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Modelling of Factors Affecting Bond Strength of Fibre Reinforced Polymer Externally Bonded to Timber and Concrete

Authors: Abbas Vahedian, Rijun Shrestha, Keith Crews


In recent years, fibre reinforced polymers as applications of strengthening materials have received significant attention by civil engineers and environmentalists because of their excellent characteristics. Currently, these composites have become a mainstream technology for strengthening of infrastructures such as steel, concrete and more recently, timber and masonry structures. However, debonding is identified as the main problem which limit the full utilisation of the FRP material. In this paper, a preliminary analysis of factors affecting bond strength of FRP-to-concrete and timber bonded interface has been conducted. A novel theoretical method through regression analysis has been established to evaluate these factors. Results of proposed model are then assessed with results of pull-out tests and satisfactory comparisons are achieved between measured failure loads (R2 = 0.83, P < 0.0001) and the predicted loads (R2 = 0.78, P < 0.0001).

Keywords: Debonding, FRP, pull-out test, stepwise regression analysis.

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[1] Shrestha, R., Behaviour of RC beam-column connections retrofitted with FRP strips, in Faculty of Engineering and Information Technology. 2009, University of Technology Sydney.
[2] Hollaway, L.C. and J.-G. Teng, Strengthening and rehabilitation of civil infrastructures using fibre-reinforced polymer (FRP) composites. 2008, North America by CRC Press: Elsevier Reference Monographs.
[3] D’Ambrisi, A., F. Focacci, and R. Luciano, Experimental investigation on flexural behavior of timber beams repaired with CFRP plates. Composite Structures, 2014. 108: p. 720-728.
[4] Juvandes, L. and R. Barbosa, Bond Analysis of Timber Structures Strengthened with FRP Systems. Strain, 2012. 48(2): p. 124-135.
[5] Valipour, H.R. and K. Crews, Efficient finite element modelling of timber beams strengthened with bonded fibre reinforced polymers. Construction and Building Materials, 2011. 25(8): p. 3291-3300.
[6] Khelifa, M. and A. Celzard, Numerical analysis of flexural strengthening of timber beams reinforced with CFRP strips. Composite Structures, 2014. 111: p. 393-400.
[7] Wu, Z. and S. Hemdan. Debonding in FRP Strengthened Flexural Members with Different Shear-Span Ratios. in Proceeding of the 7th International Symposium on Fiber Reinforced Composite Reinforcement for Concrete Structures. 2005. Michigan, USA.
[8] Cao, S., et al., ESPI measurement of bond-slip relationships of FRP-concrete interface. Journal of Composites for Construction, 2007. 11(2): p. 149-160.
[9] Mazzotti, C., M. Savoia, and B. Ferracuti, An experimental study on delamination of FRP plates bonded to concrete. Construction and Building Materials, 2008. 22(7): p. 1409-1421.
[10] Dai, J., T. Ueda, and Y. Sato, Unified analytical approaches for determining shear bond characteristics of FRP-concrete interfaces through pullout tests. Journal of Advanced Concrete Technology, 2006. 4(1): p. 133-145.
[11] Ferracuti, B., M. Savoia, and C. Mazzotti, Interface law for FRP–concrete delamination. Composite structures, 2007. 80(4): p. 523-531.
[12] Chen, J. and J. Teng, Anchorage strength models for FRP and steel plates bonded to concrete. Journal of Structural Engineering, 2001. 127(7): p. 784-791.
[13] Wan, J., An investigation of FRP-to-timber bonded interfaces, in Civil Engineering. 2014, The University of Hong Kong Pokfulam, Hong Kong.
[14] Hiroyuki, Y. and Z. Wu, Analysis of debonding fracture properties of CFS strengthened member subject to tension, in Non-Metallic (FRP) Reinforcement for Concrete Structures, Proceedings of the Third Symposium. 1997: Sapporo, Japan. p. 287–294.
