Computers and Concrete

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

A minimum ductility design method for non-rectangular high-strength concrete beams

  • Au, F.T.K. (Department of Civil Engineering, The University of Hong Kong) ;
  • Kwan, A.K.H. (Department of Civil Engineering, The University of Hong Kong)
  • Received : 2003.05.19
  • Accepted : 2004.02.02
  • Published : 2004.05.25
⟨ Previous Next ⟩

Abstract

The flexural ductility of solid rectangular reinforced concrete beams has been studied quite extensively. However, many reinforced concrete beams are neither solid nor rectangular; examples include T-, ${\Gamma}$-, ${\Pi}$- and box-shaped beams. There have been few studies on the flexural ductility of non-rectangular reinforced concrete beams and as a result little is known about the possible effect of sectional shape on flexural ductility. Herein, the effect of sectional shape on the post-peak flexural behaviour of reinforced normal and high-strength concrete beams has been studied using a newly developed analysis method that employs the actual stress-strain curves of the constitutive materials and takes into account the stress-path dependence of the stress-strain curve of the steel reinforcement. It was revealed that the sectional shape could have significant effect on the flexural ductility of a concrete beam and that the flexural ductility of a T-, ${\Gamma}$-, ${\Pi}$- or box-shaped beam is generally lower than that of a solid rectangular beam with the same overall dimensions and the same amount of reinforcement provided. Based on the numerical results obtained, a simple method of ensuring the provision of a certain minimum level of flexural ductility to non-rectangular concrete beams has been developed.

Keywords

Acknowledgement

Supported by : Croucher Foundation of Hong Kong

References

  1. Attard, M. M. and Setunge, S. (1996), "The stress strain relationship of confined and unconfined concrete", ACI Materials, 93(5), 432-444.
  2. Carreira, D. J. and Chu, K. H. (1986), "The moment-curvature relationship of reinforced concrete members", ACI, 83(2), 191-198.
  3. Gerald, C. F. and Wheatley, P. O. (1999), Applied Numerical Analysis, 6th Ed., Addison-Wesley, USA, 698pp.
  4. Ho, J. C. M., Kwan, A. K. H. and Pam, H. J. (2003), "Theoretical analysis of post-peak flexural behavior of normal- and high-strength concrete beams", Structural Design of Tall and Special Buildings, 12, 109-125. https://doi.org/10.1002/tal.216
  5. Ho, J. C. M., Kwan, A. K. H. and Pam, H. J. (2004), "Minimum flexural ductility design of high-strength concrete beams", Magazine of Concrete Research, 56(1), 13-22. https://doi.org/10.1680/macr.2004.56.1.13
  6. Kwan, A. K. H., Ho, J. C. M. and Pam, H. J. (2002), "Flexural strength and ductility of reinforced concrete beams", Proc., Institution of Civil Engineers, Structures and Buildings, 152(4), 361-369. https://doi.org/10.1680/stbu.2002.152.4.361
  7. Kwan, A. K. H., Ho, J. C. M. and Pam, H. J. (2004), "Effects of concrete grade and steel yield strength on flexural ductility of reinforced concrete beams", Australian Journal of Structural Engineering, 5(2), 119-138.
  8. Pam, H. J., Kwan, A. K. H. and Islam, M. S. (2001a), "Flexural strength and ductility of reinforced normal- and high-strength concrete beams", Proc., Institution of Civil Engineers, Structures and Buildings, 146(4), 381-389. https://doi.org/10.1680/stbu.2001.146.4.381
  9. Pam, H. J., Kwan, A. K. H. and Ho, J. C. M. (2001b), "Post-peak behavior and flexural ductility of doubly reinforced normal- and high-strength concrete beams", Struct. Eng. Mech., An int. J., 12(5), 459-474. https://doi.org/10.12989/sem.2001.12.5.459
  10. Park, R. and Paulay, T. (1975), Reinforced Concrete Structures; John Wiley & Sons, New York, USA, 769pp.
  11. Samra, R. M., Deeb, N. A. A. and Madi, U. R. (1996), "Transverse steel content in spiral concrete columns subjected to eccentric loading", ACI Struct., 93(4), 412-419.
  12. Skeikh, S.A. and Yeh, C. C. (1992), "Analytical moment-curvature relations for tied concrete columns", Struct. Eng., ASCE, 118(2), 529-544. https://doi.org/10.1061/(ASCE)0733-9445(1992)118:2(529)

Cited by

  1. Effects of strain hardening of reinforcement on flexural strength and ductility of reinforced concrete columns vol.20, pp.7, 2011, https://doi.org/10.1002/tal.554
  2. Effect of small axial force on flexural ductility design of high-strength concrete beams vol.24, pp.11, 2015, https://doi.org/10.1002/tal.1209
  3. Flexural ductility design of high-strength concrete columns vol.22, pp.1, 2013, https://doi.org/10.1002/tal.662
  4. Flexural ductility design of high-strength concrete beams vol.22, pp.6, 2013, https://doi.org/10.1002/tal.714
  5. Ductility of symmetrically reinforced concrete columns vol.61, pp.5, 2009, https://doi.org/10.1680/macr.2008.00149
  6. Ductility Design of High-Strength Concrete Beams and Columns vol.13, pp.4, 2010, https://doi.org/10.1260/1369-4332.13.4.651
  7. Concurrent flexural strength and ductility design of RC beams via strain-gradient-dependent concrete stress-strain curve vol.24, pp.9, 2015, https://doi.org/10.1002/tal.1203
  8. Parametric Study of Reinforced Concrete Column Cross-Section for Strength and Ductility vol.400-402, pp.1662-9795, 2008, https://doi.org/10.4028/www.scientific.net/KEM.400-402.269
  9. Complete moment-curvature relationship of reinforced normal- and high-strength concrete beams experiencing complex load history vol.2, pp.4, 2005, https://doi.org/10.12989/cac.2005.2.4.309
  10. Effect of axial load on flexural behaviour of cyclically loaded RC columns vol.3, pp.4, 2004, https://doi.org/10.12989/cac.2006.3.4.261
  11. Maximum axial load level and minimum confinement for limited ductility design of high-strength concrete columns vol.6, pp.5, 2004, https://doi.org/10.12989/cac.2009.6.5.357
  12. Maximum concrete stress developed in unconfined flexural RC members vol.8, pp.2, 2004, https://doi.org/10.12989/cac.2011.8.2.207
  13. Effect of confinement on flexural ductility design of concrete beams vol.20, pp.2, 2004, https://doi.org/10.12989/cac.2017.20.2.129