For this paper, the punching shear behaviour of 18 steel-fibre recycled aggregate concrete (SFRAC) balanced slab–column connections was experimentally investigated and analytically modelled for the following variables: the recycled concrete aggregate replacement level (0, 50 and 100%) and the volume fraction of hooked-end fibres (0, 0.4 and 0.8%). The measured punching shear capacities were practically insensitive to the recycled aggregate replacement levels, although both the inclination of the punching failure surface as well as punching capacities increased with fibre dosage. Relatively, the best performance improvement was obtained at 0.4% fibre dosage wherein the punching capacities and energy absorption increased by 23% and 70%, respectively, as compared to the non-fibrous concrete specimens. Using the experimental results, the authors propose and calibrate a simple strut-and-tie based punching shear predictive model for SFRAC, and undertake a validation using the limited results available in the literature. Among the selected current design codes under appraisal, the most conservative punching shear predictions for the SFRAC specimens were obtained from the Indian code, IS456:2000, whereas relatively more accurate predictions were obtained from the Eurocode 2.

中文翻译：

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钢纤维再生骨料混凝土板的冲切抗剪能力

在本文中，对 18 种钢纤维再生骨料混凝土 (SFRAC) 平衡板柱连接的冲切行为进行了实验研究，并针对以下变量进行了分析建模：再生混凝土骨料替代水平（0、50 和 100%）和钩端纤维的体积分数（0、0.4 和 0.8%）。测得的冲切剪切能力实际上对再生骨料更换水平不敏感，尽管冲切失效表面的倾斜度和冲切能力都随着纤维用量的增加而增加。相对地，与非纤维混凝土试样相比，在 0.4% 的纤维用量下获得了最佳性能改进，其中冲孔能力和能量吸收分别增加了 23% 和 70%。利用实验结果，作者为 SFRAC 提出并校准了一个简单的基于支柱和系杆的冲切预测模型，并使用文献中可用的有限结果进行了验证。在选定的当前评估设计规范中，对 SFRAC 试样的最保守冲切预测来自印度规范 IS456:2000，而相对更准确的预测来自欧洲规范 2。