DOI QR코드

DOI QR Code

Shear Strength Estimation Model for Reinforced Concrete Members

철근콘크리트 부재의 전단강도 산정모델

  • 이득행 (충북대학교 건축공학과) ;
  • 한선진 (서울시립대학교 건축학부) ;
  • 김강수 (서울시립대학교 건축학부)
  • Received : 2020.07.01
  • Accepted : 2020.09.25
  • Published : 2020.10.30

Abstract

This study presents a shear strength estimation model, in which the shear failure of a reinforced concrete (RC) member is assumed to be governed by the flexure-shear mechanism. Two shear demand curves and corresponding potential capacity curves for cracked tension and uncracked compression zones are derived, for which the bond mechanism developed between reinforcing bars and surrounding concrete is considered in flexural analysis. The shear crack concentration factor is also addressed to consider the so-called size effect induced in large RC members. In addition,unlike exising methods, a new formulation was addressed to consider the interaction between the shear contributions of concrete and stirrup. To verify the proposed method, an extensive shear database was established, and it appeared that the proposed method can capture the shear strengths of the collected test specimens regardless of their material properties, geometrical features, presence of stirrups, and bond characteristics.

이 연구에서는 철근콘크리트 부재의 전단파괴가 휨-전단 메커니즘에 지배된다는 가정을 바탕으로 인장측과 압축측에 대한 2개의 전단요구곡선들과 이에 대응되는 잠재전단강도곡선들을 각각 도출하였으며, 이를 기반으로 전단강도 산정모델을 제안하였다. 제안모델에서는 철근과 콘크리트의 부착거동을 고려하여 휨균열폭과 철근의 국부응력증가분을 산정하였다. 또한, 휨균열로부터 발전되는 지배전단균열의 생성과 균열진전거동을 이론적으로 모사하기 위하여 균열집중계수를 도입하였으며, 이를 통해 단면높이가 큰 철근콘크리트 부재에서 관측되는 크기효과를 반영하였다. 또한, 기존의 해석모델과는 다르게 전단철근과 콘크리트의 전단기여분 사이의 상호작용을 고려할 수 있는 새로운 형태의 수식을 개발하였다. 제안모델의 검증을 위하여 방대한 전단실험체들을 기존문헌으로부터 수집하였으며, 이를 통해 해석모델을 검증한 결과는 제안모델이 실험체들의 재료, 크기 및 철근의 부착특성에 관계없이 실험결과를 정확하게 평가할 수 있음을 보여주었다.

