DOI QR코드

DOI QR Code

Effect of fiber reinforcing on instantaneous deflection of self-compacting concrete one-way slabs under early-age loading

  • Vakhshouri, Behnam (Faculty of Engineering and Information Technology, School of Civil and Environmental Engineering, University of Technology Sydney) ;
  • Nejadi, Shami (Faculty of Engineering and Information Technology, School of Civil and Environmental Engineering, University of Technology Sydney)
  • Received : 2017.01.07
  • Accepted : 2018.05.04
  • Published : 2018.07.25

Abstract

The Early-age construction loading and changing properties of concrete, especially in the multi-story structures can affect the slab deflection, significantly. Based on previously conducted experiment on eight simply-supported one-way slabs this paper investigates the effect of concrete type, fiber type and content, loading value, cracking moment, ultimate moment and applied moment on the instantaneous deflection of Self-Compacting Concrete (SCC) slabs. Two distinct loading levels equal to 30% and 40% of the ultimate capacity of the slab section were applied on the slabs at the age of 14 days. A wide range of the existing models of the effective moment of inertia which are mainly developed for conventional concrete elements, were investigated. Comparison of the experimental deflection values with predictions of the existing models shows considerable differences between the recorded and estimated instantaneous deflection of SCC slabs. Calculated elastic deflection of slabs at the ages of 14 and 28 days were also compared with the experimental deflection of slabs. Based on sensitivity analysis of the effective parameters, a new model is proposed and verified to predict the effective moment of inertia in SCC slabs with and without fiber reinforcing under two different loading levels at the age of 14 days.

Keywords

References

  1. Achintha, P.M. and Burgoyne, C.J. (2009), "Moment-curvature and strain energy of beams with external fiber-reinforced polymer reinforcement", ACI Struct. J., 106(1), 20-29.
  2. ACI-318-08 (2008), Building Code Requirements for Structural Concrete ACI-318-08, American Concrete Institute, Farmington Hills, Michigan, U.S.A.
  3. Alsayed, S., Al-Salloum, Y. and Almusallam, T. (2000), "Performance of glass fiber reinforced plastic bars as a reinforcing material for concrete structures", Compos. Part B: Eng., 31(6), 555-567. https://doi.org/10.1016/S1359-8368(99)00049-9
  4. Alshaikh, A.H. and Al-Zaid, R. (1993), "Effect of reinforcement ratio on the effective moment of inertia of reinforced concrete beams", Struct. J., 90(2), 144-149.
  5. Aslani, F. and Nejadi, S. (2012), "Mechanical properties of conventional and self-compacting concrete: An analytical study", Constr. Build. Mater., 36, 330-347. https://doi.org/10.1016/j.conbuildmat.2012.04.034
  6. Aslani, F., Nejadi, S. and Samali, B. (2014), "Long-term flexural cracking control of reinforced self-compacting concrete one way slabs with and without fibres", Comput. Concrete, 14(4), 419-443. https://doi.org/10.12989/cac.2014.14.4.419
  7. Benmokrane, B., Chaallal, O. and Masmoudi, R. (1996), "Flexural response of concrete beams reinforced with FRP reinforcing bars", ACI Struct. J., 93(1), 46-55.
  8. Bischoff, P.H. and Gross, S.P. (2010), "Equivalent moment of inertia based on integration of curvature", J. Compos. Constr., 15(3), 263-273. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000164
  9. Darwin, D., Scanlon, A., Gergely, P., Bishara, A.G., Boggs, H.L., Brander, M.E., Carlson, R.W., Clark Jr, W.L., Fouad, F.H. and Polvika, M. (1986), "Cracking of concrete members in direct tension", ACI J. Proc.
  10. EUROCODE, N. (1994), 8: Design Provisions for Earthquake Resistance of Structures, Part 2: 1998-1992.
  11. Faza, S. and GangaRao, H. (1992), "Pre-and post-cracking deflection behaviour of concrete beams reinforced with fibrereinforced plastic rebars", Proceedings of the 1st International Conference on Advance Composite Materials in Bridges and Structures (ACMBS-I), Canadian Society of Civil Engineers, Sherbrooke, Cananda.
  12. Fikry, A.M. and Thomas, C. (1998), "Development of a model for the effective moment of inertia of one-way reinforced concrete elements", Struct. J., 95(4), 445-455.
  13. Gilbert, I.R. (2007), "Tension stiffening in lightly reinforced concrete slabs", J. Struct. Eng., 133(6), 899-903. https://doi.org/10.1061/(ASCE)0733-9445(2007)133:6(899)
  14. Hall, T. and Ghali, A. (2000), "Long-term deflection prediction of concrete members reinforced with glass fibre reinforced polymer bars", Can. J. Civil Eng., 27(5), 890-898. https://doi.org/10.1139/l00-009
  15. Lee, J., Scanlon, A. and Scanlon, M. (2007), "Effect of early age loading on time-dependent deflection and shrinkage restraint cracking of slabs with low reinforcement ratios", Spec. Publ., 246, 149-166.
  16. Mazzotti, C. and Savoia, M. (2009), "Long-term deflection of reinforced self-consolidating concrete beams", ACI Struct. J., 106(6), 772.
  17. Newhook, J. (2001), Reinforcing Concrete Structures with Fibre Reinforced Polymers, T. C. N. o. C. o. e. o. i. s. f. i. Structures, Manitoba, Canada, ISIS Canada: Design Manual No.3, 3.
  18. Park, H., Hwang, H., Kim, J., Hong, G., Im, J. and Kim, Y. (2010), "Creep and effective stiffness of early age concrete slabs", Proceeding of the Fracture Mechanics of Concrete and Concrete Structures-Assessment, Durability, Monitoring and Retrofitting of Concrete Structures, Jeju, South Korea.
  19. Rafi, M.M., Nadjai, A., Ali, F. and Talamona, D. (2008), "Aspects of behaviour of CFRP reinforced concrete beams in bending", Constr. Build. Mater., 22(3), 277-285. https://doi.org/10.1016/j.conbuildmat.2006.08.014
  20. Scanlon, A. and Bischoff, P.H. (2008), "Shrinkage restraint and loading history effects on deflections of flexural members", ACI Struct. J., 105(4), 498.
  21. Standards, A. (2009), Concrete Structures, AS-3600-09, Standards Australia, Australia.
  22. Sukumar, B., Nagamani, K. and Raghavan, R.S. (2008), "Evaluation of strength at early ages of self-compacting concrete with high volume fly ash", Constr. Build. Mater., 22(7), 1394-1401. https://doi.org/10.1016/j.conbuildmat.2007.04.005
  23. Vakhshouri, B. (2016), "Time-dependent bond transfer length under pure tension in one way slabs", Struct. Eng. Mech., 60(2), 301-312. https://doi.org/10.12989/sem.2016.60.2.301
  24. Vakhshouri, B. and Nejadi, S. (2014), Limitations and Uncertainties in the Long-Term Deflection Calculation of Concrete Structures. Vulnerability, Uncertainty, and Risk: Quantification, Mitigation, and Management, ASCE.
  25. Yost, J.R., Gross, S.P. and Dinehart, D.W. (2003), "Effective moment of inertia for glass fiber-reinforced polymer-reinforced concrete beams", Struct. J., 100(6), 732-739.