Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
권호 표지
DOI QR코드

DOI QR Code

Flexural Performance of Slabs Strengthened by Fiber-Reinforced Polymer Sheet with Hydrophilic Epoxy

친수성 에폭시를 사용하여 FRP 시트로 보강된 슬래브의 휨거동 평가

  • Ju, Hyunjin (Department of Architectural Engineering, University of Seoul) ;
  • Han, Sun-Jin (Institute of Urban Science, University of Seoul) ;
  • Cho, Hae-Chang (Department of Architectural Engineering, University of Seoul) ;
  • Lee, Deuck Hang (Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign) ;
  • Kim, Kang Su (Department of Architectural Engineering, University of Seoul)
  • 주현진 (서울시립대학교 건축학부) ;
  • 한선진 (서울시립대학교 도시과학연구원) ;
  • 조해창 (서울시립대학교 건축학부) ;
  • 이득행 (일리노이주립대학교 토목환경공학부) ;
  • 김강수 (서울시립대학교 건축학부)
  • Received : 2015.09.14
  • Accepted : 2015.12.01
  • Published : 2016.02.29
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the hydrophilic chemical grout using silanol (HCGS) was introduced to overcome the limitations of conventional epoxy resin which have been used for strengthening reinforced concrete (RC) structures. Then, flexural tests on the RC slabs strengthened by FRP sheets were conducted. Three slab specimens were tested in this study; a control specimen with no strengthening, and two specimens strengthened by a typical epoxy resin or HCGS, respectively, as a binder between the slabs and the FRP sheets. In addition, an analytical model was developed to evaluate the flexural behavior of strengthened slab members, considering the horizontal shear force at the interface between concrete slabs and FRP sheets. The analysis results obtained from the proposed model indicated that the strengthened specimens showed fully composite behavior before their flexural failure. Especially, the specimen strengthened by HCGS, which can overcome the limitations of conventional epoxy resin, showed a similar flexural performance with that strengthened by a conventional epoxy resin.

이 연구에서는 철근콘크리트 구조물 보강의 결합재로서 기존의 에폭시 재료가 가지는 한계를 극복하기 위하여 개발된 실라놀기를 이용한 친수성 화학 그라우트재(hydrophilic chemical grout using silanol, HCGS)를 소개하고 FRP 시트 보강공법을 적용한 슬래브 부재의 휨 실험을 수행하였다. 보강공법이 적용되지 않은 기준실험체, 슬래브와 FRP 시트를 기존의 에폭시로 부착한 실험체, 그리고 HCGS를 적용하여 시트를 부착한 실험체를 각 1개씩 총 3개의 슬래브에 대한 실험연구를 수행하였다. 또한, FRP 시트로 휨 보강된 슬래브 부재의 해석에 적합하도록 계면 수평전단력을 고려할 수 있는 휨 거동 해석모델을 개발하였다. 해석모델로 실험체들의 거동을 평가한 결과, 보강 실험체들은 휨 파괴 시점 전까지 완전합성에 매우 근접한 거동을 나타내는 것으로 평가되었으며, 특히, HCGS를 적용한 보강 실험체는 기존 에폭시의 한계를 극복하는 특성을 가지면서도 에폭시를 적용한 실험체와 유사한 휨 보강 성능을 나타내었다.