Keywords

References

  1. Joint ACI-ASCE Committee 445 (1998), Recent Approaches to Shear Design of Structural Concrete. State-of-the-Art Report by ASCE-ACI Committee 445 on Shear and Torsion, Journal of Structural Engineering, ASCE, 124(12), 1375-1417. https://doi.org/10.1061/(ASCE)0733-9445(1998)124:12(1375)
  2. Vecchio, F.J., and Collins, M.P. (1986), Modified Compression Field Theory for Reinforced Concrete Elements Subjected to Shear, ACI Journal Proceedings, 83(2), 219-231.
  3. Vecchio, F.J. (2000), Disturbed Stress Field Model for Reinforced Concrete: Formulation, Journal of Structural Engineering, ASCE, 126(9), 1070-1077. https://doi.org/10.1061/(ASCE)0733-9445(2000)126:9(1070)
  4. Muttoni, A., and Fernandez Ruiz, M. (2008), Shear Strength of Members without Transverse Reinforcement as a Function of the Critical Shear Crack Width, ACI Structural Journal, 105(2), 163-172.
  5. Vas Rodrigues, R.V., Muttoni, A., and Fernandez Ruiz, M. (2010), Influence of Shear on Rotation Capacity of Reinforced Concrete Members Without Shear Reinforcement, ACI Structural Journal, 107(5), 516-525.
  6. Park, H.G., Choi, K.K., and Wight, J.K. (2006), Strain-Based Shear Strength Model for Slender Beams without Web Reinforcement, ACI Structural Journal, 103(6), 783-793.
  7. Choi, K.K., Park, H.G., and Wight, J.K. (2007), Unified Shear Strength Model for Reinforced Concrete Beams-Part I: Development, ACI Structural Journal, 104(2), 142-152.
  8. Choi, K.K., Park, H.G., and Wight, J.K. (2007), Shear Strength of Steel Fiber-Reinforced Concrete Beams without Web Reinforcement, ACI Structural Journal, 104(1), 12-21.
  9. Kim, W., and Jeong, J.P. (2011), Decoupling of Arch Action in Shear-Critical Reinforced Concrete Beams, ACI Structural Journal, 108(4), 395-404.
  10. Collins, M.P., Mitchell, D., Adebar, P., and Vecchio, F.J. (1996), A General Shear Design Method, ACI Structural Journal, 93(1), 36-45.
  11. Collins, M.P. and Kuchma, D.A. (1999), How Safe Are Our Large, Lightly-Reinforced Concrete Beams, Slabs and Footings?, ACI Structural Journal, 96(4), 482-490.
  12. Bentz, E.C., Vecchio, F.J., and Collins, M.P. (2006), The Simplified MCFT for Calculating the Shear Strength of Reinforced Concrete Elements, ACI Structural Journal, 103(4), 614-624.
  13. Reineck, K.H. (1991), Ultimate Shear Force of Structural Concrete Members without Transverse Reinforcement Derived from Mechanical Model, ACI Structural Journal, 88(5), 592-602.
  14. Pang, X.B. and Hsu, T.T.C. (1996), Fixed Angle Softened Truss Model for Reinforced Concrete, ACI Structural Journal, 93(2), 197-207.
  15. Hsu, T.T.C. and Zhu, R.R.H. (2002), Softened Membrane Model for Reinforced Concrete Elements in Shear, ACI Structural Journal, 99(4), 460-469.
  16. Federation internationale du beton (2010), fib Model Code 2010, final draft. Bulletin Nos. 65 and 66.
  17. CSA Committee A23.3 (2004), Design of Concrete Structures (CSA A23.3-04), Canadian Standards Association, Mississauga, Canada.
  18. AASHTO (2004), AASHTO-LRFD Bridge Design Specifications and Commentary, 3rd Edition, American Association of State Highway Transportation Officials, Washington, D.C., USA.
  19. Trueyen, A.K. and Frosch, R.J. (2003), Concrete Shear Strength: Another Perspective, ACI Structural Journal, 100(5), 609-615.
  20. Kotsovos, M. D. (1998) Compressive Force Path Concept: Basis for Reinforced Concrete Ultimate Limit State Design, ACI Structural Journal, 85(1), 68-75.
  21. Kani, G.N.J. (1964), The Riddle of Shear Failure and Its Solution, ACI Journal Proceedings, 61(4), 441-467.
  22. Lee, D.H., Han, S.J., and Kim, K.S. (2016), Dual Potential Capacity Model for Reinforced Concrete Beams Subjected to Shear, Structural Concrete, 17(3), 443-456. https://doi.org/10.1002/suco.201500165
  23. Lee, D.H., Han, S.J., Hwang, J.H., Ju,H., and Kim, K.S. (2017), Simplification and Verification of Dual Potential Capacity Model for Reinforced Concrete Beams Subjected to Shear, Structural Concrete, 18(2), 259-277. https://doi.org/10.1002/suco.201600055
  24. Cho, S.H. (1998), CFT/MCFT from the Viewpoint of Strut-and-Tie Models, Journal of Korea Concrete Institute, 10(1), 40-48.
  25. Park, R. and Paulay, T. (1975), Reinforced Concrete Structures, John Wiley and Sons, New York, USA.
  26. Maaddawy, T.E., Soudki, K., and Topper, T. (2005), Analytical Model to Predict Nonlinear Flexural Behavior of Corroded Reinforced Concrete Beams, ACI Structural Journal, 102(4), 550-559.
  27. Han, S.J., Lee, D.H., Kim, K.S., Seo, S.Y., Moon, J.H., and Monteiro, P.J.M. (2014), Degradation of Flexural Strength in Reinforced Concrete Members Caused by Steel Corrosion, Construction and Building Materials, 54(1), 572-583. https://doi.org/10.1016/j.conbuildmat.2013.12.101
  28. Comite Euro-International du Beton (CEB) (1978), CEB-FIP Model Code for Concrete Structures, 3rd Edition, Paris, France.
  29. Collins, M.P. and Mitchell, D. (1991), Prestressed Concrete Structures, Prentice-Hall.
  30. Comite Euro-International du Beton (CEB) (1991), CEB-FIP Model Code, Thomas Telford, London, UK.
  31. ACI Committee 318 (2019), Building Code Requirements for Structural Concrete and Commentary (ACI 318-19), American Concrete Institute, Farmington Hills, Mich., USA.
  32. Lee, D.H., Han, S.J., Joo, H.E., Kim, K.S., Zhang, D., and Kim, J. (2020), Shear Crack Concentration in Reinforced Concrete Beam Subjected to Combined Shear and Flexure, Advances in Structural Engineering, doi.org/10.1177/1369433219895911.
  33. Sherwood, E.G., Bentz, E.C., and Collins, M.P. (2007), Effect of Aggregate Size on Beam-Shear Strength of Thick Slabs, ACI Structural Journal, 104(2), 180-191.
  34. Janaka Perera, S.V.T. and Mutsuyoshi, H. (2013), Shear Behavior of Reinforced High-Strength Concrete Beams, ACI Structural Journal, 110(1), 43-52.
  35. Kupfer, H., Hilsdorf, H K., and Rusch, H. (1969), Behavior of Concrete under Biaxial Stresses, ACI Journal Proceedings, 66(8), 656-666.
  36. Xie, L., Bentz, E.C., and Collins, M.P. (2011), Influence of Aixal Stress on Shear Response of Reinforced Concrete Elements, ACI Structural Journal, 108(6), 745-754.
  37. Frosch, A.K. (2000), Behavior of Large-Scale Reinforced Concrete Beams with Minimum Shear Reinforcement, ACI Structural Journal, 97(6), 814-820.
  38. Reineck, K.-H., Kuchma, D.A., Kim, K.S., and Marx, S. (2003), Shear Database for Reinforced Concrete Members without Shear Reinforcement, ACI Structural Journal, 100(2), 240-249.
  39. Reineck, K.H., Bentz, E., Birol, F., Kuchma, D., and Bayrak, O. (2014), ACI-DAfStb Databes for Shear Tests on Slender Reinforced Concrete Beams with Stirrups, ACI Structural Journal, 111(5), 1147-1156. https://doi.org/10.14359/51686819
  40. Kim, K. S. (2004), Shear Behavior of Reinforced Concrete Beams and Prestressed Concrete Beams, Ph.D. Dissertation, University of Illinois at Urbana-Champaign, USA.
  41. Collins, M.P., Bentz, E.C., Quach, P.T., and Proestos, G.T. (2015), The Challenge of Predicting the Shear Strength of Very Thick Slabs, Concrete International, 37(11), 29-37.