikle yetersiz kalmaktadır. Çelik ise hem dayanım hem de süneklik talebini karşılayabilmektedir. Ancak özellikle dayanım talebinin yüksek olduğu durumlarda kalın levha kullanımının gerekmesi, bazı uygulama zorlukları doğurmaktadır. Bu çalışmada sünekliğin yanı sıra yüksek dayanım talebinin de gerekli olduğu durumlarda her iki malzemenin birbirinin eksiklerini tamamlayacak şekilde kullanılmasının betonarme kiriş davranışı üzerindeki etkileri araştırılmıştır. Bu amaçla, biri yalın, ikisi sadece karbon kumaşlarla, diğerleri ise hem karbon kumaş hem de çelik levhalarla güçlendirilmiş toplam 11 adet betonarme kiriş düşey yükler altında test edilmiştir. Çalışmada, karbon kumaş ve çelik levha katman sayısı ile yapıştırma sırası ve çelik levha kalınlığı parametre olarak ele alınmıştır. İki malzemenin beraber kullanımının, kirişlerin davranış ve dayanımı üzerine önemli katkılarda bulunduğu ve yapıştırma sırasının kiriş davranışını belirleyen en önemli değişken olduğu görülmüştür.Anahtar Kelimeler: Betonarme kiriş, güçlendirme, çelik levha, karbon kumaş, lifli polimer STRENGTHENING OF REINFORCED CONCRETE BEAMS WITH AN EXTERNALLY BONDED COMPOSITE MATERIAL COMPOSED OF FRP FABRIC AND STEEL PLATE ABSTRACTBonding steel plates or FRP laminates to the tension faces of reinforced concrete beams are among the common strengthening methods. Among these two strengthening materials, FRP generally is not capable of fulfilling the ductility demand while fulfilling the high strength demand. Mild steel, on the other hand, is capable of fulfilling both the strength and the ductility demands. However, the use of thick plates, whose application is impractical, might be needed in the case of high strength demand. In the present study, the effects of the composite use of the two materials to overcome the shortcomings of the individual use of each material on the behavior of reinforced concrete beams was investigated. For this purpose, a total of 11 reinforced concrete beams, including a plain beam, two reference beams strengthened with only FRP laminates and 8 beams strengthened with both steel plates and FRP laminates, were tested under transverse loading. The number of CFRP and steel layers, the bonding sequence of these layers and the plate thickness were adopted as the parameters of the present study. The composite use of CFRP and steel proved to have significant contributions to the behavior and strength of reinforced concrete beams and the bonding sequence of the layers was found to be the most important parameter influencing the beam behavior.

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Section: Gi̇ri̇ş (Introduction)unclassified

Betonarme Kirişlerin Dıştan Yapıştırılmış Karbon Kumaş Ve Çelik Levhalardan Oluşan Kompozit Malzemeyle Güçlendirilmesi

Aykaç¹,

Açar²

2014

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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“…And, beyond this point, stress will become constant and equal to yield stress ( Figure 10(c)). Table 3 presents the mechanical characteristics of the steel rebars used in the specimens [15,16,21,22].…”

Section: Validity Of the Proposed Approachmentioning

confidence: 99%

“…Figure 15 plots diagrams for interfacial shear stress along the plate during three cracking events, yielding point of tensile Figure 15. Shear stress variations along the line passing through the top surface of plate (the surface in contact with the concrete): (a) In the Federal's specimen [16], (b) in the Rahimi's specimen [15], (c) in the Wu's specimen [21], and (d) in Yao's specimen [22].…”

Section: Validity Of the Proposed Approachmentioning

confidence: 99%

“…These specimens were introduced by the Swiss Federal Lab in 1996 and reported in [16] Tables 1 to 4 and are presented in Figures 5 to 9. The non-linear behavior of concrete, such as cracking and con nement, has been accounted for using Lee and Fenves's theory which is available in the materials library of the software used [20].…”

Section: Validity Of the Proposed Approachmentioning

confidence: 99%

“…Hence, some studies have suggested debonding to occur with reduced sti ness in elements at the interfacial layers [12] (smeared crack model). Hu et al (2004) [14], Rahimi and Hutchinson (2001) [15], Aram et al (2005) [16], and Lu and Ayoub (2010) [17] also used a similar method. Other methods, such as extended nite element (XFEM) and moving mesh technique, are the combination of smeared and discrete crack methods.…”

Section: Introductionmentioning

confidence: 99%

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Simulating FRP Debonding From Concrete Surface in FRP Strengthened RC Beams: A Case Study

Mostofinejad

Hosseini

2017

Scientia Iranica

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Abstract. Reinforced Concrete (RC) beams strengthened with Fiber Reinforced Polymer (FRP) sheets may fail due to debonding failure. In such cases, the FRP sheet is detached from the RC beam before real damages are in icted on the beam. In this paper, a procedure is developed based on smeared cracks approach for simulating the debonding process in FRP strengthened RC beams within the framework of nite element. For this purpose, the challenges facing the simulation of debonding mechanism are initially studied, and a method is proposed in a second stage of combating these problems using the cohesive elements available in the ABAQUS software. The validity of the proposed method is then tested by modeling four beams from those reported in the literature and by comparing the results with the experimental ones. Given the acceptable agreement observed between the experimental and numerical simulation results, the method is claimed to be valid and practicable. In a later section of the present paper, the proposed method will be used to investigate the e ects of length and width of the strengthening sheet on beam's behavior and its failure mechanism. The results of the present study reveal that longer FRP sheets increase load carrying capacity and mid-span displacement of strengthened RC beams.

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Experimental and numerical investigation of damaged concrete beams strengthened with FRP composed of different fibres and resins

Rahai

Saberi

2011

Structural Design Tall Build

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SUMMARY Strengthening of structures to avoid further damages is inevitable in different conditions. In this paper, to evaluate the effect of fibre‐reinforced polymer (FRP) plates on damaged and non‐damaged members, an extensive experimental programme is reported. Several beam specimens were built. Some specimens were strengthened after loading condition. The damaged specimens strengthened by FRP plates containing two different resins (epoxy or polyester) were tested. Other beam specimens were strengthened by composite plates before loading. Moreover, a numerical modelling procedure was performed, and it showed good agreement with experimental results. Results showed improvements in flexural capacity of damaged beams strengthened by FRP laminates or plates compared with the non‐damaged ones. Copyright © 2009 John Wiley & Sons, Ltd.

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Debonding failure modes of flexural FRP-strengthened RC beams

Cited by 140 publications

References 18 publications

Betonarme Kirişlerin Dıştan Yapıştırılmış Karbon Kumaş Ve Çelik Levhalardan Oluşan Kompozit Malzemeyle Güçlendirilmesi

Betonarme Kirişlerin Dıştan Yapıştırılmış Karbon Kumaş Ve Çelik Levhalardan Oluşan Kompozit Malzemeyle Güçlendirilmesi

Simulating FRP Debonding From Concrete Surface in FRP Strengthened RC Beams: A Case Study

Experimental and numerical investigation of damaged concrete beams strengthened with FRP composed of different fibres and resins

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