Structural Engineering and Mechanics

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Modelling of bonded and unbonded post-tensioned concrete flat slabs under flexural and thermal loading

  • Mohammed, Abbas H. (Department of Civil Engineering, Gaziantep University) ;
  • Taysi, Nildem (Department of Civil Engineering, Gaziantep University)
  • Received : 2015.05.29
  • Accepted : 2017.05.11
  • Published : 2017.06.10
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Abstract

During their life span, post-tensioned concrete structures may be exposed to thermal loads. Therefore, there has been a growing interest in research on the advanced analysis and design of post-tensioned concrete slabs subjected to thermal loads. This paper investigates the structural behaviour of post-tensioned one-way spanning concrete slabs. A nonlinear finite element model for the analysis of post- tensioned unbonded and bonded concrete slabs at elevated temperatures was developed. The interface between the tendon and surrounding concrete was also modelled, allowing the tendon to retain its profile shape during the deformation of the slab. The load-deflection behaviour, load-force behaviour in the tendon, and the failure modes are presented. The numerical analysis was conducted by the finite element ANSYS software and was carried out on two different one-way concrete slabs chosen from literature. A parametric study was conducted to investigate the effect of several selected parameters on the overall behavior of post-tensioned one-way concrete slab. These parameters include the effect of tendon bonding, the effect of thermal loading and the effect of tendon profile. Comparison between uniform thermal loading and nonuniform thermal loading showed that restrained post tensioned slab with bottom surface hotter has smaller failure load capacity.

Keywords

References

  1. ANSYS (2012), ANSYS Help, Release 14.5, Copyright.
  2. Bailey, C.G. and Ellobody, E. (2009a), "Fire tests on unbonded post-tensioned one-way concrete slabs", Magaz. Concrete Res., 61(1), 67-76 https://doi.org/10.1680/macr.2008.00005
  3. Bailey, C.G. and Ellobody, E. (2009b), "Fire tests on bonded posttensioned concrete slabs", Eng. Struct., 31(3), 686-696. https://doi.org/10.1016/j.engstruct.2008.11.009
  4. Ellobody, E. and Bailey, C.G. (2009), "Modelling of unbonded post-tensioned concrete slabs under fire conditions", Fire Safe. J., 44(2), 159-167. https://doi.org/10.1016/j.firesaf.2008.05.007
  5. European Committee for Standardization (CEB), Eurocode 3, (1993), Design of Steel Structures. Part 1.1: General Rules and Rules for Buildings, DD ENV, 1-1, EC3.
  6. Desayi, P. and Krishnan, S. (1964), "Equation for the stress-strain curve of concrete", J. Am. Concrete Inst., 61(3), 345-350.
  7. Fanning, P. (2001), "Nonlinear models of reinforced and posttensioned concrete beams", Electronic J. Struct. Eng., 2, 111-119.
  8. Kang, T. and Huang, Y. (2012), "Computer Modeling of Post-Tensioned Structures", 4th International Conference on Computer Modeling and Simulation (ICCMS 2012), Singapore.
  9. Kasat, A.S. and Varghese, V. (2012), "Finite element analysis of prestressed concrete beams", Int. J. Adv. Technol. Civ. Eng., 1(3, 4), 2231-5721.
  10. Kim, K.S. and Lee, D.H. (2012), "Nonlinear analysis method for continuous post-tensioned concrete members with unbonded tendons", Eng. Struct., 40, 487-500. https://doi.org/10.1016/j.engstruct.2012.03.021
  11. Ranzi, G., Al-Deen, S., Ambrogi, L. and Uym, B. (2013), "Longterm behaviour of simply-supported post-tensioned composite slabs", J. Constr. Steel Res., 88, 172-180. https://doi.org/10.1016/j.jcsr.2013.05.010
  12. Williams, M.S. and Waldron, P. (1989), "Movement of unbonded post-tensioning tendons during demolition", Proceedings of the Institution of Civil Engineers, Part 2, 87, 225-253. https://doi.org/10.1680/iicep.1989.2005
  13. Yang, K.H., Mun, J.H. and Kim, G.H. (2013), "Flexural behavior of post-tensioned normal-strength lightweight concrete one-way slabs", Eng. Struct., 56, 1295-1307. https://doi.org/10.1016/j.engstruct.2013.07.004

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