Shear Strength of Fiber Reinforced Concrete (FRC) Beams without Stirrups

Abstract

This paper presents the results of twelve shear tests carried out on simply supported rectangular beams, with a shear span to depth ratio (a/d) of 2.4, under a single concentrated load. Six of the beams contained conventional stirrups and six beams were reinforced with steel fibers as web reinforcement. The parameters were: the effect of fiber volume content (0, 0.5, 1.0, and 1.5%), fiber type (end-hooked or corrugated), and the presence of minimum stirrups. The beam span, beam dimensions, shear span to depth ratio (a/d), and percentage of longitudinal reinforcement were all kept constant. Beam deflection, steel strains, crack propagation, and failure modes were recorded for all the tested beams. The test results showed that the stress at shear cracking and the ultimate shear stress increased with increasing the fiber volume content. When steel fibers with a content of 1.5% were added to the beams with minimum stirrups, the brittle shear failure was changed to ductile flexure failure. The test results were used to evaluate existing empirical equations estimating the shear strength of steel fiber-reinforced concrete beams without stirrups. The evaluation indicated that the equations proposed by Narayanan and Darwish 1987 and Kara 2013 provided the most accurate estimation when compared to the test results.

Keywords

• beams
• shear strength
• steel fiber
• shear reinforcement