Flexural modelling of steel fibre-reinforced concrete beams with and without steel bars

• Analytical flexural models for SFRC have been developed and verified.
• Variable rectangular stress blocks for both tension and compression are proposed.
• The models have been verified using experimental data, giving good predictions.

This paper outlines analytical flexural models for steel fibre reinforced concrete (SFRC) with and without steel bars. The models are developed for strain softening, deflection hardening SFRC. Models for the determination of flexural capacity of SFRC rectangular sections based on equivalent stress blocks for both compression and tension are developed using strain compatibility and force equilibrium principles. The equivalent stress blocks are derived from an elastic perfect-plastic model for compression, and an elastic-constant post-peak response for tension. The models are verified using experimental data. Sensitivity analysis is conducted to assess the predictability of the models with varying model parameters. When compared with existing models, the proposed models fairly predict the flexural capacity of the SFRC beams. The models may allow the user to determine model uncertainties and hence provide for appropriate safety margin for design.