KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Crack Spacing in RC Tension Members Considering Cover Thickness and Concrete Compressive Strength

피복두께와 콘크리트 강도를 고려한 철근콘크리트 인장부재의 균열간격

  • 김우 (전남대학교 토목공학과) ;
  • 이기열 (순천제일대학교 토목조경과)
  • Received : 2017.10.24
  • Accepted : 2018.02.05
  • Published : 2018.04.01
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Abstract

This paper proposed a crack spacing calculation formulation which is an important parameter for calculating the crack width, that is the main factor for verification of serviceability limit states and durability performance evaluation of reinforced concrete members. The basic equation of average crack spacing is derived by considering the bond characteristics which is the governing equation for the analysis of cracking behavior in reinforced concrete members. In order to consider the effect of the cover thickness and concrete compressive strength, the crack spacing measured in 124 direct tensile tests performed by several researchers was analyzed and each coefficient was proposed. And, correlation analysis was performed from 80 specimen data where the maximum and average crack spacing were simultaneously measured, and a correlation coefficient that can easily predict the maximum crack spacing from the average crack spacing was proposed. The results of the proposed average crack spacing equation and maximum crack spacing correlation were compared with those current design code specification. The comparisons of proposed equations and the Korean design codes show that the proposed formulation for the average crack spacing and the maximum crack spacing improves the accuracy and reliability of prediction compared to the corresponding provisions of the Korean Concrete Structural Design Code and Korean Highway Bridge Design Code (Limit States Design).

이 연구는 철근콘크리트 부재에서 사용한계상태 검증 및 내구성능 평가의 요소인 균열폭을 계산하는데 중요한 변수가 되는 균열간격 계산식을 제안한 것이다. 철근콘크리트 부재의 균열거동 해석을 위한 지배방정식이 되는 부착특성을 반영하여 평균균열간격 기본식을 유도하고, 피복두께와 콘크리트 강도의 영향을 고려할 수 있도록 여러 연구자들이 수행한 124개의 직접인장실험에서 측정된 균열간격을 분석하여 각각의 계수를 제안하였다. 그리고, 최대 및 평균 균열간격이 동시에 측정된 80개의 실험체 자료로부터 상관관계 분석을 실시하여 평균균열간격으로부터 최대 균열간격을 간편하게 예측할 수 있는 상관계수를 제안하였다. 제안된 평균균열간격 계산식 및 최대균열간격 상관식에 대해서 현행 설계기준의 규정과 비교를 실시하였다. 비교 결과, 평균균열간격 및 최대균열간격에 대한 제안식은 콘크리트구조기준 및 도로교설계기준(한계상태설계법)의 해당 규정과 비교하여 예측의 정확성 및 신뢰도가 개선됨을 확인하였다.

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References

  1. Abrishami, H. H. and Mitchell, D. (1996). "Influence of splitting cracks on tension stiffening." ACI Structural Journal, Vol. 93, No. 6, pp. 703-710.
  2. Broms, B. B. (1965). "Crack width and crack spacing in reinforced concrete members." ACI Journal, Vol. 62, No. 9, pp. 1237-1256.
  3. CEB-FIP (1990). "CEB-FIP model code 1990." Comite Euro- International du Beton, Thomas Telford.
  4. Deluce, J. R. and Vecchio, F. J. (2013). "Cracking behavior of steel fiber-reinforced concrete members containing conventional reinforcement." ACI Structural Journal, Vol. 110, No. 3, pp. 481-490.
  5. Deluce, J. R., Lee, S. C. and Vecchio, F. J. (2014). "Cracking model for steel fiber-reinforced concrete members containing conventional reinforcement." ACI Structural Journal, Vol. 111, No. 1, pp. 93-102.
  6. European Committee for Standardization (2002). "EUROCODE 2 - design of concrete structures." European Committee for Standardization, Brussels.
  7. Fields, K. and Bishoff, P. H. (2004). "Tension stiffening and cracking of high-strength reinforced concrete tension members." ACI Structural Journal, Vol. 101, No. 4, pp. 447-456.
  8. Forth, J. H. and Beeby, A. W. (2014). "Study of composite behavior of reinforcement and concrete in tension." ACI Structural Journal, Vol. 111, No. 2, pp. 397-406.
  9. Goto, Y. (1971). "Cracks Formed in Concrete Around Deformed Tension Bars." ACI Journal, Vol. 68, No. 4, pp. 244-251.
  10. Hong, C. H. (1999). Development of Tension Stiffening Models for Steel Fibrous High Strength Reinforced Concrete and Its Application into Nonlinear Analysis, Dissertation of Ph.D., Kangwon University (in Korean).
  11. Kim, D. H. (2011). Cracking Behavior of Concrete by Rib Shapes of Reinforcement, Dissertation of M.S., Youngnam University (in Korean).
  12. Kim, W., Lee, K. Y. and Mun, I. (2001). "Bond characteristics and cracking behavior in high-strength concrete tensile members-modeling of bond characteristics." Journal of the KSCE, Vol. 21, No. 5-A, pp. 244-251 (in Korean).
  13. Korea Concrete Institute (2007). Concrete Structural Design Code, Kimoondang Publishing Co. Ltd. (in Korean).
  14. Korea Concrete Institute (2012). Design Specifications for Structural Concrete, Kimoondang Publishing Co. Ltd. (in Korean).
  15. Korea Road and Transportation Association (2012). Korean Highway Bridge Design Code(Limit States Design Method) (in Korean).
  16. Korea Road and Transportation Association (2016). Korean Highway Bridge Design Code(Limit States Design Method) (in Korean).
  17. Korean Institute of Bridge and Structural Engineers and Korea Bridge Design and Engineering Research Center (2015). Manual of Korean Highway Bridge Design Code(Limit States Design Method) (in Korean).
  18. Lee, B. H. (1998). An Experimental Study on the Tension Stiffening Effect of Reinforced Concrete Members, Dissertation of Ph.D., Hanyang University (in Korean).
  19. Lee, G. Y. (2001). A Study on the Influence of Cover Thickness on Tension Stiffening Behavior, Dissertation of M.S., Chonnam National University (in Korean).
  20. Lee, G. Y. and Kim, W. (2009). "Cracking and tension stiffening behavior of high-strength concrete tension members subjected to axial load." Advances in Structural Engineering, Vol. 12, No. 2, pp. 127-137. https://doi.org/10.1260/136943309788251614
  21. Lorrain, M., Maurel, O. and Seffo, M. (1998). "Cracking behavior of reinforced high-strength concrete tension ties." ACI Structural Journal, Vol. 95, No. 5, pp. 626-635.
  22. Perera, S. V. T. J. and Mutsuyoshi, H. (2011). "Tension stiffening behavior of high-strength concrete tension members." Annual Research Journal of SLSAJ, Vol. 11, pp. 10-18.
  23. Rizkalla, S. H. and Hwang, L. S. (1984). "Crack prediction for members in uniaxial tension." ACI Journal, Vol. 81, No. 6, pp. 572-579.
  24. Russo, G. and Romano, F. (1992). "Cracking response of rc members subject to uniaxial members." ASCE Journal of Structural Engineering, Vol. 118, No. 5, pp. 1172-1190. https://doi.org/10.1061/(ASCE)0733-9445(1992)118:5(1172)
  25. Yun, S. H. (1999). A Study on the Tension Stiffening Effect in High-Strength Concrete, Dissertation of M.S., Chonnam National University (in Korean).