This study aims to investigate the effects of the geometrical properties and volume content of steel fibers on the shear resistance of reinforced high-strength concrete (HSC) beams without stirrups. Hooked-end and twisted steel fibers with different aspect ratios ranging from 60 to 100 were used at volume fractions of 0.5%–1.0%. The shear strength of HSC beams without stirrups significantly increased due to the addition of steel fibers and by increasing their volume fraction by up to 1.0%, resulting in approximately 1.7 times higher shear resistance. A higher fiber aspect ratio was effective in improving the resistance to shear failure of HSC beams without stirrups and in enhancing beam deformability relative to the increase in shear strength. Using twisted steel fibers led to better shear resistance than hooked-end steel fibers, resulting in 1.11- and 3.34-times higher shear strength and ductility at the same fiber volume fraction on average. The shear strength of steel fiber-reinforced concrete (SFRC) beams was also predicted using eight different models. Narayanan's model most precisely predicted the shear strengths of reinforced SFRC beams without shear reinforcement, with an average ratio of 1.16. The shear strength increased with the decrease in shear span-to-depth (a/d) ratio and the increase in the fiber factor. The contribution of steel fibers to shear strength was greater for deep beams than slender beams. The predicted shear strengths of deep beams and high-strength SFRC showed a significant deviation from the actual value and required careful consideration.

中文翻译：

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钢纤维用量和几何特性对无剪钢筋高强混凝土梁抗剪性能的影响


本研究旨在研究钢纤维的几何特性和体积含量对无箍筋钢筋高强混凝土（HSC）梁抗剪强度的影响。使用不同长径比范围为 60 至 100 的钩端和加捻钢纤维，体积分数为 0.5% 至 1.0%。由于添加了钢纤维并将其体积分数增加了 1.0%，无箍筋 HSC 梁的抗剪强度显着提高，抗剪强度提高了约 1.7 倍。较高的纤维纵横比可有效提高无箍筋 HSC 梁的抗剪破坏能力，并相对于剪切强度的增加提高梁的变形能力。使用加捻钢纤维比钩端钢纤维具有更好的抗剪性能，在相同的纤维体积分数下，抗剪强度和延展性平均高出 1.11 倍和 3.34 倍。钢纤维混凝土 (SFRC) 梁的抗剪强度也使用八种不同的模型进行了预测。 Narayanan 的模型最精确地预测了无抗剪钢筋的钢筋 SFRC 梁的抗剪强度，平均比率为 1.16。剪切强度随着剪切跨深比 (a/d) 的减小和纤维系数的增加而增加。钢纤维对深梁抗剪强度的贡献大于细梁。深梁和高强钢纤维混凝土的预测抗剪强度与实际值存在较大偏差，需要仔细考虑。