Structural Engineering and Mechanics

  • 제67권1호
  • /
  • Pages.45-52
  • /
  • 2018
  • /
  • 1225-4568(pISSN)
  • /
  • 1598-6217(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Experimental investigation on optimal shear strengthening of RC beams using NSM GFRP bars

  • Ramezanpour, M. (Department of Civil Engineering, Yazd University) ;
  • Morshed, R. (Department of Civil Engineering, Yazd University) ;
  • Eslami, A. (Department of Civil Engineering, Yazd University)
  • 투고 : 2017.05.10
  • 심사 : 2018.04.18
  • 발행 : 2018.07.10
⟨ 이전 논문 다음 논문 ⟩

초록

Several techniques have been developed for shear strengthening of reinforced concrete (RC) members by using fiber reinforced polymer (FRP) composites. However, debonding of FRP retrofits from concrete substrate still deemed as a challenging concern in their application which needs to be scrutinized in details. As a result, this paper reports on the results of an experimental investigation on shear strengthening of RC beams using near surface mounted (NSM) FRP reinforcing bars. The main objective of the experimentation was increasing the efficiency of shear retrofits by precluding/postponing the premature debonding failure. The experimental program was comprised of six shear deficient RC beams. The test parameters include the FRP rebar spacing, inclination angle, and groove shape. Also, an innovative modification was introduced to the conventional NSM technique and its efficiency was evaluated by experimental observation and measurement. The results testified the efficiency of glass FRP (GFRP) rebars in increasing the shear strength of the test specimens retrofitted using conventional NSM technique. However, debonding of FRP bars impeded exploiting all retrofitting advantages and induced a premature shear failure. On the contrary, application of the proposed modified NSM (MNSM) technique was not only capable of preventing the premature debonding of FRP bars, but also could replace the failure mode of specimen from the brittle shear to a ductile flexural failure which is more desirable.

