Optimum Dosage of Deformed Steel Fibres in Fibrous Concrete Beams under Predominant Shear
This study presents an analytical approach to evaluate an optimum content of deformed steel fibres in shear-dominated fibrous concrete beams in order strength and ductility requirements to be satisfied. The proposed methodology is based on the calculations of the flexural and shear capacities and to the concept that a pure flexural response should be achieved. The goal of this method is to evaluate the minimum required value of the fibre factor, F, which expresses the effect of the volume fraction and the geometrical characteristics of the used steel fibres. The calculation of F is achieved using a cubic formula derived from the described procedure. Fibres can be used either as the only shear reinforcement or in combination with stirrups. Test results from 47 beams of the literature are used to verify and to illustrate the application of the proposed approach. Comparisons between experimental and predicted results showed a very good agreement. Design charts have also been plotted by the implementation of this methodology as an analysis tool.