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Anisotropic Curvature and Damage of Unbonded Post-tensioned Concrete Slabs During Fire Testing

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Abstract

Two furnace tests, using two different fire exposures, on unbonded post-tensioned concrete slabs (1700 × 1200 mm) are reported. Local curvature is measured along two lines approximately in the middle of the slabs both parallel (longitudinal) and orthogonal (transverse) to the prestressing direction. More pronounced curvature in the transverse direction is accompanied by the formation of cracks running predominantly in the longitudinal direction. While the transverse curvature relaxes back to the original state after the cooling phase the curvature in the longitudinal direction ultimately exhibits upward deflection due to the hogging moment caused by the prestress in the tendons acting on a cross section with temperature reduced mechanical properties at the fire exposed side. The effect on crack formation due to the prestressing can additionally be detected by ultrasonic pulse velocity measurements in the different directions through the depth of the slab, where a reduction of 5–25% is observed in the transverse direction compared to the longitudinal direction. The phenomenological mechanical behaviour of the slabs is captured in a finite element model which describes the evolution of stress in the prestressing tendons. This model additionally suggests that the curvature in the transverse direction is independent of the prestressing in the longitudinal direction.

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References

  1. Huang ZH, Burgess IW, Plank RJ (2003) Modeling membrane action of concrete slabs in composite buildings in fire. I: theoretical development. J Struct Eng– ASCE. 129(8): 1093–1102.

    Article  Google Scholar 

  2. Fédération Internationale du béton (2008) “Fire design of concrete structures—structural behaviour and assessment” State of the art report, Bulletin 46.

  3. Hertz KD (2003) Limits of spalling of fire-exposed concrete. Fire Saf J 38(2): 103–116.

    Article  Google Scholar 

  4. Jansson R, Boström l (2013) Factors influencing fire spalling of self compacting concrete. Mater Struct 46(10): 1683–1694.

    Article  Google Scholar 

  5. Bailey CG, Ellobody E. (2009) Comparison of unbonded and bonded post-tensioned concrete slabs under fire conditions. Structural Engineer 87(19): 23–31.

    Google Scholar 

  6. Gales J, Hartin K, Bisby L.(2016) Structural fire performance of contemporary post-tensioned concrete construction. Springer, London.

    Book  Google Scholar 

  7. Kalifa P, Chene G, Galle C. (2001) High-temperature behaviour of HPC with polypropylene fibres - from spalling to microstructure Cem Concr Res 31(10): 1487–1499.

    Article  Google Scholar 

  8. Gales J, Bisby L, Gillie M. (2011) Unbonded post tensioned concrete slabs in fire - part II - modelling tendon response and the consequences of localized heating. J of Struct Fire Eng 2(3): 155–171.

    Article  Google Scholar 

  9. Gales J, Parker T, Cree D, Green M, et al (2016) Fire performance of sustainable recycled concrete aggregates: mechanical properties at elevated temperatures and current research needs Fire Technol 52: 817–845.

    Article  Google Scholar 

  10. Zheng W, Hou X (2008) Experiment and analysis on the mechanical behaviour of PC simply supported slabs subjected to fire. Adv Struct Eng 11(1): 71–89.

    Article  Google Scholar 

  11. Bailey CG, Ellobody E.(2009) Fire tests on unbonded post-tensioned one-way concrete slabs. Mag Conc Res 61(1): 67–76.

    Article  Google Scholar 

  12. Yang JC, et al. (2015) International R&D Roadmap for Fire Resistance of Structures Summary of NIST/CIB Workshop, NIST Special Publication 1188, National Institute of Standards and Technology.

  13. Ellobody E, Bailey C. G. (2008) Testing and modelling of bonded and unbonded post-tensioned concrete slabs in fire. Proceedings of the 5th International Conference on Structures in Fire (SiF’08), pp 392-405.

  14. Ellobody E, Bailey CG, (2009) Modelling of unbonded post-tensioned concrete slabs under fire conditions. Fire Saf J 44(2): 159–167.

    Article  Google Scholar 

  15. Ellobody E, Bailey CG (2011) Structural performance of a post-tensioned concrete floor during horizontally travelling fires Eng Struct 33(6): 1908–1917.

    Article  Google Scholar 

  16. Stern-Gottfried J, Rein G (2012) Travelling fires for structural design-Part II: design methodology Fire Saf J 54: 96–112.

    Article  Google Scholar 

  17. Cooke GME (2001) Behaviour of precast concrete floor slabs exposed to standardised fires Fire Saf J 36(5): 459–475.

    Article  Google Scholar 

  18. Anderberg Y (1976) Fire-exposed hyperstatic concrete structures—an experimental and theoretical study PhD Thesis, Lund Institute of Technology, Lund.

  19. Naik TR, Malhorta VM, Popovics JS.et al. (2004) The ultrasonic pulse velocity method. In: Malhorta VM, Carino NJ, (eds.) Handbook on nondestructive testing of concrete, 2nd edn. CRC Press, London.

    Google Scholar 

  20. Sjöström J, Jansson R, Lange D, Boström L et al (2012) Directional dependence of deflections and damages during fire tests of post-tensioned concrete slabs, Proceedings of the 7th International Conference on Structures in Fire, Zürich.

  21. Lange D, Sjöström J, Jansson R, Boström L. (2012) Deflection of concrete floor slab during a fire test: tests and modelling, Proceedings of ICEM15, Porto.

  22. Malhotra HL (1957) The effect of temperature on the compressive strength of concrete, Mag Concr Res 23: 1957.

    Google Scholar 

  23. Dassault Systémes Simulia Corp (2011) “ABAQUS 6.11.”.

  24. Law A, (2010) The assessment and response of concrete structures subject to fire, PhD Thesis, The University of Edinburgh.

  25. CEN, European Committee for Standardization (2002) EN 1991-1-2:2002 Eurocode 1: Actions on structures—Part 1-2: Actions on structures exposed to fire. Brussels.

  26. CEN, European Committee for Standardization (2004) EN 1992-1-2:2004 Eurocode 2: Design of concrete structures—Part 1-2: General rules—Structural fire design. Brussels.

  27. CEN, European Committee for Standardization (2005) EN 1993-1-2:2005 Eurocode 3: Design of steel structures—Part 1-2: Structural fire design. Brussels.

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    Authors and Affiliations

    1. SP Technical Research Institute of Sweden, Box 857, 501 15, Borås, Sweden

      Johan Sjöström, David Lange, Robert Jansson McNamee & Lars Boström

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    1. Johan Sjöström
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    2. David Lange
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    3. Robert Jansson McNamee
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    4. Lars Boström
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    Correspondence to Johan Sjöström.

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    Johan Sjöström and David Lange have contributed equally to this work.

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    Sjöström, J., Lange, D., Jansson McNamee, R. et al. Anisotropic Curvature and Damage of Unbonded Post-tensioned Concrete Slabs During Fire Testing. Fire Technol 53, 1333–1351 (2017). https://doi.org/10.1007/s10694-016-0637-8

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    • DOI: https://doi.org/10.1007/s10694-016-0637-8

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