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Shrinkage movement analysis of reinforced concrete floors constructed in stages

  • Kwan, A.K.H. (Department of Civil Engineering The University of Hong Kong) ;
  • Ng, P.L. (Department of Civil Engineering The University of Hong Kong)
  • Received : 2007.11.28
  • Accepted : 2009.03.31
  • Published : 2009.04.25

Abstract

Reinforced concrete floors constructed between movement restraints often crack seriously due to shrinkage after completion. One common mitigation measure is to construct the concrete floors in stages to allow part of the shrinkage movement to take place before completion. However, shrinkage movement analysis of concrete floors constructed in stages is quite cumbersome, as the structural configuration changes during construction, thus necessitating reanalysis of the partially completed structure at each stage. Herein, a finite element method for shrinkage movement analysis of concrete floors constructed in stages is developed. It analyses the whole structure, including the completed and uncompleted portions, at all stages. The same mesh is used all the time and therefore re-meshing and location matching are no longer necessary. This is achieved by giving negligibly small stiffness to the uncompleted portions, which in reality do not exist yet. In the analysis, the locked-in strains due to increase in elastic modulus as the concrete hardens and the creep of the hardened concrete are taken into account. Most important of all, this method would enable fully automatic shrinkage movement analysis for the purpose of construction control.

Keywords

References

  1. Anderson, C.A. (1982), "Numerical creep analysis of structures", Creep and Shrinkage in Concrete Structures, edited by Bazant, Z.P. and Wittmann, F.H., John Wiley and Sons, New York, USA, 259-303.
  2. Au, F.T.K., Liu, C.H. and Lee, P.K.K. (2007), "Shrinkage analysis of reinforced concrete floors using shrinkage-adjusted elasticity modulus", Comp. Concrete, 4(6), 437-456. https://doi.org/10.12989/cac.2007.4.6.437
  3. British Standards Institution, BS5400: Part 4 Code of Practice for Design of Concrete Bridges, British Standards Institution, UK, 1990.
  4. Comite Euro-International du Beton, CEB-FIP Model Code 1990: Model Code for Concrete Structures, Thomas Telford Services Ltd., London, UK, 1993.
  5. Ghali, A., Favre, R. and Elbadry, M. (2002), Concrete Structures: Stresses and Deformation, Third Edition, Spon Press, London, UK, 584.
  6. Gilbert, R.I. (1988), Time Effects in Concrete Structures, Elsevier Science Publishers B.V., Amsterdam, The Netherlands, 321.
  7. Gilbert, R.I. (1992), "Shrinkage cracking in fully restrained concrete members", ACI Struct. J. 89(2), 141-149.
  8. Han, D.J. and Yan, Q.S. (2003), "Cable force adjustment and construction control", Chapter 7, Bridge Engineering: Construction and Maintenance, Edited by Chen, W.F. and Duan, L., CRC Press, USA, 22.
  9. Jurkiewiez, B., Destrebecq, J.F. and Vergne, A. (1999), "Incremental analysis of time-dependent effects in composite structures", Comp. Struct., 73(1-5), 425-435. https://doi.org/10.1016/S0045-7949(98)00269-7
  10. Kim, H.S. and Cho, S.H. (2004), "Shrinkage stress analysis of concrete slabs with shrinkage strips in a multistory building", Comp. Struct., 82(15-16), 1143-1152. https://doi.org/10.1016/j.compstruc.2004.03.021
  11. Kim, H.S. and Cho, S.H. (2005), "Shrinkage stress analysis of concrete slab in multistorey building considering variation of restraint and stress relaxation due to creep", Struct. Des. Tall Special Build., 14(1), 47-58. https://doi.org/10.1002/tal.258
  12. Kwan, A.K.H., Au, F.T.K. and Lee, P.K.K. (2002), "Minimizing shrinkage cracks in concrete structures for better serviceability and durability", Proceedings, Innovative Buildings Symposium, Hong Kong, 117-136.
  13. Kwan, A.K.H., Au, F.T.K. and Lee, P.K.K. (2003), "High-performance concrete buildings for the new millennium", Prog. Struct. Eng. Mater., 5(4), 263-273. https://doi.org/10.1002/pse.158
  14. Liu, C.H., Au, F.T.K. and Lee, P.K.K. (2006), "Estimation of shrinkage effects on reinforced concrete podiums", HKIE Transactions, 13(4), 33-43.
  15. McHenry, D. (1943), "A new aspect of creep in concrete and its application to design", ASTM Proceedings, 43, 1069-1084.
  16. Nejadi, S. and Gilbert, I. (2004), "Shrinkage cracking and crack control in restrained reinforced concrete members", ACI Struct. J., 101(6), 840-845.
  17. Neville, A.M. (1995), Properties of Concrete, Fourth Edition, Addison Wesley Longman Ltd., London, UK, 844.
  18. Ng, P.L., Lam, J.Y.K. and Kwan, A.K.H. (2007), "Multi-layer visco-elastic creep model for time-dependent analysis of concrete structures", Proceedings, Eleventh International Conference on Civil, Structural and Environmental Engineering Computing, St. Julians, Malta, Edited by Topping, B.H.V., 17. (published in CD-ROM).

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