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

Architectural Institute of Korea (대한건축학회)
권호 표지
DOI QR코드

DOI QR Code

Analysis and Design Method of Reinforced Concrete Beams Strengthened with Externally Unbonded Steel Rods

강봉으로 보강된 철근콘크리트 보의 해석 및 설계방법

  • 이정민 (경북대 건축.토목공학부) ;
  • 신경재 (경북대 건축.토목공학부) ;
  • 이희두 (경북대 건축.토목공학부) ;
  • 이수헌 (경북대 건축.토목공학부)
  • Received : 2012.06.27
  • Published : 2012.11.25
⟨ Previous Next ⟩

Abstract

This study presents an analysis design method after evaluating the flexural behavior of reinforced concrete (RC) beams with externally unbonded steel rods. It is necessary to evaluate the plastic hinge length, because the plastic hinge length is important to find the deflection of RC beams strengthened with unbonded rods and predict the maximum strain of steel rods at ultimate state. The analysis of RC beams strengthened with unbonded rods is difficult because the strain of externally unbonded steel rods is an unknown value from the conventional strain compatibility of the section. So it would be obtained from the elongation due to beam deflection using the plastic hinge length. In order to simplify of the analysis of RC beams strengthened, it is assumed that unbonded steel rods are the same as double layer reinforcing of tension steel. This method will provide an appropriate design method of RC beams strengthened for designers.

Keywords

Acknowledgement

Supported by : 한국연구재단, 경북대학교

References

  1. 대한건축학회, 건축구조설계기준, 기문당, 2009
  2. 이정민, 강봉으로 보강된 철근콘크리트 보의 해석 및 설계 방법, 경북대학교 석사학위논문, 2012
  3. Lee, S.H., Experimental and Numerical Studies of Reinforced Concrete Beams Strengthened with Externally Prestressing Steel Rods, Ph.D. Thesis, Kyungpook National University, 2011
  4. 신경재, 김윤정, 문정호, 고장력 인장봉으로 보강된 RC보의 휨거동에 관한 실험적 연구(3), 한국콘크리트학회 논문집, 19권, 3호, p.p. 351-358, 2007
  5. Corley, W.G., Rotational Capacity of Reinforced Concrete Beams, Journal of the Structural Division, ASCE, Vol.92, No.ST5, p.p. 121-146, 1966
  6. Harajli, M.H., On the Stress in Unbonded Tendons at Ultimate: Critical Assessment and Proposed Changes, ACI Structural Journal, Vol.103, No.6, p.p. 803-812, 2006
  7. Mattock, A.H., Discussion of rotational capacity of reinforced concrete beams by Corley, W.G., Journal of the Structural Division, ASCE, Vol.93, No.ST2, p.p. 519-533, 1967
  8. Parretti, R. and Nanni, A., Strengthening of RC Members using Near-Surface Mounted FRP Composites: Design Overview, Advances in Structural Engineering, Vol.7, No.5, p.p. 1-16, 2004 https://doi.org/10.1260/136943304322985729
  9. Sawyer, H.A., Design of Concrete Frames for Two Failure State, Proceedings of the International Symposium on the Flexural Mechanics of Reinforced Concrete, ASCE-ACI, Miami, p.p. 405-431, 1964
  10. Shin, K.J., Lee, S.H., Kang, T.H.-K., Analysis of prestressing rod systems for strengthening RC beams, The 2011 World Congress on Advances in Structural Engineering and Mechanics (ASEM' 11PLUS), p.p. 962-974, 2011
  11. Shin, K.J. and Lee, S.H., Flexural behaviour of RC beams strengthened with high-tension steel rod, Magazine of Concrete Research, Vol.62, No.2, p.p. 137-147, 2010 https://doi.org/10.1680/macr.2008.62.2.137
  12. Yost, J.R., Gross, S.P., Dinehart, D.W., and Mildenberg, J.J.,Flexural Behavior of Concrete Beams Strengthened with Near-Surface-Mounted CFRP Strips, ACI Structural Journal, Vol.104, No.4, p.p. 430-437, 2007
  13. Yu, P., Silva, P.F., and Nanni, A., Description of a Mechanical Device for Prestressing of Carbon Fiber-Reinforced Polymer Sheets- Part I, ACI Structural Journal, Vol.105, No.1, p.p. 3-10, 2008a
  14. Yu, P., Silva, P.F., and Nanni, A., Flexural Strength of Reinforced Concrete Beams Strengthened with Prestressed Carbon Fiber-Reinforced Polymer Sheets- PartII, ACI Structural Journal, Vol.105, No.1, p.p. 11-20, 2008b