Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Investigation of the effects of connectors to enhance bond strength of externally bonded steel plates and CFRP laminates with concrete

  • Received : 2015.06.17
  • Accepted : 2016.02.16
  • Published : 2016.04.30
⟨ Previous Next ⟩

Abstract

Steel plates and carbon-fiber-reinforced polymer (CFRP) laminates or plates bonded to concrete substrates have been widely used for concrete strengthening. However, this technique cause plate debonding, which makes the strengthening system inefficient. The main objective of this study is to enhance the bond strength of externally bonded steel plates and CFRP laminates to the concrete surface by proposing new embedded adhesive and steel connectors. The effects of these new embedded connectors were investigated through the tests on 36 prism specimens. Parameters such as interfacial shear stress, fracture energy and the maximum strains in plates were also determined in this study and compared with the maximum value of debonding stresses using a relevant failure criterion by means of pullout test. The study indicates that the interfacial bond strength between the externally bonded plates and concrete can be increased remarkably by using these connectors. The investigation verifies that steel connectors increase the shear bond strength by 48% compared to 38% for the adhesive connectors. Thus, steel connectors are more effective than adhesive connectors in increasing shear bond strength. Results also show that the use of double connectors significantly increases interfacial shear stress and decrease debonding failure. Finally, a new proposed formula is modified to predict the maximum bond strength of steel plates and CFRP laminates adhesively glued to concrete in the presence of the embedded connectors.

Keywords

Acknowledgement

Supported by : Ministry of Higher Education (MOHE)

