Finite Element Modelling of Post-tensioned Timber Beams at Ambient and Fire Conditions

Abstract

An increased environmental conscientiousness in society and the abundance of timber in Canada has inevitably led to the desire for more timber construction. In order to increase the opportunity for timber products in construction, novel building systems such as post-tensioned (PT) timber have been developed. Limited development on numerical modelling has been done on PT timber systems for the optimization of design for fire performance. In industry, there is need for a modelling software capable of approximating complex timber system behaviours that is accessible to practitioners. This research program serves to evaluate the current capabilities or shortcomings of modelling PT timber in both ambient and fire conditions, and to develop a methodology for analyzing the performance of the system. Several numerical models of PT timber beam tests are developed and validated using general purpose FEM software ABAQUS. This software is a good research tool and the lessons learned may be used to refine an accessible model for practitioners. Various material definitions are compared including isotropic and orthotropic models. The numerical models show highly promising results for demonstrating the loading and failure behaviour of PT timber beams. Material property directionality is paramount, captured best with the use of Hill’s Potential Function for non-elastic behaviour. Ambient beam tests are modelled with accurately demonstrated load–deflection behaviour and peak loads are computed to within 5% of experimentally recorded values. For PT timber beam standard fire furnace tests, beam failure times are modelled within 3 min of experimental beam failure times for various fire exposure durations (about 5%), and load–deflection behaviour and failure mechanisms are accurately demonstrated. Thermal gradients align with the recorded thermocouple readings and char depths are computed within 4 mm of the observed layers.

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References

  1. 1.

    Pilon A et al (2017) Brock commons Tallwood house: construction overview. University of British Columbia’s Centre for interactive research on sustainability, Naturally: Wood, BC. http://wood-works.ca/wp-content/uploads/brock_commons_-_construction_overview.pdf

  2. 2.

    CTBUH (Council on Tall Buildings and Urban Habitat) (2017) Tall timber: a global audit, in tall buildings in numbers. CTBUH J, (II)47–49. http://global.ctbuh.org/resources/papers/3350-TBIN.pdf

  3. 3.

    Palermo A, Pampanin S, Buchanan A, Newcombe M (2005) Seismic design of multi-storey buildings using Laminated Veneer Lumber (LVL). In: Proceedings of the New Zealand society for earthquake engineering conference, paper 14

  4. 4.

    Spellman PM (2012) The fire performance of post-tensioned timber beams. University of Canterbury, Christchurch

    Google Scholar 

  5. 5.

    Costello RS (2013) The fire performance of post-tensioned timber buildings. University of Canterbury, Christchurch

    Google Scholar 

  6. 6.

    Law A (2016) The role of modelling in structural fire engineering design. Fire Saf J 80:89–94. https://doi.org/10.1016/j.firesaf.2015.11.013

    Article  Google Scholar 

  7. 7.

    Buchanan A, Palermo A, Carradine DM, Pampanin S (2011) Post-tensioned timber frame buildings. Struct Eng 89(17):24–30

    Google Scholar 

  8. 8.

    Granello G, Leyder C, Frangi A, Palermo A, Chatzi E (2019) Long-term performance assessment of an operative post-tensioned timber frame structure. J Struct Eng 145(5):04019034

    Article  Google Scholar 

  9. 9.

    Wanninger F, Frangi A (2014) Experimental and analytical analysis of a post-tensioned timber connection under gravity loads. Eng Struct 70:117–129. https://doi.org/10.1016/j.engstruct.2014.03.042

    Article  Google Scholar 

  10. 10.

    Van Beerschoten WA (2013). Structural performance of post-tensioned timber frames under gravity loading. University of Canterbury, Christchurch

    Google Scholar 

  11. 11.

    ISO (International Organization for Standardization) (2014) ISO 834-10. fire resistance tests: elements of building construction. International Organization for Standardization, Geneva

    Google Scholar 

  12. 12.

    Nelson Pine Industries Limited (2016) Laminated veneer lumber: specific engineering design guide. http://www.nelsonpine.co.nz/wp-content/uploads/LVL_Specific_Engineering_Design_Guide.pdf

  13. 13.

