Behaviour of Steel Fibre Reinforced Concrete Beam under Cyclic Loading

Abstract

This paper describes the influence of steel fibre distribution on the ultimate strength of concrete beams. An experimental & analytical investigation of the behaviour of concrete beams reinforced with conventional steel bars and steel fibres under cyclic loading is presented. It is now well established that one of the important properties of steel fibre reinforced concrete (SFRC) is its superior resistance to cracking and crack propagation. As a result of this ability to arrest cracks, fibre composites possess increased extensibility and tensile strength, both at first crack and at ultimate load and the fibres are able to hold the matrix together even after extensive cracking. The net result of all these is to impart to the fibre composite pronounced post – cracking ductility which is unheard of in ordinary concrete. The transformation from a brittle to a ductile type of material would increase substantially the energy absorption characteristics of the fibre composite and its ability to withstand repeatedly applied, shock or impact loading. Tests on conventionally reinforced concrete beam specimens, containing steel fibres in different proportions, have been conducted to establish load- deflection curves. It was observed that SFRC beams showed enhanced properties compared to that of RC beams with steel fibres. The experimental investigations are validated with the analytical studies carried out by finite element models using ANSYS.