The use of steel fibres for the reinforcement of concrete structures is as competitive as higher is the support redundancy, and as many stress components develop in the structure. Slabs supported on piles or columns (here designated by elevated slabs) are this type of structures, where the statically indeterminate degree is dependent on the number of columns/piles, and five stress components are installed, three of which lead to membrane force and bending moment components, and the other two out-of-plane stresses generate the shear force components. When using relatively high content of steel fibres (1 to 1.5% in volume) of large aspect ratio (65 to 80), steel fibre reinforced concrete (SFRC) of quite significant post-crack residual tensile strength can be built, able of providing an ultimate moment much higher than its cracking moment. The benefits guaranteed by the fibre reinforcement at the cross section level are amplified at the structural level due to the stress redistribution provided by the support redundancy character of this type of structures, and by the reinforcement mechanisms assured by fibres bridging the cracks, leading to an ultimate load carrying capacity for the SFRSC slab that is much larger than the load at crack initiation. Adding the benefits of fibre reinforcement to those derived from the self-consolidating character of a self-compacting concrete (SCC), a high performance structural material can be obtained, here designated by steel fibre reinforced self-compacting concrete (SFRSCC). The behaviour of SFRSCC slab supported on columns is investigated in the present work by applying the yield line theory (YLT) to available data generated from real scale tests and performing parametric studies in order to evidence the influence of relevant parameters for the effectiveness of this innovative structural system. A SFRSCC was developed, its relevant properties were characterized, and it was used to build a ¼ scale elevated steel fibre reinforced concrete (ESFRC) slab system prototype. The results of the first phase of the loading test program are presented.
Barros, J.A.O.; Salehian, H.; Pires, N.M.M.A., Gonçalves, D.M.F., “Design and testing elevated steel fibre reinforced self-compacting concrete slabs”, 8th RILEM International Symposium on Fibre Reinforced Concrete: challenges and opportunities, Eds: Joaquim Barros et al., 12pp., 19-21 September 2012. http://hdl.handle.net/1822/21572