    Fredlund B (1993) modelling of heat and mass transfer in wood structures during fire. Fire Saf J 20:39–69

    Article  Google Scholar 

  14. 14.

    Richter F, Rein G (2018) The role of chemistry in predicting the charring rates under realistic fire conditions. In: 12th international performance-based codes and fire safety design methods, Honolulu, USA

  15. 15.

    König J (2005) Structural fire design according to Eurocode 5—design rules and their background. Fire Mater 29:147–163. https://doi.org/10.1002/fam.873

    Article  Google Scholar 

  16. 16.

    CEN (European Committee for Standardization) (2004) Annex B: (informative) advanced calculation methods, part 1–2: general—structural fire design, Eurocode 5: design of timber structures. british standards institute, London, pp 20–28

    Google Scholar 

  17. 17.

    Werther N, O’Neill JW, Spellman PM, Abu AK, Moss PJ, Buchanan AH, Winter S (2012) Parametric study of modelling structural timber in fire with different software packages. In: Proceedings of the 7th international conference on structures in fire, pp 427–436

  18. 18.

    Menis A (2012) Fire resistance of Laminated Veneer Lumber (LVL) and Cross-Laminated Timber (XLAM) elements. Università Degli Studi di Cagliari, Cagliari

    Google Scholar 

  19. 19.

    Dassault Systèmes (2012) Section 27.1.1 element library: overview in ABAQUS analysis user’s guide, ABAQUS 6.14. Dassault Systèmes Simulia Corp., Providence, RI

  20. 20.

    CEN (European Committee for Standardization) (2004) Section 3.4: thermal elongation of reinforcing and prestressing steel, part 1–2: general rules—structural fire design, Eurocode 2: design of concrete structures. British Standards Institute, London, pp. 28–29

  21. 21.

    Drysdale DD (2016) Heats of combustion, Section 5—thermochemistry. In: Hurley MJ (ed), SFPE handbook of fire protection 5th edition. Society of Fire Protection Engineers, Springer, Berlin, pp 138–150. https://doi.org/10.1007/978-1-4939-2565-0_5

    Google Scholar 

  22. 22.

    CEN (European Committee for Standardization) (2004) Section 3 thermal actions for temperature analysis, part 1–2: general rules—actions on structures exposed to fire, Eurocode 1: actions on structures. British Standards Institute, London, pp 23–24

    Google Scholar 

  23. 23.

    Chen Z, Zhu E, Pan J (2011) Numerical simulation of mechanical behaviour of wood under complex stress. Chin J Comput Mech 28(4), pp 629–634 +640.

    Google Scholar 

  24. 24.

    Zhang J, Wang Y, Li L, Xu Q (2017) Thermo-mechanical behaviour of dovetail timber joints under fire exposure. Fire Saf J. https://doi.org/10.1016/j.firesaf.2017.11.008

    Article  Google Scholar 

  25. 25.

    Yamada S, Sun C (1978) Analysis of laminate strength and its distribution. J Compos Mater 12(3):275–284. https://doi.org/10.1177/002199837801200305

    Article  Google Scholar 

  26. 26.

    Ardalany M, Deam B, Fragiacomo M, Crews KI (2011) Tension perpendicular to grain strength of wood, Laminated Veneer Lumber (LVL), and cross-banded LVL (LVL-C). In: Proceedings of the 21st Australasian conference on the mechanics of structures and materials, pp 891–896

    Google Scholar 

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Acknowledgements

NSERC Discovery Grant RGPIN-2015-05081, the NSERC CGS and the NSERC Michael Smith Foreign Study Supplement program made this research possible.

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Correspondence to John Gales.

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Quiquero, H., Gales, J., Abu, A. et al. Finite Element Modelling of Post-tensioned Timber Beams at Ambient and Fire Conditions. Fire Technol 56, 737–767 (2020). https://doi.org/10.1007/s10694-019-00901-0

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Keywords

  • Post-tensioned timber
  • Finite element method
  • Numerical model
  • Engineered timber
  • ABAQUS