Shear behavior of steel fiber high-strength reinforced concrete continuous beams

In this paper the shear behavior of steel fiber high strength reinforced concrete continuous beams was studied. A series of ten continuous beams were fabricated and tested to failure under two concentrated loads in order to investigate the effect of several important parameters on the shear behavior of such type of beams. These parameters included: the steel fiber volume content and the shear span to depth ratio. For all tested beams the initiation of cracks and its propagation was observed and recorded. Deflections and steel strains were measured thus load-deflection and load-strain relationships were detected. Also, failure loads and failure modes were observed for all tested beams. Test results have revealed the beneficial effects of the inclusion of steel fibers in the enhancement of shear behavior of high strength concrete continuous beams. The presence of steel fibers significantly enhanced the post cracking tensile strength of concrete and therefore the shear strength of continuous beams was improved. Also, it was found that the brittle nature of failure in the case of high strength concrete continuous beams was transformed into a more ductile one for beams containing steel fibers. Finally, the experimental results for shear strength of tested continuous beams were compared to theoretical predictions from empirical equations found in the literature for the estimation of shear strength of simply supported steel fiber high strength concrete beams.