Materials and Structures

, Volume 48, Issue 1–2, pp 35–51 | Cite as

Effectiveness of strengthening by CFRP on behavior of reinforced concrete columns with respect to the buckling instability

  • Y. Si Youcef
  • S. AmzianeEmail author
  • M. Chemrouk
Original Article


The use of composite materials in the field of construction, such as, materials fully incorporated in the design, or as a means of strengthening after realization do not cease growing, particularly in reinforced concrete structures. Nevertheless, the result of the association between the strengthened reinforced concrete structure and the strengthening itself is not fully known. Our contribution in this field is an experimental research work, which consisted in studying the strengthening contribution on reinforced concrete columns in the objective to reduce the geometric instability caused by the slenderness effect. In the present case, the strengthening act consists of gluing a carbon fiber fabric around the columns using an epoxy adhesive. The required effect depends on the fibers orientation, for this purpose, three columns with various fibers arrangements were considered in addition to the control one (un-strengthened column). The four columns studied, have a square section and slenderness λ = 100, tested under a doubly eccentric compressive load. The results obtained are illustrated by: load–displacement, bending moment–curvature and bending moment-axial force responses. The obtained results indicate that strengthening using carbon fiber composites has a positive effect on the general behavior of reinforced concrete columns. Also, it shows that the CFRP envelope is efficient in improving the stability of strengthened columns with variable degrees according to the orientation of these fibers.


RC column Buckling Strengthening CFRP Geometrical slenderness 

List of symbols




Ultimate curvature


Elasticity modulus of the composite


Water on cement ratio


Flexional stiffness


Eccentricity of load


Radius of the column angles rounded

\(f_{\text{cC}}^{ '}\)

Confined concrete compressive strength

\(f_{\text{c0}}^{ '}\)

