Steel and Composite Structures

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Elastic-plastic formulation for concrete encased sections interaction diagram tracing

  • Fenollosa, Ernesto (Department of Continuum Mechanics and Theory of Structures, Polytechnic University of Valencia) ;
  • Gil, Enrique (Department of Continuum Mechanics and Theory of Structures, Polytechnic University of Valencia) ;
  • Cabrera, Ivan (Department of Continuum Mechanics and Theory of Structures, Polytechnic University of Valencia) ;
  • Vercher, Jose (Department of Architectural Constructions, Polytechnic University of Valencia)
  • Received : 2014.04.16
  • Accepted : 2015.03.03
  • Published : 2015.10.25
⟨ Previous Next ⟩

Abstract

Composite sections design consists on checking that the point defined by axial load and bending moment keeps included within the surface enclosed by the section interaction curve. Eurocode 4 suggests a method for tracing this diagram based on the plastic stress distribution method. However curves obtained according to this criterion overvalue concrete encased sections bearing capacity, especially when axial force comes with high bending moment values, so a correction factor is required. This article proposes a method for tracing this diagram based on the strain compatibility method. When stresses on the section are integrated by considering the Navier hypothesis, the use of the materials nonlinear constitutive equations provides curves much more adjusted to reality. This process requires the use of rather complex software which might reveal as too complex for practitioners. Preserving the same criteria of an elastic-plastic stress distribution, this article presents alternative expressions to obtain the failure internal forces in five significant points of the interaction diagram having considered five different positions of the neutral axis. These expressions are simply enough for their practical application. Concordance of curves traced strictly relying on these five points with those obtained by computer assisted stress integration considering the strain compatibility method and even with Eurocode 4 weighted curves will be presented for three different cross-sections and two different concrete strengths, revealing very good results.

Keywords

References

  1. AISC (2005), Load and resistance factor design specification for structural steel buildings, American Institute of Steel Construction; Chicago, IL, USA.
  2. Aschheim, M., Hernandez-Montes, E. and Gil-Martin, L.M. (2007), "Optimal domains for strength design of rectangular sections for axial load and moment according to Eurocode 2", Eng. Struct., 29(8), 1752-1760. https://doi.org/10.1016/j.engstruct.2006.09.021
  3. BS 5400 (2005), Steel, concrete and composite bridges: Part 5: Code of practice for design of composite bridges, British Standards Institution; London, UK.
  4. Dundar, C., Tokgoz, S., Tanrikulu, A.K. and Baran, T. (2008), "Behavior of reinforced and concrete-encased composite columns subjected to biaxial bending and axial load", Build. Environ., 43(6), 1109-1120. https://doi.org/10.1016/j.buildenv.2007.02.010
  5. Ellobody, E. and Young, B. (2011), "Numerical simulation of concrete encased steel composite columns", J. Constr. Steel Res., 67(2), 211-222. https://doi.org/10.1016/j.jcsr.2010.08.003
  6. Ellobody, E., Young, B. and Lam, D. (2011), "Eccentrically loaded concrete encased steel composite columns", Thin. Wall. Struct., 49(1), 53-65. https://doi.org/10.1016/j.tws.2010.08.006
  7. Eurocode 2, EC2 (2004), Design of concrete structures. Part 1-1: General rules and rules for building, European Committee for Standardization; Brussels, Belgium.
  8. Eurocode 4, EC4 (2011), Design of composite steel and concrete structures. Part 1-1: General rules and rules for building, European Committee for Standardization; Brussels, Belgium.
  9. Fenollosa, E and Cabrera, I. (2013), "Analysis of composite section columns under axial compression and biaxial bending moments", In: Structures and Architecture: Concepts, Applications and Challenges; (Chapter 186), Taylor & Francis Group, London, UK. pp. 1498-1505.
  10. Griffis, L.G., Moore, W.P. and Associates, Inc. (2003), Steel design guide series 6. Load and resistance factor design of W-shapes encased in concrete, American Institute of Steel Construction.
  11. Johnson, R.P. (2004), Composite Structures of Steel and Concrete, Volume 1: Beams, Columns, Frames and Applications in Building, (3th Edition), Blackwell Publishing, Oxford, UK.
  12. Jung, I.K., Shim, C.S., Chung, Y.S., Min, J. (2005), "Experiments for the evaluation of P-M interaction curve of SRC composite columns", J. Kor. Soc. Civil Eng. Magazine, 25(3A), 555-563
  13. Kwak, H. and Kwak, J. (2010), "An improved design formula for biaxially loaded slender RC column", Eng. Struct., 32(1), 226-237. https://doi.org/10.1016/j.engstruct.2009.09.009
  14. Polatov, A. (2013), "Numerical simulation of elastic-plastic stress concentration in fibrous composites", Coupled Syst. Mech., Int. J., 2(3), 271-288 https://doi.org/10.12989/csm.2013.2.3.271
  15. Roik, K. and Bergmann, R. (1989), Eurocode 4: Composite columns. Report EC4/6/89; University of Bochum, Bochum, Germany.
  16. Saw, H.S. and Richard Liew, J.Y. (2000), "Assessment of current methods for the design of composite columns in buildings", J. Constr. Steel Res., 53(2), 121-147. https://doi.org/10.1016/S0143-974X(99)00062-0
  17. Shanmugam, N.E. and Lakshmi, B. (2001), "State of the art report on steel-concrete composite columns", J. Constr. Steel Res., 57(10), 1041-1080. https://doi.org/10.1016/S0143-974X(01)00021-9
  18. Soliman, K.Z., Arafa, A.I, and Elrakib, T.M. (2013), "Review of design codes of concrete encased steel short columns under axial compression", Housing Building National Research Center, 9(2), 134-143.
  19. Tokgoz, S. and Dundar, C. (2008), "Experimental tests on biaxially loaded concrete-encased composite columns", Steel Compos. Struct., Int. J., 8(5), 423-438. https://doi.org/10.12989/scs.2008.8.5.423
  20. Valach, P. and Gramblicka, S. (2007), "Theoretical and experimental analyses of composite steel-reinforced concrete (SRC) columns", Slovak J. Civil Eng., 1(4), 1-9.
  21. Whitney, C.S. and Cohen, E. (1956), "Guide for ultimate strength design of reinforced concrete", ACI J., 28(5), 445-490. [Proceedings V.53]

Cited by

  1. Stress-transfer in concrete encased and filled tube square columns employed in top-down construction vol.22, pp.1, 2016, https://doi.org/10.12989/scs.2016.22.1.063
  2. Experimental and analytical investigation of composite columns made of high strength steel and high strength concrete vol.33, pp.1, 2019, https://doi.org/10.12989/scs.2019.33.1.067