한국구조물진단유지관리공학회 논문집 (Journal of the Korea institute for structural maintenance and inspection)

  • 제15권5호
  • /
  • Pages.178-189
  • /
  • 2011
  • /
  • 2234-6937(pISSN)
  • /
  • 2287-6979(eISSN)
한국구조물진단유지관리공학회 (Korea Institute for Structural Maintenance Inspection)
권호 표지
DOI QR코드

DOI QR Code

CFRP 스트립 표면매립공법으로 보강된 철근콘크리트 보의 전단거동 특성

Characteristics of Shear Behavior of Reinforced Concrete Beams Strengthened with Near Surface Mounted CFRP Strips

  • 투고 : 2011.04.21
  • 심사 : 2011.07.02
  • 발행 : 2011.09.30
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

본 연구에서는 CFRP 표면부착 공법의 대안으로 최근에 관심을 끌고 있는 NSM(Near Surface Mounted)기법으로 전단 보강된 RC 부재의 전단강도를 평가하기 위한 실험과 해석을 수행하였다. 전단철근이 없는 7개의 실험체에 대해 4점 휨실험을 실시하였다. 실험변수로는 CFRP 스트립의 경사($45^{\circ}$, $90^{\circ}$)와 스트립의 간격(250mm, 200mm, 150mm, 100mm)이 고려되었다. 실험적 연구를 통해 NSM공법으로 전단 보강된 RC 부재의 전단강도와 파괴모드에 대한 각 실험변수의 영향을 평가하였다. 실험결과는 $45^{\circ}$ 경사로 스트립을 보강한 실험체들은 스트립의 파단으로 파괴된 반면, 수직으로 스트립을 보강한 실험체들은 스트립의 슬립으로 파괴됨을 보였다. 또한, $45^{\circ}$ 경사 스트립이 수직 스트립보다 전단저항력 증가시킬뿐만 아니라 파괴시의 처짐을 크게 증가시키는 것으로 나타났다. 추가적으로 RBSN 해석은 NSM기법으로 전단 보강된 RC 부재의 균열형상 및 하중-처짐관계를 적절하게 예측하였다.

Tests and analyses were performed in this study to assess the shear strength of Reinforced Concrete(RC) members strengthened by the Near Surface Mounted(NSM) technique in shear, which is drawing attention as an alternative to the Carbon Fiber Reinforced Polymer(CFRP) bonding strengthening technique. Four-point bending tests were performed on 7 RC specimens without any shear reinforcement. The test variables such as the inclination of CFRP strip (45 degrees and 90 degrees), and the spacing of CFRP strip (250mm, 200mm, 150mm, 100mm) were considered. Through the testing scenarios, the effect of each test variable on the failure mode and the shear strength of the RC members strengthened by the NSM technique in shear were assessed. The test results show that the specimens with CFRP strips at 45 degrees go to failure as a result of the strip fracture, but the specimens with CFRP strips at 90 degrees go to failure as a result of the slip of strips. Strips at 45 degrees was the more effective than strips at 90 degrees, not only in terms of increasing beam shear resistance but also in assuring larger deformation capacity at beam failure. In addition, the RBSN analysis appropriately predicted the crack formation and the load-displacement response of the RC members strengthened by the NSM technique in shear.

