Torsion of steel fiber reinforced concrete members

Abstract Addition of steel fibers in concrete improves the mechanical properties of the basic matrix as they slow down the growth of crack and creates pinching forces at the tips of the cracks. Thus, the steel fiber reinforced concrete becomes a better energy absorbing material and is best material for the seismic resistant structures and blast resistant structures. Relatively little research work has been done on the behavioural aspects of this material under pure torsion compared to its behaviour under flexure or shear or under combined loading. Earlier researchers [Int. J. Cem. Compos. Lightweight Concr. 4 (1982) 45, Indian Concr. J. 55 (1981) 222–232, Int. J. Cem. Compos. 2 (1980) 85] reported that addition of fiber in concrete improves the torsional strength and ductility. However, the enhanced properties of SFRC in particular the ductility of the matrix can be achieved when a minimum volume fraction of fiber content is maintained. This investigation aims at understanding the behavioural aspects of plain SFRC members under pure torsion. An empirical formula has been proposed to predict the ultimate torsional strength of the SFRC members under pure torsion.