Keywords

References

  1. Newman, A., Structural Renovation of Buildings: Methods, Details, and Design Examples, McGraw-Hill, 2001, p.867.
  2. Seo, S.Y., and Kim, M.S., "Bond Strength of Near Surface-Mounted FRP Plate in Concrete Corresponding to Space and Bond Length", Journal of the Korea Concrete Institute, Vol.25, No.1, 2013, pp.37-43. https://doi.org/10.4334/JKCI.2013.25.1.037
  3. Cho, C.G., "Nonlinear Analysis of FRP Strengthened Reinforced Concrete Columns by Force-Based Finite Element Model", Journal of the Korea Concrete Institute, Vol.25, No.5, 2013, pp.529-537. https://doi.org/10.4334/JKCI.2013.25.5.529
  4. Lee, J.Y., Hwang, H.B, and Doh, J.H., "Effective Strain of RC Beams Strengthened in Shear with FRP", Composites Part B: Engineering, Vol.42, No.2, 2012, pp.754-765.
  5. El-Mihilmy, M.T. and Tedesco, J.W., "Prediction of Anchorage Failure for Reinforced Concrete Beams Strengthened with Fiber-Reinforced Polymer Plates", ACI Structural Journal, Vol.98, No.3, 2001, pp.301-314.
  6. Smith, S.T., and Teng, J.G., "Interfacial Stresses in Plated Beams", Engineering Structures, Vol.23, No.7, 2001, pp.857-871. https://doi.org/10.1016/S0141-0296(00)00090-0
  7. Cai, C.S., Nie, J., and Shi, X.M., "Interface Slip Effect on Bonded Plate Repairs of Concrete Beams", Engineering Structures, Vol.29, No.6, 2007, pp.1084-1095. https://doi.org/10.1016/j.engstruct.2006.07.017
  8. Alam, M.S., Kanakubo, T., and Yasojima, A, "Shear-Peeling Bond Strength betweeen Continuous Fiber Sheet and Concrete", ACI Structural Journal, Vol.109, No.1, 2012, pp.75-82.
  9. Malek, A.M., Saadatmanesh, H., and Ehsani, M.R., "Prediction of Failure Load of R/C Beams Strengthened with FRP Plate Due to Stress Concentration at the Plate End", ACI Structural Journal, Vol.95, No.2, 1998, pp.142-152.
  10. Silfwerbrand, J., "Shear Bond Strength in Repaired Concrete Structures", Materials and Structures, Vol.36, No.6, 2003, pp.419-424. https://doi.org/10.1007/BF02481068
  11. Tsioulou, O.T., and Dritsos, S.E., "A Theoretical Model to Predict Interface Slip due to Bending", Materials and Structures, Vol.44, No.4, 2011, pp.825-843. https://doi.org/10.1617/s11527-010-9669-6
  12. Kwon, H.M., Nguyen, T.N., and Le, T.A., "Improvement of the Strength of Acrylic Emulsion Polymer-modified Mortar in High Temperature and High Humidity by Blast Furnace Slag", KSCE Journal of Civil Engineering, Vol.13, No.1, 2009, pp.23-30. https://doi.org/10.1007/s12205-009-0023-x
  13. Ko, H.B., and Sate, Y., "Analysis of FRP-Strengthened RC Members with Varied Sheet Bond Stress-Slip Models", Journal of Advanced Concrete Technology, Vol.2, No.3, 2004, pp.317-326. https://doi.org/10.3151/jact.2.317
  14. Gohnert, M., "Proposed Theory to Determine the Horizontal Shear between Composite Precast and in Situ Concrete", Cement & Concrete Composites, Vol.22, No.6, 2000, pp.469-476. https://doi.org/10.1016/S0958-9465(00)00050-0
  15. Ju, H., Lee, D.H., Cho, H.C., Kim, K.S., Yoon, S., and Seo, S.Y., "Application of Hydrophilic Silanol-Based Chemical Grout for Strengthening Damaged Reinforced Concrete Flexural Members," Materials, Vol.7, No.6, 2014, pp.4823-4844. https://doi.org/10.3390/ma7064823
  16. Plum, D.R., and Horne, M.R., "The Analysis of Continuous Composite Beams with Partial Interaction", Institution of Civil Engineers Proceedings, Vol.59, No.4, 1975, pp.625-643.
  17. Fabbrocino, G., Manfredi, G., and Cosenza, E., "Non-linear Analysis of Composite Beams under Positive Bending", Computers & Structures, Vol.70, No.1, 1999, pp.77-89. https://doi.org/10.1016/S0045-7949(98)00173-4
  18. Fabbrocino, G., Manfredi, G., and Cosenza, E., "Analysis of Continuous Composite Beams Including Partial Interaction and Bond", Journal of Structural Engineering, ASCE, Vol.126, No.11, 2000, pp.1288-1294. https://doi.org/10.1061/(ASCE)0733-9445(2000)126:11(1288)
  19. Callister, W.D., Materials Science and Engineering: An Introduction, 7th Ed., John Wiley & Sons, 2007, p.721.
  20. Newmark, N.M., Siess, C.P., and Viest, I.M., "Tests and Analysis of Composite Beams with Incomplete Interaction", Proceedings of the Society for Experimental Stress Analysis, Vol.9, No.1, 1951, pp.75-92.
  21. Saiidi, M., Vrontinos, S., and Douglas, B., "Model for the Response of Reinforced Concrete Beams Strengthened by Concrete Overlays", ACI Structural Journal, Vol.87. No.6, 1990, pp.687-695.
  22. Collins, M.P., and Mitchell, D., Prestressed Concrete Structures, Prentice-Hall, 1991, p.766.
  23. MacGregor, J.G., and Wight, J.K., Reinforced Concrete: Mechanics and Design, 4th Ed., Pearson Prentice Hall, 2009, p.1112.