키워드

참고문헌

  1. 박상렬, "탄소 FRP 쉬트로 휨 보강된 R.C 보의 보강효과에 관한 연구", 대한토목학회논문집, 제21권 6A호, 2001, pp.997-1005.
  2. 박중열, 조홍동, 한상훈, "탄소섬유판으로 휨보강된 철근콘크리트 보의 비선형거동 예측", 대한토목학회논문집, 제24권 1-A호, 2004, pp.9-16.
  3. 이재훈, 신성진, "전단보강이 없는 FRP RC 보의 전단강도 예측", 한국콘크리트학회논문집, 제22권, 3호, 2010, pp.311-324.
  4. 임동환, 권영순, "표면매입 및 외부부착 탄소섬유판으로 보강된 철근콘크리트 부재의 전단 거동에 관한 실험적 연구", 한국콘크리트학회논문집, 제21권 3호, 2009, pp.337-345.
  5. 임동환, 남민희, "탄소섬유판 (CFRP Strip)으로 보강된 철근 콘크리트 부재의 전단거동", 한국콘크리트학회논문집, 제20권 3호, 2008, pp.299-305.
  6. Barros, J. A. O., Dias S. J. E., "Near surface mounted CFRP laminates for shear strengthening of concrete beams", Cement and Concrete Composites, vol. 28, No. 3, 2006, pp.276-292. https://doi.org/10.1016/j.cemconcomp.2005.11.003
  7. Bolander, J., Saito, S., "Fracture Analysis using Spring Networks with Random Geometry", Engineering Fracture Mechanics, vol. 61, 1998, pp.569-591. https://doi.org/10.1016/S0013-7944(98)00069-1
  8. De Lorenzis L., Nanni A., "Bond between near-surface mounted FRP rods and concrete in structural strengthening", ACI Structural Journal, vol. 99, No. 2, 2002, pp.123-133.
  9. Dias, S. J. E., Barros, J. A. O., "Shear strengthening of RC T-section beams with low strength concrete using NSM CFRP laminates", Cement and Concrete Composites 33, 2011, pp.334-345. https://doi.org/10.1016/j.cemconcomp.2010.10.002
  10. Hsu, T. T. C., "Unified Theory of Reinforced Concrete", CRC Press, 1993, pp. 205-217.
  11. Kawai, T., "New Discrete Models and Their Application to Seismic Response Analysis of structures", Nuclear Engineering and Design, vol. 48, 1978, pp.207-229. https://doi.org/10.1016/0029-5493(78)90217-0
  12. Kishi, N., Zhang G., Mikami, H., "Numerical Cracking and Debonding Analysis of RC Beams Reinforced with FRP Sheet", ASCE, 9:6, 2005, pp.498-507.
  13. Nanni, A., Di Ludovico, M. and Parretti, R., "Shear Strengthening of PC Bridge with NSM CFRP Rectangular Bars", Adv Struct Engr., vol. 7, No. 4, 2004, pp.97-109.
  14. Nakamura, H., Higai, T., "Compressive Fracture Energy and Fracture Zone Length of Concrete", In: Modeling of inelastic behavior of RC structures under seismic load, ASCE, 2001, pp.471-487.
  15. Neale, K. W., Ebead, U. A., Abdel Baky, H. M., Elsayed, W. E. and Godat, A., "Modelling of Debonding Phenomena in FRP-Strengthened Concrete Beams and Slabs", International Institute for FRP in Construction, BBFS 2005.
  16. Rizzo, A., De Lorenzis, L., "Modeling of debonding failure for RC beams strengthened in shear with NSM FRP reinforcement", Construction and Building Materials, vol. 23, 2009, pp.1568-1577. https://doi.org/10.1016/j.conbuildmat.2008.03.009
  17. Rizzo, A., De Lorenzis, L., "Behavior and capacity of RC beams strengthened in shear with NSM FRP reinforcement", Construction and Building Materials, vol. 23, 2009, pp.1555-1567. https://doi.org/10.1016/j.conbuildmat.2007.08.014
  18. Saito, S., "Fracture Analyses of Structural Concrete using Spring Network with Random Geometry", Doctoral Thesis, Department of Civil Engineering, Kyushu University, 1999.
  19. Shima, H., Okamura, H., "Bond-Slip-Strain Relationship of Deformed Bars Embedded in Massive Concrete", Proceeding of the Japan Society of Civil Engineers, JSCE, vol. 6, No. 378, 1987, pp.165-174.
  20. Tanarslan H. M., "The effects of NSM CFRP reinforcements for improving the shear capacity of RC beams", Construction and Building Materials, vol. 25, 2011, pp.2663-2673. https://doi.org/10.1016/j.conbuildmat.2010.12.016
  21. Wu, Z., Li, W., Sakuma N., "Innovative externally bonded FRP/concrete hybrid flexural members", Composite Structures, 72, 2006, pp.289-300. https://doi.org/10.1016/j.compstruct.2004.12.002

피인용 문헌

  1. Post-Tensioning Steel Rod System for Flexural Strengthening in Damaged Reinforced Concrete (RC) Beams vol.8, pp.10, 2018, https://doi.org/10.3390/app8101763