Process of debonding in RC beams shear-strengthened with FRP U-strips or side strips

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:49

Article

Chen, G. M.^1,2  Teng, J. G.¹  Chen, J. F.³ 

[1] Hong Kong Polytech Univ, Dept Civil & Struct Engn, Hong Kong, Hong Kong, Peoples R China

[2] Guangdong Univ Technol, Fac Civil & Transportat Engn, Guangzhou, Guangdong, Peoples R China

[3] Univ Edinburgh, Sch Engn, Inst Infrastruct & Environm, Edinburgh, Midlothian, Scotland

关键词: Fiber reinforced polymers (FRP);    Reinforced concrete beams;    Strengthening;    Shear failure;    Shear resistance;    Debonding;    Stress distribution;    Interfacial stress;   

DOI  :  10.1016/j.ijsolstr.2012.02.007

来源: Elsevier

【 摘 要 】

Reinforced concrete (RC) beams may be strengthened for shear using externally bonded fiber reinforced polymer (FRP) composites in the form of side bonding. U-jacketing or complete wrapping. The shear failure of almost all RC beams shear-strengthened with side bonded FRP and the majority of those strengthened with FRP U-jackets, is due to debonding of the FRP. The bond behavior between the externally-bonded FRP reinforcement (referred to as FRP strips for simplicity) and the concrete substrate therefore plays a crucial role in the failure process of these beams. Despite extensive research in the past decade, there is still a lack of understanding of how debonding of FRP strips in such a beam propagates and how the debonding process affects its shear behavior. This paper presents an analytical study on the progressive debonding of FRP strips in such strengthened beams. The complete debonding process is modeled and the contribution of the FRP strips to the shear capacity of the beam is quantified. The validity of the analytical solution is verified by comparing its predictions with numerical results from a finite element analysis. This analytical treatment represents a significant step forward in understanding how interaction between FRP strips, steel stirrups and concrete affects the shear resistance of RC beams shear-strengthened with FRP strips. (C) 2012 Elsevier Ltd. All rights reserved.

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