Shear capacity of fiber-reinforced concrete under pure shear

Concrete members with steel fibers generally increase the shear and torsional strength of concrete; however, supplementing or replacing the stirrups with steel fibers is still not an accepted practice. Previous studies documented many tests of steel fiber-reinforced concrete (SFRC) beams with and without stirrups that failed in shear. The results indicated that the shear span-depth ratio adversely affects the shear capacity. As part of this experimental study, the picture frame fixture was used to test 20 SFRC samples under in-plane pure shear loading. Samples included hooked, crimped and arched-crimped steel fibers with varying volume fractions. Models for SFRC beam shear strength were reexamined using the current test data. The evaluation indicated that the model developed by Ashour provided the most accurate estimates to account for fibers efficiency in contribution to shear strength. Furthermore, the hooked steel fibers were shown to be more efficient than crimped fibers, and further increase of fiber volume fraction beyond 1 percent of crimped fibers did not result in significant improvements in the shear strength