The present research is concerned with the modelling of the structural behaviour of steel
fibre-reinforced concrete (SFRC) using non-linear finite-element (FE) analysis. Key
structural response indicators such as load-deflection curves, strength, stiffness,
ductility, energy absorption and cracking were examined. In particular, the potential for
fibres to substitute for a reduction in conventional transverse reinforcement was studied.
Such reduction is highly desirables in practice as it helps alleviate reinforcement
congestion, often experienced in the seismic detailing of critical regions such as beam-column
joints. Thus two key parameters were considered, namely reducing transverse
reinforcement while increasing the amount of fibres. The reduction in conventional
reinforcement was achieved mainly by increasing stirrups spacing (and also by reducing
double-hoop arrangement commonly used in seismic detailing of joints).
The behaviour of SFRC structural elements was studied under both monotonic and
reversed-cyclic loadings (the latter used to mimic seismic action). Emphasis was
initially focused on the study of available experimental data describing the effect of
steel fibres on the post-cracking response of concrete. Consequently the SFRC
constitutive model proposed by Lok and Xiao (1999) was selected. The numerical
model was calibrated against existing experimental data to ensure the reliability of the
FE predictions. Subsequently, further analyses were carried out investigating three main
case studies namely, simply supported beams, two-span continuous (i.e. statically-indeterminate)
columns, and both exterior and interior beam-column joints. Parametric
studies were carried out covering the full practical range of steel fibre dosages and
appropriate amounts of reduction in conventional transverse reinforcement. The results
show that steel fibres increase the load-carrying capacity and stiffness (thus enhancing
response at both the serviceability and ultimate limit states, which are important design
considerations). Fibres were found also to improve ductility (as well as altering the
mode of failure from a brittle to a ductile one).