Mechanics of Composite Materials

, Volume 44, Issue 3, pp 279–288 | Cite as

Strengthening of RC beams with an innovative timber-FRP composite system

  • N. Mazzon
  • M. Guadagnini
  • M. R. Valluzzi


The results of a theoretical and experimental research project on the use of an innovative technique for strengthening concrete beams are presented. A spacer element is inserted between the tension side of a beam and the composite material to increase its lever arm and to enhance the over all stiffness of the strengthened beam. The main aim of this exploratory project was to increase the ultimate failure load of strengthened beam specimens, whilst guaranteeing acceptable over all deflections at the serviceability limit states. This resulted into a significant reduction in the amount of FPR required and in a better utilization of the materials employed. A preliminary theoretical study was carried out to investigate the effect of Young’s modulus, failure strain, and thickness of the element to be used as a spacer in order to determine the best possible candidate material. Three tests on 2.5-m-long beams were carried out, and different anchorage techniques were used to try and prevent the debonding of the strengthening system. The results from this pilot study are very promising, as the strengthening system ensures an adequate initial stiffness along with an improved ultimate flexural capacity.


beam FRP timber strengthening serviceability limit state deflection crack width flexural behaviour 


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  1. 1.
    J. Brody, A. Richard, K. Sebesta, K. Wallace, Yong Hong, R. L. Anido, W. Davids, and E. Landis, “FRP-wood-concrete composite bridge girders,” Structures 2000-103, 189, Advanced Engineered Wood Composites Center, University of Maine, Orono, ME (2000).Google Scholar
  2. 2.
    A. W. Craig, C. D. William, and J. D. Habib, “Testing and analysis of partially composite fiber-reinforced polymer-glulam-concrete bridge girders,” J. Bridge Eng., 9, Iss. 4, 316–325 (2004).Google Scholar
  3. 3.
    M. Brunner, C. Gerber, Holz-Beton-Verbundelemente durch die Anwendung von Klebesystemen, KTI Projekt 3953.1, interim report, SWOOD, Biel-Bienne (July, 1999).Google Scholar
  4. 4.
    V. Nardini, “Anchorage strength models for end debonding prediction in RC beams strengthened with FRP composites,” Tesi di laurea, Department of Civil Engineering, University of Padova (September, 2006).Google Scholar
  5. 5.
    Comitato Nazionale di Ricerca (CNR), Istruzioni per la Progettazione, l’Esecuzione ed il Controllo di Interventi di Consolidamento Statico mediante l’utilizzo di Compositi Fibrorinforzati, CNR-DT 200/2004, Roma (luglio 2004).Google Scholar
  6. 6.
    International Federation for Structural Concrete (fib), “Technical Report on the Design and Use of Externally Bonded Fibre-Reinforced Polymer Reinforcement (FRP EBR) for Reinforced Concrete Structures,” Task Group 9.3 FRP Reinforcement for Concrete Structures, Bulletin 14 (July, 2001).Google Scholar
  7. 7.
    ISIS Canada, Design Manual No. 4 — Strengthening Reinforced Concrete Structures with Externally-Bonded Fibre-Reinforced Polymers, The Canadian Network of Centres of Excellence on Intelligent Sensing for Innovative Structures (2001).Google Scholar
  8. 8.
    The Concrete Society, Design Guidance for Strengthened Concrete Structures Using Fibre Composite Materials, Technical Report No. 55 (2000).Google Scholar
  9. 9.
    American Concrete Institute (ACI), Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures — ACI.440.2R-02, ACI Committee 440 (2002).Google Scholar
  10. 10.
    B. H. Ahmadi, and M. P. Saka, “Behaviour of composite timber-concrete floors,” J. Struct. Eng., 119, No. 10, 3111–3130 (1993).CrossRefGoogle Scholar
  11. 11.
    R. Capozucca, “Bond stress system of composite concrete-timber beams,” Mater. Struct., 3, No. 1, 634–640 (1998).CrossRefGoogle Scholar
  12. 12.
    M. Demarzo and M. Tacitano, Semirigid Wood-Concrete T-Beams, M.S. Dissertation — Fac. de Eng. Civil, UNICAMP, Campinas, Sao Paulo, Brasil (2002).Google Scholar
  13. 13.
    A. W. Craig, Behaviour of FRP-Reinforced Glulam-Concrete Bridge Girders, Thesis for a Degree in MSc in Civil Engineering, University of Maine (May, 2002).Google Scholar
  14. 14.
    G. D. William, “Non-linear analysis of FRP-glulam-concrete beams with partial composite action,” J. Struct. Eng., 127, Iss. 8, 967–971 (2001).Google Scholar

Copyright information

© Springer Science+Business Media, Inc. 2008

Authors and Affiliations

  • N. Mazzon
    • 1
  • M. Guadagnini
    • 2
  • M. R. Valluzzi
    • 1
  1. 1.Department of Civil EngineeringUniversity of PaduaPaduaItaly
  2. 2.Department of Civil and Structural EngineeringUniversity of SheffieldSheffield, South YorkshireUK

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