ABSTRACT
The use of steel fibers as shear reinforcement in high-strength concrete beams is investigated in this study. Sixteen high-strength fiber reinforced concrete beams were tested by two point loading. The variables were the steel fiber content (0, 0.5, 1.0 and 1.5 %) and the shear-span/depth (a/d) ratio (1,2,4 and 6). Concrete with average compressive strength of about 96 MPa (14,000 psi) and one type of hooked steel fiber were used in this investigation. Fiber addition noticeably improved the shear strength of the tested high-strength concrete beams and this strength enhancement significantly increases as the a/d ratio decreases. By modelling of the shear strength due to the fibers as vertical stirrups, the two equivalent factors corresponding to shear reinforcement ratio and spacing are determined. Based on the test results, an empirical equation is proposed to predict the extra strength provided by the steel fibers.
