ACI 544.6R-2015 Report on Design and Construction of Steel Fiber-Reinforced Concrete Elevated Slabs.
3.2—Advantages of G-SFRC and E-SFRC slab systems There are numerous advantages of using the SFRC systems that make them sustainable products. These are defned in terms of several categories, including speed of construction, strength, ductility, shrinkage control in terms of crack width control, and long-term durability that ultimately leads to an economic and sustainable design. 3.2.1 Economic advantages—A key economic advantage is the reduction in construction time compared with the traditional installation of double layers of conventional reinforcing bars, stirrups, or other shear reinforcement. Time savings of several weeks for G-SFRC slab projects larger than 110,000 ft 2 (10,000 m 2 ) can be obtained; however, the economic costs and actual savings are based on a collection of individual gains obtained and measured using appropriate construction estimating tools and evidenced by the feld data that support the decisions made to use this construction methodology. Because the FRC can be directly pumped to elevated slabs, the use of cranes for lifting reinforcing bars is eliminated. The overall simplifcation of the jobsite signifcantly improves the physical and labor-intensive tasks that would be otherwise needed if reinforcing bars were to be placed. This simplifcation has the potential to improve safety on the jobsite. A reduction in personnel for placing and fnishing may also occur when compared with the traditional RC structures. Moreover, as the requirements for concrete cover are eliminated in the FRC technology, an additional reduction in labor and material cost may occur. The SFRC may be somewhat thinner than the traditional slab only when design verifcations for serviceability and ultimate limit states are assessed.
3.2.2 Strength and ductility—The ductility of the slabs discussed herein is greater than comparable slabs that are reinforced using continuous transverse and longitudinal reinforcing bars. The analytical strength of the slabs calculated by means of standard rectangular stress block calculations tend to underestimate the experimental results. This suggests that the failure mechanisms may be governed by yield-line theory. The steel fbers with undulated, conical, or hooked ends provide improved mechanical bond and are shown to be able to provide suffcient structural capacity. Other conventional reinforcing bars are provided to reinforce the corners of lift shafts, staircases, manholes, and other reentrant corners. 3.2.3 Construction scheduling—E-SFRC slab systems have the same advantages as G-SFRC slab systems in addition to improving the architectural freedom to use creativity with non-orthogonal shapes of foor plans that may otherwise be quite diffcult with traditional reinforcing bar layouts. Because drop panels and beams can be omitted, forming becomes easier and quicker. Savings in crane costs and scheduling time is obvious because only a small amount of reinforcing bar is needed to be lifted up to the foor level. If self-consolidating mixtures are used, installation does not require internal or poker vibrators, which may leave voids in concrete, and reduces noise pollution (Salehian and Barros 2015). Reduction of layers of reinforcing bars or reliance on welded wire reinforcement signifcantly improves mobility and safety of personnel.ACI 544.6R pdf download.