Effect of hooked steel fibers on shear strength of beams without stirrups

Abstract

This study explores the impact of incorporating hooked steel fibers on the shear strength of concrete beams. Finite element analysis was employed to analyze eighteen simply supported steel fiber-reinforced concrete beams. The investigation assesses the effects of three different fiber percentages, three shear span-to-depth ratios, and two cube compressive strengths of concrete on the shear strength of the beams. All model beams had a width of 150 mm and a depth of 250 mm. The primary variables included three fiber percentages (0%, 0.5%, and 0.75%), three shear span-to-depth ratios (1.0, 1.25, and 1.5), and two cube compressive strengths of concrete (30 MPa and 60 MPa). No shear stirrups were incorporated within the span, and the two longitudinal bars were hooked upwards behind the supports and enclosed by two stirrups at each end. To validate the finite element (FE) simulation, the study used test results available in the literature for steel fiber-reinforced concrete beams. The results from the finite element analysis were compared with the test values, demonstrating good agreement. The findings underscore the reliability of the analysis in predicting shear strength in terms of failure load and failure mode for steel fiber-reinforced concrete beams.The finite element analysis focused on eighteen simply supported steel fiber-reinforced concrete beams, primarily investigating the influence of hooked steel fibers on shear strength. The study examined the behavior of these beams, including load-deflection curves, load-ultimate shear strength curves, and shear failure modes such as diagonal cracking, ultimate shear strength, and ultimate shear load capacity. The results from the finite element analysis emphasized the significant impact of hooked steel fibers on the shear strength of concrete beams. The ultimate shear strength was observed to increase with higher concrete compressive strength, lower shear span-to-depth ratios, and increased fiber volume. Additionally, as the fiber content increased, the failure mode transitioned from shear to flexural. The influence of fiber decreased by 2.33% to 63.47% with increasing concrete compressive strength (30 MPa to 60 MPa) for shear spanto-depth ratios of 1.25 and 1.5, and decreasing shear span-to-depth ratio.