Fundamental mechanics that govern the flexural behaviour of reinforced concrete beams with fibre-reinforced concrete

Tests on steel reinforced concrete beams made with fibre-reinforced concrete have shown many benefits over reinforced concrete beams made with conventional concrete, such as increased strengths and ductilities and reduced deflections and crack widths. There has been much empirical research on quantifying the tensile and compressive fibre-reinforced concrete material properties in particular those subsequent to tensile flexural cracking or sliding of compression wedges. However, it is quite difficult to incorporate these material properties in strain-based approaches as they cannot cope with the rigid body movements of cracking or sliding directly. In this article, a segmental displacement-based approach is described that can both incorporate all the measured material test results directly and also explain the fundamental mechanics that governs the flexural behaviour of reinforced concrete beams made with fibre-reinforced concrete. The approach is generic in that it can cope with any type, geometry and strength of fibre-reinforced concrete and any shape or size of beam. The approach is described in a form suitable for the development of a numerical model and is illustrated via comparison to a published test result.