키워드

참고문헌

  1. ACI Committee 440 (2008), Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-08), Farmington Hills, Michigan, U.S.A.
  2. Anil, O., Belgin, C.M. and Kara, M.E. (2010), "Experimental investigation on CFRP-to-concrete bonded joints across crack", Struct. Eng. Mech., 35(1), 1-18. https://doi.org/10.12989/sem.2010.35.1.001
  3. ASTM A370 (2017), Standard Test Methods and Definitions for Mechanical Testing of Steel Products, American Society for Testing and Materials, West Conshohocken, Pennsylvania, U.S.A.
  4. Baji, H., Eslami, A. and Ronagh, H.R. (2015), "Development of a nonlinear FE modelling approach for FRP-strengthened RC beam-column connections", Struct., 3, 272-281. https://doi.org/10.1016/j.istruc.2015.06.003
  5. Barros, J.A. and Dias, S.J. (2003), "Shear strengthening of reinforced concrete beams with laminate strips of CFRP", Proceedings of the International Conference Composites in Constructions.
  6. Bianco, V., Monti, G. and Barros, J.A. (2014), "Design formula to evaluate the NSM FRP strips shear strength contribution to a RC beam", Compos. Part B: Eng., 56, 960-971. https://doi.org/10.1016/j.compositesb.2013.09.001
  7. Chajes, M.J., Thomson, T.A., Januszka, T.F. and Finch, W.W. (1994), "Flexural strengthening of concrete beams using externally bonded composite materials", Constr. Build. Mater., 8(3), 191-201. https://doi.org/10.1016/S0950-0618(09)90034-4
  8. CSA (2012), Design and Construction of Building Structures with Fibre-Reinforced Polymers, CSA-S806-12, Canadian Standards Association, Mississauga, Ontario, Canada.
  9. Dalalbashi, A., Eslami, A. and Ronagh, H.R. (2012), "Plastic hinge relocation in RC joints as an alternative method of retrofitting using FRP", Compos. Struct., 94(8), 2433-2439. https://doi.org/10.1016/j.compstruct.2012.02.016
  10. Dalalbashi, A., Eslami, A. and Ronagh, H.R. (2013), "Numerical investigation on the hysteretic behavior of RC joints retrofitted with different CFRP configurations", J. Compos. Constr., 17(3), 371-382. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000361
  11. De Lorenzis, L. and Nanni, A. (2001), "Shear strengthening of reinforced concrete beams with near-surface mounted fiberreinforced polymer rods", ACI Struct. J., 98(1), 60-68.
  12. Deng, J., Airong, L., Peiyan, H. and Xiaohong, Z. (2016), "Interfacial mechanical behaviors of RC beams strengthened with FRP", Struct. Eng. Mech., 58(3), 577-596. https://doi.org/10.12989/sem.2016.58.3.577
  13. Dias, S.J. and Barros, J.A. (2013), "Shear strengthening of RC beams with NSM CFRP laminates: Experimental research and analytical formulation", Compos. Struct., 99, 477-490. https://doi.org/10.1016/j.compstruct.2012.09.026
  14. El-Mihilmy, M.T. and Tedesco, J.W. (2000), "Analysis of reinforced concrete beams strengthened with FRP laminates", J. Struct. Eng., 126(6), 684-691. https://doi.org/10.1061/(ASCE)0733-9445(2000)126:6(684)
  15. Eslami, A. and Ronagh, H.R. (2014), "Experimental investigation of an appropriate anchorage system for flange-bonded carbon fiber-reinforced polymers in retrofitted RC beam-column joints", J. Compos. Constr., 18(4), 04013056. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000456
  16. Jalali, M., Sharbatdar, M.K., Chen, J.F. and Alaee, F.J. (2012), "Shear strengthening of RC beams using innovative manually made NSM FRP bars", Constr. Build. Mater., 36, 990-1000. https://doi.org/10.1016/j.conbuildmat.2012.06.068
  17. Khalifa, A., Gold, W.J., Nanni, A. and Mi, A.A. (1998), "Contribution of externally bonded FRP to shear capacity of RC flexural members", J. Compos. Constr., 2(4), 195-202. https://doi.org/10.1061/(ASCE)1090-0268(1998)2:4(195)
  18. Kocak, A. (2015), "Earthquake performance of FRP retrofitting of short columns around band-type windows", Struct. Eng. Mech., 53(1), 1-16. https://doi.org/10.12989/sem.2015.53.1.001
  19. Kocak, A., Onal, M.M. and Sonmez, K. (2007), "Repairing and strengthening methods for RC structural members", Proceedings of the 6th International Conference on Fracture Mechanics of Concrete and Concrete Structures, Volume 2: Design, Assessment and Retrofitting of RC Structures, Catania, Italy.
  20. Mahini, S.S. and Ronagh, H.R. (2011), "Web-bonded FRPs for relocation of plastic hinges away from the column face in exterior RC joints", Compos. Struct., 93(10), 2460-2472. https://doi.org/10.1016/j.compstruct.2011.04.002
  21. Mahini, S.S. and Ronagh, H.R. (2010), "Strength and ductility of FRP web-bonded RC beams for the assessment of retrofitted beam-column joints", Compos. Struct., 92(6), 1325-1332. https://doi.org/10.1016/j.compstruct.2009.09.006
  22. Mosallam, A.S. and Banerjee, S. (2007), "Shear enhancement of reinforced concrete beams strengthened with FRP composite laminates", Compos. Part B-Eng., 38(5-6), 781-793. https://doi.org/10.1016/j.compositesb.2006.10.002
  23. Mostofinejad, D. and Mahmoudabadi, E. (2010), "Grooving as alternative method of surface preparation to postpone debonding of FRP laminates in concrete beams", J. Compos. Constr., 14(6), 804-811. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000117
  24. Onal, M.M., Zengin, B., Kocak, A. and Doran, B. (2014), "An experimental investigation on flexural behavior of RC beams strengthened with different techniques", KSCE J. Civil Eng., 18(7), 2162-2169. https://doi.org/10.1007/s12205-014-1353-x
  25. Rizzo, A. and De Lorenzis, L. (2009), "Behavior and capacity of RC beams strengthened in shear with NSM FRP reinforcement", Constr. Build. Mater., 23(4), 1555-1567. https://doi.org/10.1016/j.conbuildmat.2007.08.014
  26. Teng, J., Huang, Y., Lam, L. and Ye, L. (2007), "Theoretical model for fiber-reinforced polymer-confined concrete", J. Compos. Constr., 11(2), 201-210. https://doi.org/10.1061/(ASCE)1090-0268(2007)11:2(201)

피인용 문헌

  1. Comparative Investigation on Torsional Behaviour of RC Beam Strengthened with CFRP Fabric Wrapping and Near-Surface Mounted (NSM) Steel Bar vol.2019, pp.None, 2018, https://doi.org/10.1155/2019/9061703
  2. Torsional Strengthening of RC Beams with Near-Surface Mounted Steel Bars vol.2020, pp.None, 2018, https://doi.org/10.1155/2020/1492980
  3. Torsional Strengthening of RC Beams with Continuous Spiral Near-Surface Mounted Steel Wire Rope vol.14, pp.1, 2018, https://doi.org/10.1186/s40069-019-0386-4
  4. Shear strengthening of reinforced concrete beams using NSM/EBR techniques vol.12, pp.1, 2021, https://doi.org/10.12989/acc.2021.12.1.063
  5. Experimental investigation and strength model of RC deep beams externally bonded by CFRP vol.24, pp.16, 2018, https://doi.org/10.1177/13694332211010583