Abstract:
Shear strength of longitudinally reinforced normalstrength and high-strength
concrete beams containing either hooked-end or crimped-type of deformed steel fibres
proposed to be used as minimum shear reinforcement has been investigated for various
fibre aspect ratios and volume fractions. The validity of the ACI Building Code
recommended flexural performance criteria governing the use of steel fibres as
minimum shear reinforcement has been examined and its shortcomings are highlighted.
A total of 46 simply-supported scaled beams with a shear span-to-depth ratio of 3.5
were tested to failure under monotonically-increasing, concentrated loads. The
behaviour of the fibrous concrete beams was bench-marked against the performance of
beams conventionally detailed with the minimum shear reinforcement recommended in
the ACI Building Code and the Indian code, IS 456:2000. For both the grades of
concrete, the measured shear strengths across the two fibre types, aspect ratios and the
volume fractions under investigation were higher than a lower-bound value for steel
fibrous concrete given in the literature as well as predicted values of the beams detailed
with the code recommended minimum web reinforcement. Different degrees of
accuracy were obtained when the measured shear strengths were compared with
predictions of selected shear strength models available in the literature. A simple
mechanics-based shear strength predictive model considering the contribution of only
the compressed concrete and tensile resistance of the steel fibrous concrete has been
proposed and validated
