DOI QR코드

DOI QR Code

Prediction of residual mechanical behavior of heat-exposed LWAC short column: a NLFE model

Obaidat, Yasmeen T.;Haddad, Rami H.

  • 투고 : 2015.02.15
  • 심사 : 2015.12.14
  • 발행 : 2016.01.25

초록

A NLFE model was proposed to investigate the mechanical behavior of short columns, cast using plain or fibrous lightweight aggregate concrete (LWAC), and subjected to elevated temperatures of up to $700^{\circ}C$. The model was validated, before its predictions were extended to study the effect of other variables, not studied experimentally. The three-dimensional NLFE model was developed using ANSYS software and involved rational simulation of thermal mechanical behavior of plain and fibrous LWAC as well as longitudinal and lateral steel reinforcement. The prediction from the NLFE model of columns' mechanical behavior, as represented by the stress-strain diagram and its characteristics, compared well with the experimental results. The predictions of the proposed models, considering wide range of lateral reinforcement ratios, confirmed the behaviors observed experimentally and stipulated the importance of steel confinement in preserving post-heating mechanical properties of plain and fibrous LWAC columns, being subjected to high temperature.

키워드

NLFE;fire;post-heating;mechanical properties;columns;lightweight concrete

참고문헌

  1. ACI Comitte 318 (2011), Building Code Requirements for Structural Concrete and Commentary (ACI 318-011), American Concrete Institute Detroit, MI.
  2. Ahmed, A.H. and Hasan, H.M.A. (2005), "Effect of cyclic heating on reinforced concrete thick slabs", Al-Rafidain Eng. J., 4(13), 35-51.
  3. ANSYS (2008), User's manual Version 11.0.
  4. Al-Nimry, H, Haddad, R., Afram, S., Abdel-Halim, M., Haddad, R.H. and Ashour, D.M. (2013), "Effectiveness of advanced composites in repair heat-damaged RC columns", Mater. Struct., 46, 1843-1860. https://doi.org/10.1617/s11527-013-0022-8
  5. Banthia, N. and Sappakittipakorn, M. (2007), "Toughness enhancement in steel fiber reinforced concrete through fiber hybridization", Cement Concrete Res., 37, 1366-1372. https://doi.org/10.1016/j.cemconres.2007.05.005
  6. Chen, B. and Liu, J. (2005), "Contribution of hybrid fibers on the properties of the high-strength lightweight concrete having good workability", Cement Concrete Res., 35(5), 913-917. https://doi.org/10.1016/j.cemconres.2004.07.035
  7. Demirbog, R. and Gu, R. (2003), "The effects of expanded perlite aggregate, silica fume and fly ash on the thermal conductivity of lightweight concrete", Cement Concrete Res., 33, 723-727. https://doi.org/10.1016/S0008-8846(02)01032-3
  8. Dwaikat, M.B. and Kodur, V.K.R. (2009), "Hydrothermal Model for Predicting Fire Induced Spalling in Concrete Structural Systems", Fire Saf. J., 44, 425-434. https://doi.org/10.1016/j.firesaf.2008.09.001
  9. Eurocode 4 (2005), Design of composite steel and concrete structures-Part 1-2: General rules-structure fire design, EN 1994-1-2, Final draft, European Committee for Standardization.
  10. Haddad, R. and Ashour, D. (2013), "Thermal performance of steel fibrous lightweight aggregate concrete short columns", J. Compos. Mater., 47(16), 2013-2025. https://doi.org/10.1177/0021998312453605
  11. Haddad, R.H., Shannag, M.J. and Moh'd, A. (2008), "Repair of heat-damaged RC shallow beams using advanced composites", Mater. Struct., 41(2), 287-29. https://doi.org/10.1617/s11527-007-9238-9
  12. Hossain, K.M.A. (2006), "Blended cement and lightweight concrete using scoria: mix design, strength, durability and heat Insulation characteristics", Phys. Sci., 1, 5-16.
  13. Huang, Z.H. (2010), "Modelling the bond between concrete and reinforcing steel in a fire", Eng. Struct., 32(11), 3660-69. https://doi.org/10.1016/j.engstruct.2010.08.010
  14. Hu, H.T. and Schnobrich, W.C. (1989), "Constitutive modeling of concrete by using nonassociated plasticity", J. Mater. Civil Eng., ASCE, 1(4), 199-216. https://doi.org/10.1061/(ASCE)0899-1561(1989)1:4(199)
  15. International Organization for the Development of Structural Concrete (FIP) (1983), FIP Manual of Lightweight Aggregate Concrete, John Wiley and Sons, Toronto, NY.
  16. Issa, M.S. and Anwar, H. (2004), "Structural behavior of high strength reinforced concrete columns exposed to direct fire", Proceeding of International Conference on Future Vision and Challenges for Urban Development, Egypt..
  17. Kayali, O. (2008), "Fly ash lightweight aggregates in high performance concrete", Constr. Build. Mater., 22, 2293-2299.
  18. Lawson, J.R., Phan, L.T. and Davis, F. (2000), "Mechanical properties of high performance concrete after exposure to elevated temperatures", Report, National Institute and Standards and Technology, IR 6475, National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA.
  19. Mander, J.B., Priestley, M.J.N. and Park, R. (1988), "Theoretical stress-strain model for confined concrete", Struct. Eng. J., ASCE, 114(8), 1804-26. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1804)
  20. Mouli, M. and Khelafi, H. (2008), "Performance characteristics of lightweight aggregates concrete containing natural pozzolan", Build. Environ., 43, 31-36. https://doi.org/10.1016/j.buildenv.2006.11.038
  21. Nizamuddin, Z. and Bresler, B. (1979), "Fire resistance of reinforced concrete slabs", J. Struct. Div., 8(105), 1653-1671.
  22. Omer, A. (2007), "Effects of elevated temperatures on properties of concrete", Fire Saf. J., 42, 516-522. https://doi.org/10.1016/j.firesaf.2007.01.003
  23. Pothisiri, T. and Panedpojaman, P. (2012), "Modeling of bonding between steel rebar and concrete at elevated temperatures", Constr. Build. Mater., 27(1), 130-140. https://doi.org/10.1016/j.conbuildmat.2011.08.014
  24. Seanz, L. (1964), "Discussion equation for the stress stain curve of concrete, By Desayi P, Krishnan S", ACI J., 61(3), 1229-1235.

피인용 문헌

  1. Repair of heat-damaged RC columns using carbon nanotubes modified CFRP vol.50, pp.2, 2017, https://doi.org/10.12989/sem.2016.57.2.265