EFFECTS OF STEEL FIBERS ON SHORT BEAMS LOADED IN SHEAR

30 fiber-reinforced concrete beams were tested under varying conditions to study the influences of steel fibers on cracking and ultimate loads, as well as on deformation and failure characteristics. Several existing methods for estimating flexural or shear resistance were compared and discussed through their prediction of test results. Increased cracking and ultimate loads and improved ductility, mostly dependent on the volume fraction of fibers, were observed. The deformation concentrated at 1 or 2 major cracks, however, collapsed the beams regardless of the failure mode. Nonetheless, the beams, which failed in a flexural and a shear-flexural mode, did exhibit good ductility. Flexural capacities predicted by the procedure given by ACI Committee 544 were very conservative. The predicted shear capacities using different formulas varied considerably. The feasibility of the application of a plastic theory in determining shear resistance was examined, offering much promise.