Reinforced concrete beams strengthened in flexure with near-surface mounted (NSM) CFRP strips: Current status and research needs

S. S. Zhang, T. Yu, G. M. Chen

Research output: Journal article publicationReview articleAcademic researchpeer-review

76 Citations (Scopus)


The near-surface mounted (NSM) FRP strengthening technique has attracted worldwide attention as an effective alternative to the externally bonded (EB) FRP strengthening technique. In the NSM FRP strengthening method, grooves are first cut in the concrete cover of a concrete member for the FRP reinforcement to be inserted and embedded using an adhesive. The NSM FRP method has many advantages over the EB FRP method, including a higher bonding efficiency and a better protection of the FRP reinforcement. Existing experimental studies have shown that FRP strips owned a better bond efficiency compared with other section shapes (e.g. round bars and square bars), due to the fact that they had a larger perimeter-to-cross-sectional area ratio. This paper presents a state-of-the-art review, particularly on the flexural strengthening of RC beams with NSM CFRP strips. The observed failure modes in laboratory experiments of such FRP-strengthened RC beams are classified and the existing strength models are examined along with the failure mechanisms behind. The main knowledge gaps to be bridged in future studies are also identified. This review partially formed the basis of the development of design provisions on the NSM strengthening technique in the relevant Hong Kong design guideline.

Original languageEnglish
Pages (from-to)30-42
Number of pages13
JournalComposites Part B: Engineering
Publication statusPublished - 15 Dec 2017
Externally publishedYes


  • FRP
  • Near-surface mounted (NSM)
  • RC beams
  • Strip

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

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