Several research papers have been dedicated to the investigation of the behaviour of steel
fibre reinforced concrete (SFRC) under several types of forces. Due to its mechanical
property to transfer forces through cracks, it has been observed that SFRC presents substantial
contribution to shear resistence. The present paper investigates the effects of steel fibres on
the shear reinforcement of concrete beams without stirrups under four-point bending tests. For
that purpose, five beams were cast and tested. The dimensions of the beams were
150 mm×300 mm×2700 mm, with 1.54% and 0.16% of tension and compression longitudinal
reinforcement ratios, respectively. Two of the beams were manufactured as references, that is,
without fibres, with one of them having conventional transversal reinforcement with stirrups
and the other with no reinforcement to shear. The other three beams were reinforced with
steel fibres only in the shear span in the proportions of 45 kg/m³, 60 kg/m³ and 75 kg/m³ of
the concrete volume, which represent 0.6%, 0.8% and 1.0%, respectively. Concrete strength
of 30 MPa was used for all the specimens. In addition to the typical characterization of
concrete and steel used in this research, flexural test was performed on SFRC in order to
obtain the residual stress response of the material, whic h is paramount for the evaluation of
the strength of the beam. From the experimental results, it could be concluded that steel fibres
exhibited satisfatory performance under shear forces in the cases of higher fibre content, for
which a change in failure mode was observed: from shear failure to flexural failure.
Furthermore, for the three fibre contents used, the possibility for partial or total replacement
of the transversal reinforcement was confirmed. Additionally, it was demonstrated that the use
of steel fibres in the content of 60 kg/m³ and 75 kg/m³ allows for the reduction of the
longitudinal tension reinforcement to attain flexural strength similar to that of the reference
beam with stirrups
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