A combination of vertical stirrups and randomly distributed fibers in the matrix enhances the diagonal
tension capacity of concrete beams. The degree of increase in the diagonal tension capacity is a function
of the shear span/depth ratio of a beam. This ratio determines the mode of failure in normal beams that
do not fall in the category of deep beams and brackets as detailed by Nawy (2008). Williamson (1978)
found that when 1.66% by volume of straight steel fibers are used instead of stirrups, the shear capacity
increased by 45% over beams without stirrups. When steel fibers with deformed ends were used at a
volume ratio of 1.1%, the shear capacity increased by 45 to 67% and the beams failed by flexure. Using
crimped-end fibers increased the shear capacity by almost 100%.