Author(s):
Barros, Joaquim A. O. 
; Salehian, Hamidreza ; Pires, Miguel ; Gonçalves, Delfina
Date: 2012
Persistent ID: http://hdl.handle.net/1822/21572
Origin: RepositóriUM - Universidade do Minho
Subject(s): Fibre reinforced concrete; Elevated slab; Yield line theory
Description
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.
