Structural Engineering and Mechanics

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Long-term deflection of high-strength fiber reinforced concrete beams

  • Ashour, Samir A. (Civil Engineering Department, King Abdulaziz University) ;
  • Mahmood, Khalid (Civil Engineering Department, King Abdulaziz University) ;
  • Wafa, Faisal F. (Civil Engineering Department, King Abdulaziz University)
  • Published : 1999.12.25
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Abstract

The paper presents an experimental and theoretical study on the influence of steel fibers and longitudinal tension and compression reinforcements on immediate and long-term deflections of high-strength concrete beams of 85 MPa (12,300 psi) compressive, strength. Test results of eighteen beams subjected to sustained load for 180 days show that the deflection behavior depends on the longitudinal tension and compression reinforcement ratios and fiber content; excessive amount of compression reinforcement and fibers may have an unfavorable effect on the long-term deflections. The beams having the ACI Code's minimum longitudinal tension reinforcement showed much higher time-dependent deflection to immediate deflection ratio, when compared with that of the beams having about 50 percent of the balanced tension reinforcement. The results of theoretical analysis of tested beams and those of a parametric study show that the influence of steel fibers in increasing the moment of inertia of cracked transformed sections is most pronounced in beams having small amount of longitudinal tension reinforcement.

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References

  1. ACI Committee 318 (1989), "Building Code requirements for reinforced concrete (ACI 318-89)", American Concrete Institutes, Detroit, 353.
  2. ACI Committee 318 (1995), "Building Code requirements for reinforced concrete (ACI 318-95)", American Concrete Institutes, Detroit, 369.
  3. ACI Committee 363 (1992), "State of the art report on high-strength concrete", American Concrete Institutes, Detroit, 55.
  4. ACI Committee 435 (1990), "Deflections of reinforced concrete flexural members", ACI 435.2R 66 (Reapproved 1989), Manual of Concrete Practice, Part 4, American Concrete Institute, Detroit, 1-29.
  5. Alsayed, S.H. (1993), "Flexural deflection of reinforced fibrous concrete beams", ACI Structural Journal, 90(1), 72-76.
  6. Ashour, S.A., Mahmood, K. and Wafa, F.F. (1997), "Influence of steel fibers and compression reinforcement on deflection of high-strength concrete beams" , ACI Structural Journal, 94(6), 611- 624.
  7. Bakoss, S.L., Gilbert, R.I., Faulkes, K.A. and Pulmano, V.A. (1982), "Long-term deflections of reinforced concrete beams", Magazine of Concrete Research, London, 34(121), 203-212. https://doi.org/10.1680/macr.1982.34.121.203
  8. Corley, W.G. and Sozen, M.A. (1966), "Time-dependent deflections of reinforced concrete beams" , ACI Journal, 63(3), 373-386.
  9. Lim, T.Y., Paramasivan, P. and Lee, S.L. (1987), "Behavior of reinforced steel fiber concrete beams in flexure" , Journal of Structural Engineering, ASCE, 113(ST 12), 2439-2458. https://doi.org/10.1061/(ASCE)0733-9445(1987)113:12(2439)
  10. Patton, M.E. and Whittaker, W.L. (1990), "Effect of fiber content and damaging load of steel fiber reinforced concrete stiffness" , ACI Journal, Proceeding 80(1), 13-16.
  11. Paulson, K.A., Nilson, A.H. and Hover, K.C. (1991), "Long-term deflection of high-strength concrete beams" , ACI Materials Journal, 88(5), 197-206.
  12. Soroushian, P. and Lee, C. (1990), "Distribution and orientation of fibers in steel fiber reinforced concrete" , ACI Materials Journal, 87(5), 433-439.
  13. Swamy, R.N. and Al-Ta'an, S.A. (1981), "Deformation and ultimate strength in flexure of reinforced concrete beams made with steel fiber concrete" , ACI Journal, Proceedings, 78(5), 395-405.
  14. Washa, G.W. and Fluck, P.G. (1952), "Effect of compression reinforcement on the plastic flow or reinforced concrete beams" , ACI Journal, 49(2), 89-108.
  15. Yu W.W. and Winter, G. (1960), "Instantaneous and long-time deflections of reinforced concrete beams under working loads" , ACI Journal, 57(1), 29-50.

Cited by

  1. Systematic Review on the Creep of Fiber-Reinforced Concrete vol.13, pp.22, 1999, https://doi.org/10.3390/ma13225098