[15] Tanaka, T., Shear resisting mechanism of reinforced concrete beams with CFS as shear reinforcement. 1996, Hokkaido University: Japan.
[16] Maeda, T., et al. A study on bond mechanism of carbon fiber sheet. in Non-Metallic (FRP) Reinforcement for Concrete Structures, Proceedings of the Third Symposium. 1997. Sapporo, Japan.
[17] Custódio, J., J. Broughton, and H. Cruz, A review of factors influencing the durability of structural bonded timber joints. International journal of adhesion and adhesives, 2009. 29(2): p. 173-185.
[18] Mier, J.G.V., Concrete fracture: a multiscale approach. 2012: CRC press.
[19] Gustafsson, P., Analysis of generalized Volkersen-joints in terms of non-linear fracture mechanics. 1987, Paris. p. 139-150.
[20] Holzenkämpfer, P., Ingenieurmodelle des Verbunds geklebter Bewehrung für Betonbauteile in Institut für Baustoffe, Massivbau und Brandschutz. 1994, Technische Universität Braunschweig: Braunschweig, Germany.
[21] Niedermeier, R., Stellungnahme zur richtlinie für das verkleben von betonbauteilen durch ankleben von stahllaschen–entwurf märz 1996, in Schreiben 1390 vom 30.10. 1996 des Lehrstuhls für Massivbau. 1996: Technische Universität München, Munich, Germany (in German).
[22] Blaschko, M., R. Niedermeier, and K. Zilch. Bond failure modes of flexural members strengthened with FRP. in Fiber Compos. in Infrastruct, 2nd International Conference on Composites in Infrastructure. 1996.
[23] DIN1048, Augsgabe 6.91,, in Teil 2: Prüfverfahren für Beton, Festbeton in Bauwerken und Bauteilen. 1991, Deutsches Institut für Normung, e.V. Beuth Verlag, Berlin (in German).
[24] Cevik, A., et al., Soft computing based formulation for strength enhancement of CFRP confined concrete cylinders. Advances in Engineering Software, 2010. 41(4): p. 527-536.
[25] Campbell, M.J., Statistics at square two: understanding modern statistical applications in medicine. 2006: BMJ Books/Blackwell.
[26] Ueda, T., Y. Sato, and Y. Asano, Experimental study on bond strength of continuous carbon fiber sheet. ACI Special Publication, 1999. 188.
[27] Ren, H., Study on basic theories and long time behavior of concrete structures strengthened by fiber reinforced polymers. 2003, Dalian University of Technology: Dalian, China.
[28] Wu, Z., et al., Experimental/analytical study on interfacial fracture energy and fracture propagation along FRP-concrete interface. ACI Special Publications, 2001. 201: p. 133-152.
[29] Zhou, Y., Analytical and experimental study on the strength and ductility of FRP-reinforced high strength concrete beam. 2009, Dalian University of Technology, Dalian, China.
[30] Yao, J., J. Teng, and J. Chen, Experimental study on FRP-to-concrete bonded joints. Composites Part B: Engineering, 2005. 36(2): p. 99-113.
[31] Reddy, M.V., Statistical Methods in Psychiatry Research and SPSS. 2014: CRC Press.
[32] Lawrence, K.D., R.K. Klimberg, and S.M. Lawrence, Fundamentals of forecasting using excel. 2009: Industrial Press Inc.
[33] Coronado, C., Characterization, modeling and size effect of concrete-epoxy interfaces, in Department of Civil and Environmental Engineering. 2006, The Pennsylvania State University.
[34] Lu, X., et al., Bond–slip models for FRP sheets/plates bonded to concrete. Engineering structures, 2005. 27(6): p. 920-937.
[35] Saxena, P., Interfacial bond behavior between FRP and concrete substrate, in Civil and Environmental Engineering. 2006, The University of Alabama in Huntsville, Huntsville, Alabama.
[36] Crews, K. and S.T. Smith. Tests on FRP-strengthened timber joints. in Proceedings, 3rd International Conference on FRP Composites in Civil Engineering, CICE 2006. 2006.