Title:
Evaluation of Effective Moment of Inertia for Calculation of Short-Term Deflections of Steel Fiber Reinforced Concrete Flexural Members
Author(s):
Fargier-Gabaldon, L.B.; Al-Tameemi, M.; Parra-Montesinos, G.J.
Publication:
Symposium Paper
Volume:
343
Issue:
Appears on pages(s):
411-420
Keywords:
Fiber Reinforced Concrete, Effective Moment of Inertia, Short-Term Deflections, Tension- Stiffening.
DOI:
Date:
10/1/2020
Abstract:
The effect of discontinued, randomly distributed steel fibers on the effective moment of inertia (𝐼!) of lightly reinforced flexural members is evaluated through the testing of three pairs of specimens under four-point bending. The specimens consisted of a simply supported, 3660 mm long, 254 mm deep, and 610 mm wide one-way slab strip. All slab specimens contained minimum flexural reinforcement according to the ACI 318-14 Building Code. The first pair featured regular concrete (no fibers), while the second and third pairs included steel fibers in a volume fraction (𝑉") of 0.26% and 0.38%, respectively. Beyond cracking, a substantial drop in
the flexural stiffness was noticed in all specimens. The slabs with fibers, however, exhibited stiffer post-cracking response compared to their regular concrete counterparts. At yielding, a well-distributed cracking pattern was noticed in all test slabs, with maximum cracks widths of approximately 0.5 mm. It was found that the equation proposed by Bischoff (2005) to estimate the effective moment of inertia for concrete beams fits well the experimental data of the fiberreinforced concrete slabs, given that the stiffening factor is set equal to one.
Related References:
ACI Committee 318. “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, Michigan, 2014, 520 pp.
Parra-Montesinos, G. 2006. “Shear Strength of Beams with Deformed Steel Fibers,” Concrete International, V. 28, No. 11, pp. 57 -66.
Kang, T., Kim, W., Kwak, Y. and Hong, S. 2011. “Shear Testing of Steel Fiber-Reinforced Lightweight Concrete Beams without Web Reinforcement,” ACI Structural Journal, V. 108, No. 5, pp. 553-561.
Ashour, S. A. and Wafa, F. F. 1993. “Flexura Behavior of High-Strength Fiber-Reinforced Concrete Beams,” ACI Structural Journal, V. 90, No. 3, pp. 279-287.
Kang, T., Kim, W., Massone, L. and Galleguillos, T. 2012. “Shear-Flexure Coupling Behavior of Steel Fiber-Reinforced Concrete Beams,” ACI Structural Journal, V. 109, No. 4, pp. 435-444.
Sahoo, D. and Sharma, A. 2014. “Effect of Steel Fiber Content on Behavior of Concrete Beams with and without Stirrups,” ACI Structural Journal, V. 111, No. 5, pp. 1157-1166.
Meda, A., Minelli, F., and Plizzari, G.A. (2012), “Flexural behaviour of RC beams in fibre reinforced concrete”, Composites Part B: Engineering, Vol. 43, No 8, December 2012, ISSN 1359-8368, pp. 2930 -2937.
Branson, D. 1965. “Instantaneous and Time-Dependent Deflections of Simple and Continuous Reinforced Concrete Beams,” APR Rep. No. 7, Part I, Alabama Highway Dept., Bureau of Public Roads.
ACI Committee 318. “Building Code Requirements for Reinforced Concrete and Commentary (ACI 318-89),” American Concrete Institute, Farmington Hills, Michigan, 1989, 353 pp.
ACI Committee 318. “Building Code Requirements for Reinforced Concrete (ACI 318-71),” American Concrete Institute, Farmington Hills, Michigan, 1971, 78 pp.
Bischoff, P. 2005. “Reevaluation of Deflection Prediction for Concrete Beams Reinforced with Steel and Fiber Reinforced Polymer Bars,” Journal of Structural Engineering, ASCE, V. 131, No. 5, pp. 752-767.
Bischoff, P. and Scanlon, A. 2007. “Effective Moment of Inertia for Calculating Deflections of Concrete Members Containing Steel Reinforcement and FRP Reinforcement,” ACI Structural Journal, V. 104, No. 1, pp. 68-75.