Journal of the Architectural Institute of Korea Structure & Construction (대한건축학회논문집:구조계)

Architectural Institute of Korea (대한건축학회)
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Experimental Studies of Effect of Beam Sizes and CFRP Layers on Structural Behaviors of Reinforced Concrete Beams Strengthened with CFRPs (Carbon Fiber Reinforced Polymers)

탄소섬유 시트로 휨 보강된 철근 콘크리트 보에서 보 크기와 보강 겹수가 구조 거동에 미치는 영향에 대한 실험 연구

  • 김희선 (이화여자대학교 건축공학과)
  • Received : 2012.08.28
  • Published : 2012.11.25
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Abstract

The purpose of this study is to investigate beam size effect on structural behaviors of RC beams strengthened with CFRPs. Toward this goal, RC beams having different sizes are fabricated and strengthened with CFRPs. Beam lengths are 3200mm and 4600mm. Amount of steel bar and CFRP (Carbon Fiber Reinforced Polymers) reinforcements are controlled in order to unify reinforcing ratios of tested beams. From the tests, structural behaviors such as cracks and beam failure modes are observed. Also, displacements and strains on FRPs and reinforcing steel bars are measured from the tests. The experimental results show that CFRP sheet is able to increase load capacity of reinforced concrete beams by 30~50%, however strengthening effect significantly decreases as number of CFRP sheets increases due to debonding failure of the CFRPs. Also, no significant influence by beam sizes can be found from beginning of normalized load-deflection curves. In relatively small sized beams, slight differences are found such that first crack is delayed and interfacial stresses is reduced.

Keywords

Acknowledgement

Supported by : 한국연구재단

References

  1. 김진율 외, "CFRP가 보강된 철근콘크리트 보의 거동과 연성", 한국콘크리트학회 논문집, 제 19권 2호, 2007, pp.225-231.
  2. 박상렬, "부착길이와 복부정착이 CFRP판으로 보강된 RC보의 휨 보강효과에 미치는 영향", 한국콘크리트학회 논문집, 제 14권 5호, 2002, pp.645-652.
  3. 박종섭 외, "탄소섬유쉬트에 의해 휨보강된 RC보의 휨강도 추정", 한국콘크리트학회 논문집, 제 17권 2호, 2005, pp.213-220
  4. 안상호, 이상호, "FRP로 보강된 철근콘크리트 보의 휨 보강설계", 대한건축학회논문집 구조계, 제 21권 5호, 2005, pp.51-58
  5. 우투이 나디아, "하이브리드 FRP 부착성능에 관한 연구" 석사학위 논문, 2012, 이화여자대학교.
  6. 이원호, 임재형, "탄소섬유시트로 보강된 철근콘크리트 보의 휨내력 평가에 관한 실험연구", 대한건축학회논문집 구조계, 제 21권 6호, 2005, pp.3-10.
  7. 최기선 외,"RC보의 휨보강 설계를 위한 CFRP의 보강매수에 따른 부분감소계수", 대한건축학회 학술발표대회 논문집, 제22권 1호, 2002년 4월 27일, pp.91-94.
  8. Brena SF, Marcri BM. Effect of carbon-fiber-reinforce polymer laminate configuration on the behavior of strengthened reinforced concrete beams. Journal of composites for construction 2004;8: 229-240. https://doi.org/10.1061/(ASCE)1090-0268(2004)8:3(229)
  9. Gao B, Kim JK, Leung CKY. Effect of tapered FRP sheets on interlaminar fracture behavior of FRP concrete interface. Composites Part A 2006;37(10): 1605-612. https://doi.org/10.1016/j.compositesa.2005.10.010
  10. Gartner A, Douglas EP, Dolan CW, Hamilton HR. Small beam bond test method for CFRP composites applied to concrete. Journal of Composites for Construction 2010;15(1): 52-61.
  11. Hashemi SH, Maghsoudi AA, Rahgozar R. Bending response of HSRC beams strengthened with FRP sheets. Transacion A: Civil Engineering 2009;16(2): 138-146.
  12. Kadhim MMA. Effect of CFRP sheet length on the behavior of HSC continuous Beam. Journal of Thermoplastic Composite Materials 2011:1-12.
  13. Kim HS, Shin YS. Flexural behavior of RC (RC) beams retrofitted with hybrid fiber reinforced polymers (FRPs) under sustaining loads. Composite Structures 2011; 93(2): 802-811. https://doi.org/10.1016/j.compstruct.2010.07.013
  14. Leung CKY. FRP debonding from a concrete substrate: Some recent findings against conventional belief. Cement&Concrete Composites 2006;2: 742-748.
  15. Li LJ, Guo YC, Liu F, Bungey JH. An experimental and numerical study of the effect of thickness and length of CFRP on performance of repaired reinforced concrete beams. Construction and Building Materials 2006;20: 901-909. https://doi.org/10.1016/j.conbuildmat.2005.06.020
  16. Maalej M, Leong KS. Effect of beam size and FRP thickness on interfacial shear stress concentration and failure mode of FRP-strengthened beams. Composites Science and Technology 2005;65: 1148-1158. https://doi.org/10.1016/j.compscitech.2004.11.010
  17. Qu Z, Lu XZ, Ye LP, Size effect of shear contribution of externally bonded FRP U-Jackets for RC beams. Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005), 2005; 363-372
  18. Smith S, Teng JG. FRP-retrofitted RC beams I: review of debonding strength models. Engineering Structures 2002;24(4): 385-395. https://doi.org/10.1016/S0141-0296(01)00105-5
  19. Smith S, Teng JG. FRP-retrofitted RC beams II: assessment of debonding strength models. Engineering Structures 2002;24(4): 397-417. https://doi.org/10.1016/S0141-0296(01)00106-7
  20. Teng JG, Chen JF, Smith ST, Lam L. FRP retrofitted RC structures. John Wiley & Sons, Inc 2001.