Development Length of GFRP Rebars in Reinforced Concrete Members under Flexure

Alvaro Ruiz Emparanza, Francisco De Caso, Antonio Nanni

Research output: Chapter or section in a book/report/conference proceedingChapter in a published conference proceeding


In reinforced concrete (RC) structures, a proper bond between the reinforcement and the concrete is key for an appropriate composite action. To-date limited studies exist that evaluate the bond of fiber reinforced polymer (FRP) bars in concrete members under flexure and its effect on the development length required to ensure a full stress transfer. In this paper, the bond strength developed by glass FRP (GFRP) and steel rebars is evaluated and compared by testing 16 RC beams under three-point-bending. The beams were 1.83 m long and had a section of 150 x 360 mm. Different embedment lengths were evaluated as a function of the bar diameter (db): 30 db, 40 db, and 50 db for GFRP reinforced specimens, and 20 db, and 30 db for steel reinforced beams. Two different GFRP rebar types (six beams for each) and conventional steel (four beams) were used as reinforcement; all the rebars had a nominal diameter of 12.7 mm. Based on the results presented herein, GFRP rebars have a lower bond capacity than steel rebars. Also, the development lengths as suggested by actual code provisions for GFRP rebars (ACI 440.1R-15) appear to be over-conservative: the theoretical development length values were around 110% - 188% higher than the experimental results for the tested GFRP rebars, while the predicted development length for steel rebars according to ACI 318 was about 83% higher than the experimental results.

Original languageEnglish
Title of host publicationDevelopment and Applications of FRP Reinforcements, DA-FRPR 2021
EditorsRadhouane Masmoudi
PublisherAmerican Concrete Institute
Number of pages11
ISBN (Electronic)9781641951951
Publication statusPublished - 21 Oct 2022
Externally publishedYes
EventDevelopment and Applications of FRP Reinforcements, DA-FRPR 2021 - ACI Virtual Concrete Convention 2021 - Virtual, Online, USA United States
Duration: 17 Oct 202121 Oct 2021

Publication series

NameAmerican Concrete Institute, ACI Special Publication
ISSN (Print)0193-2527


ConferenceDevelopment and Applications of FRP Reinforcements, DA-FRPR 2021 - ACI Virtual Concrete Convention 2021
Country/TerritoryUSA United States
CityVirtual, Online

Bibliographical note

Funding Information:
ACI member Alvaro Ruiz Emparanza, Ph.D. is the Director of Engineering and Business Development of Mafic USA, LLC. He graduated with a Ph.D. in Civil Engineering from the University of Miami. His research interests included the durability assessment of alternative reinforcing systems for concrete structures, such as, fiber reinforced polymer (FRP) rebars, and the structural performance of reinforced concrete structures reinforced with FRP. During his academic career, he has been awarded with multiple fellowship and scholarships, including the President’s Fellowship Award by the American Concrete Institute (ACI) Foundation. He is Chair of the committee S-805 and active member of various committees: Development, SYPAC, S-806, 440, 440-H, and 440-K. Prior to pursuing his PhD, he did his bachelor’s in civil engineering at the University of the Basque Country (San Sebastian, Spain) and his masters, also in civil engineering, at the University of Applied Science Fachhochshule Muenster (Muenster, Germany). He graduated with honors from both programs.


  • bond
  • composites
  • development length
  • flexure
  • GFRP
  • sustainability

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science


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