Unconfined concrete compressive strength


Yield stress of steels


Length-to-section depth ratio of the column


Bending moment peak


Ultimate bending moment


Axial peak load


Ultimate axial load


CFRP layer number


Composite thickness


Transversal displacement peak


Longitudinal displacement peak


Ultimate transversal displacement


Ultimate total shortening of column


Geometrical slenderness


  1. 1.
    ACI 318 (2004) Building code requirements for structural concrete (ACI 318-05) and Commentary (ACI 318R-05), American Concrete Institute, DetroitGoogle Scholar
  2. 2.
    ACI 440.2R-08 (2008) Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI Committee 440, American Concrete InstituteGoogle Scholar
  3. 3.
    Attari N, Si Youcef Y (2003) Le Séisme du 21 mai 2003 à BOUMERDES, Colloque international fabrication, gestion et pratiques des territoires. Ecole d’Architecture de Paris Val de SeineGoogle Scholar
  4. 4.
    Benzaid R (2010) Contribution à l’étude des matériaux composites dans le renforcement et la réparation des éléments structuraux linéaires en béton, these de doctorat. IUT de Rennes, FranceGoogle Scholar
  5. 5.
    CEB-FIP (1978) Buckling and instability, Comité Euro-Intenational du Béton, Prepared by Comite Euro- International du Béton (CEB) in Cooperation with Fédération Internationale de la Précontrainte (FIP). The Construction Press, LancasterGoogle Scholar
  6. 6.
    Chaallal O, Shahawy M and Al-Saad N (2000) Behaviour of axially loaded short rectangular columns strengthened with CFRP composite wrapping. FDOT, Structures Research Center, TallahasseeGoogle Scholar
  7. 7.
    Chaallal O, Hassan M, Shahawy M (2003) Confinement model for axially loaded short rectangular columns strengthened with fiber-reinforced polymer wrapping. ACI Struct J 100(2):215–221Google Scholar
  8. 8.
    Chai YH, Priestley MJN, Seible F (1991) Seismic retrofit of circular bridge columns for enhanced flexural performance. ACI Struct J 88(5):572–584Google Scholar
  9. 9.
    Chemrouk M, Attari N and Si Youcef Y (2005) Lessons from the Boumerdes-Algiers earthquake, (ISBN 0 7277 3403 2), 787. Thomas Telford Edition, LondonGoogle Scholar
  10. 10.
    De Lorenzis L (2001) A comparative study of models on confinement of concrete cylinders with FRP composites. Chalmers University of Technology, Division of Building Technology, Work No 46. Publication 01:4. Göteborg, 2001-06-30, p 73Google Scholar
  11. 11.
    De Lorenzis L, Tepfers R (2003) Comparative study of models on confinement of concrete cylinders with fiber-reinforced polymer composites. ASCE J Compos Constr 7(3):219–237CrossRefGoogle Scholar
  12. 12.
    De Lorenzis L, Tamužs V, Tepfers R, Valdmanis V and Vilks U (2004) Stability of CFRP-confined columns, Ed. IMTCR 2004. Innovative Materials and Technologies for Construction and Restoration Conference, Lecce, pp 327–342Google Scholar
  13. 13.
    Eurocode 2 (2004) Calcul des structures en béton—Partie 1-1: Règles générales et règles pour les bâtiments, Normalisation françaiseGoogle Scholar
  14. 14.
    FitzWilliam J, Bisby L (2010) Slenderness effect on circular CFRP confined reinforced concrete column. J Compos Constr 14(3):280–288CrossRefGoogle Scholar
  15. 15.
    Hadi MNS (2005) Behaviour of FRP wrapped normal strength concrete columns under eccentric loading. Compos Struct 72(1):503–511Google Scholar
  16. 16.
    Jiang T, Teng J (2012) Behavior and design of slender FRP-confined circular RC columns. J Compos Constr 17(4):443–453CrossRefGoogle Scholar
  17. 17.
    Kim J, Yi S, Park C, Eo S (1999) Size effect on compressive strength of plain and spirally reinforced concrete cylinders. ACI Struct J 96(1):88–96Google Scholar
  18. 18.
    Li J, Hadi MNS (2003) Behavior of externally confined high strength concrete columns under eccentric loading. J Compos Struct 62:145–153CrossRefGoogle Scholar
  19. 19.
    MacLean D I and Bernards L L (1992) Seismic retrofitting of rectangular bridge column for shear. Final Report (WA-RD 255.1). Washington State Department of Transportation, OctGoogle Scholar
  20. 20.
    Norris T, Saadatmanesh H (1997) Shear and flexural strengthening of R/C beams with carbon fiber sheets. J Struct Eng 123(7):903–911CrossRefGoogle Scholar
  21. 21.
    Park R, Paulay T (1975) Reinforced concrete structures. Wiley, New YorkCrossRefGoogle Scholar
  22. 22.
    Parvin A, Wang W (2001) Behavior of FRP jacketed concrete columns under eccentric loading. J Compos Constr 5(3):146–152CrossRefGoogle Scholar
  23. 23.
    Pfrang EO, Siess CP, Sozen MA (1964) Load–moment–curvature characteristics of reinforced concrete cross sections. J Am Concr Inst 61(7):763–777Google Scholar
  24. 24.
    Rousakis TC, Rakitzis TD, Karabinis AI (2012) Design-oriented strength model for FRP-confined concrete members. J Compos Constr 16(6):615–625CrossRefGoogle Scholar
  25. 25.
    Sheikh SA, DeRose D, Mardukhi J (2002) Retrofitting of concrete structures for shear and flexure with fiber-reinforced polymers. ACI Struct J 99(4):451–459Google Scholar
  26. 26.
    Saadatmanesh H, Ehsani MR, Li MW (1994) Strength and ductility of concrete columns externally reinforced with fiber composite straps. J Am Concr Inst 91(4):434–447Google Scholar
  27. 27.
    Si Youcef Y (2010) Contribution à la comprehension du comportement des poteaux élanés en béton armé confinés et renforcés par la fibre de carbone, these de doctorat, LIMATB, Université de Bretagne Sud, FranceGoogle Scholar
  28. 28.
    Si Youcef Y, Amziane S and Chemrouk M (2008) The influence of CFRP on the behavior of reinforced concrete subjected to buckling, CICE 2008, Zurich, Switzerland: Fourth International Conference on FRP Composites in Civil Engineering, pp 22–24Google Scholar
  29. 29.
    Si Youcef Y, Amziane S and Chemrouk M (2008) Influence of the geometry on the effectiveness of confinement using CFRP. International Congress Beton 2008. IstanbulGoogle Scholar
  30. 30.
    Si Youcef Y, Amziane S and Chemrouk M (2009) Influence of the geometry on the effectiveness of confinement using CFRP, (Porto UO Éd). Fifteenth International Conference on Composite Structures, Porto, 15–17 June 2009Google Scholar
  31. 31.
    Si Youcef Y, Amziane S, Chemrouk M (2010) Geometrical effect on the behavior of CFRP confined and unconfined concrete columns. J Reinf Plast Compos 29(17):2621–2635CrossRefGoogle Scholar
  32. 32.
    SikaFrance-1 (2007) SikaWrap-230C, Tissu de fibres de carbone pour renforcement de structures, N 9.80, février 2007Google Scholar
  33. 33.
    SikaFrance-2 (2007) Sikadur-330C, Résine d’imprégnation pour tissu de renforcement, N 9.97, février 2007Google Scholar
  34. 34.
    Tamužs V, Valdmanis V, Tepfers R, Gylltoft K (2008) Stability analysis of CFRP-wrapped columns strengthened with external longitudinal CFRP sheets. Mech Compos Mater 44(3):199–208CrossRefGoogle Scholar
  35. 35.
    Toutanji HA (1999) Stress strain characteristics of concrete columns externally confined with advanced composites. ACI Mater J 96(3):397–403Google Scholar
  36. 36.
    Verok K (2005) Renforcement des structures en béton armé à l’aide de matériaux composites : étude de frettage et application these de doctorat. Ecole Nationale des Ponts et Chaussées, ParisGoogle Scholar
  37. 37.
    Wang YC, Restrepo JI (2001) Investigation of concentrically loaded reinforced concrete columns confined with glass fiber-reinforced polymer jackets. ACI Struct J 6(3):377–385Google Scholar
  38. 38.
    Yan Z, Pantelides CP, Reaveley LD (2006) Fiber-reinforced polymer jacketed and shape-modified compression members: I—experimental behavior. ACI Struct J 103(6):885–893Google Scholar

Copyright information

© RILEM 2013

Authors and Affiliations

  1. 1.Ecole Polytechnique d’Architecture et d’UrbanismeAlgiersAlgeria
  2. 2.Institut Pascal, UMR 6602Clermont University, University Blaise PascalAubiereFrance
  3. 3.Université des Sciences et de la Technologie Houari BoumedieneBab-EzzouarAlgeria

Personalised recommendations