References

  1. ACI 440.2R (2008), Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete, Reported by ACI Committee 440.
  2. Ali, M.M., Oehlers, D.J., Griffith, M.C. and Seracino, R. (2008), "Interfacial stress transfer of near surfacemounted FRP-to-concrete joints", Eng. Struct., 30(7), 1861-1868. https://doi.org/10.1016/j.engstruct.2007.12.006
  3. Aykac, S., Kalkan, I. and Uysal, A. (2012), "Strengthening of reinforced concrete beams with epoxy-bonded perforated steel plates", Struct. Eng. Mech., Int. J., 44(6), 735-751. https://doi.org/10.12989/sem.2012.44.6.735
  4. Bank, L.C. and Arora, D. (2007), "Analysis of RC beams strengthened with mechanically fastened FRP (MF-FRP) strips", Compos. Struct., 79(2), 180-191. https://doi.org/10.1016/j.compstruct.2005.12.001
  5. Barros, J.A., Dias, S.J. and Lima, J.L. (2007), "Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams", Cement Concrete Compos., 29(3), 203-217. https://doi.org/10.1016/j.cemconcomp.2006.09.001
  6. Biscaia, H.C., Chastre, C. and Silva, M.A. (2013), "Linear and nonlinear analysis of bond-slip models for interfaces between FRP composites and concrete", Compos. Part B: Eng., 45(1), 1554-1568. https://doi.org/10.1016/j.compositesb.2012.08.011
  7. Bruckner, A., Ortlepp, R. and Curbach, M. (2008), "Anchoring of shear strengthening for T-beams made of textile reinforced concrete (TRC)", Mater. Struct., 41(2), 407-418. https://doi.org/10.1617/s11527-007-9254-9
  8. Canadian Standards Association (CAN) (2002), CSA-S806-02: Design and construction of building components with fibre-reinforced polymers, Canadian Standards Association; Mississauga, ON, Canada.
  9. Ceroni, F. (2010), "Experimental performances of RC beams strengthened with FRP materials", Construct. Build. Mater., 24(9), 1547-1559. https://doi.org/10.1016/j.conbuildmat.2010.03.008
  10. Ceroni, F., Pecce, M., Matthys, S. and Taerwe, L. (2008), "Debonding strength and anchorage devices for reinforced concrete elements strengthened with FRP sheets", Compos. Part B: Eng., 39(3), 429-441. https://doi.org/10.1016/j.compositesb.2007.05.002
  11. Chen, J.F. and Teng, J.G. (2001), "Anchorage strength models for FRP and steel plates bonded to concrete", J. Struct. Eng., 127(7), 784-791. https://doi.org/10.1061/(ASCE)0733-9445(2001)127:7(784)
  12. Dai, J., Ueda, T. and Sato, Y. (2005), "Development of the nonlinear bond stress-slip model of fiber reinforced plastics sheet-concrete interfaces with a simple method", J. Compos Construct., 9(1), 52-62. https://doi.org/10.1061/(ASCE)1090-0268(2005)9:1(52)
  13. EC 2-1 (2004), Eurocode 2: Design of concrete structures-Part 1: Common rules for building and civil engineering structures; prEN 1992-1, CEN (Comite Europeen de Normalisation), European Committee for Standardisation, Central Secretariat, Brussels, Belgium.
  14. FIB Bulletin 14 (2002), Externally bonded FRP reinforcement for RC structures; Task group 9.3, International Federation of Structural Concrete (FIB).
  15. Hao, S.W., Liu, Y. and Liu, X.D. (2012), "Improved interfacial stress analysis of a plated beam", Struct. Eng. Mech., Int. J., 44(6), 463-478.
  16. HB 305-2008 (2008), Design handbook for RC structures retrofitted with FRP and metal plates: Beams and slabs; Standards Australia: 476, Sydney, NSW 2001, Australia, 68 p.
  17. JSCE (2001), Japan Society of Civil Engineers: Recommendations for upgrading of concrete structures with use of continuous fiber sheets, Concrete Engineering Series, No. 41, Tokyo, Japan, 250 p.
  18. Kim, S.J. and Smith, S.T. (2009a), "Behaviour of handmade FRP anchors under tensile load in uncracked concrete", Adv. Struct. Eng., 12(6), 845-865. https://doi.org/10.1260/136943309790327716
  19. Kim, S.J. and Smith, S.T. (2009b), "Shear strength and behavior of FRP spike anchors in cracked concrete", Proceedings of the 9th International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures, FRPRCS-9: Sydney, Australia.
  20. Kim, S.J. and Smith, S.T. (2010), "Pullout strength models for FRP anchors in uncracked concrete", J. Compos. Constr., 14(4), 406-414. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000097
  21. Lee, J.H., Lopez, M.M. and Bakis, C.E. (2009), "Slip effects in reinforced concrete beams with mechanically fastened FRP strip", Cement Concrete Compos., 31(7), 496-504. https://doi.org/10.1016/j.cemconcomp.2009.04.008
  22. Luccioni, B.M., Lopez, D.E. and Danesi, R.F. (2005), "Bond-slip in reinforced concrete elements", J. Struct. Eng., 131(11), 1690-1698. https://doi.org/10.1061/(ASCE)0733-9445(2005)131:11(1690)
  23. Nakaba, K., Kanakubo, T., Furuta, T. and Yoshizawa, H. (2001), "Bond behavior between fiber-reinforced polymers laminates and concrete", ACI Struct. J., 98(3), 359-367.
  24. Ren, H.T. (2003), "Study on basic theories and longtime behavior of concrete structures strengthened by fiber reinforced polymers", Ph.D. Thesis; University of Technology, Dalian, China.
  25. Smith, S.T. and Teng, J.G. (2002), "FRP-strengthened RC structures-II: assessment of debonding strength models", Eng. Struct., 24(4), 397-417. https://doi.org/10.1016/S0141-0296(01)00106-7
  26. Smith, S.T. and Teng, J.G. (2003), "Shear-bending interaction in debonding failures of FRP-plated RC beams", Adv. Struct. Eng., 6(3), 183-199. https://doi.org/10.1260/136943303322419214
  27. Teng, J.G., Zhang, J.W. and Smith, S.T. (2002), "Interfacial stresses in reinforced concrete beams bonded with a soffit plate: A finite element study", Construct. Build. Mater., 16(1), 1-14. https://doi.org/10.1016/S0950-0618(01)00029-0
  28. Teng, J.G., Smith, S.T., Yao, J. and Chen, J.F. (2003), "Intermediate crack-induced debonding in RC beams and slabs", Construct. Build. Mater., 17(6), 447-462. https://doi.org/10.1016/S0950-0618(03)00043-6
  29. Ueda, T., Dai, J.G. and Sato, Y. (2003), "A nonlinear bond stress-slip relationship for FRP sheet-concrete interface", Proceedings of the International Symposium on Latest Achievement of Technology and Research on Retrofitting Concrete Structures, Volume 11320, pp. 113-120.
  30. Yao, J., Teng, J.G. and Chen, J.F. (2005), "Experimental study on FRP-to-concrete bonded joints", Compos.-Part B: Eng., 36(2), 99-113. https://doi.org/10.1016/j.compositesb.2004.06.001
  31. Yuan, H., Lu, X., Hui, D. and Feo, L. (2012), "Studies on FRP-concrete interface with hardening and softening bond-slip law", Compos. Struct., 94(12), 3781-3792. https://doi.org/10.1016/j.compstruct.2012.06.009
  32. Zhou, Y.W., Wu, Y.F. and Yun, Y. (2010), "Analytical modeling of the bond-slip relationship at FRPconcrete interfaces for adhesively-bonded joints", Compos. Part B: Eng., 41(6), 423-433. https://doi.org/10.1016/j.compositesb.2010.06.004

Cited by

  1. A New Approach of Shear Connectors to Delay Debonding of CFRP Laminates Used for Shear Strengthening of RС Beams vol.895, 2017, https://doi.org/10.4028/www.scientific.net/MSF.895.61
  2. Investigating loading rate and fibre densities influence on SRG - concrete bond behaviour vol.34, pp.6, 2020, https://doi.org/10.12989/scs.2020.34.6.877
  3. Experimental and numerical investigations on a novel plate anchorage system to solve FRP debonding problem in the strengthened RC beams vol.45, pp.None, 2016, https://doi.org/10.1016/j.jobe.2021.103413