Behavior of RC columns strengthened with UHPFRC jackets through grooving method under eccentric loading: A comparative evaluation of steel and synthetic macro fibers in UHPFRC
Behavior of RC columns strengthened with UHPFRC jackets through grooving method under eccentric loading: A comparative evaluation of steel and synthetic macro fibers in UHPFRC
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偏心荷载下通过开槽法用 UHPFRC 护套加固的 RC 柱的性能：UHPFRC 中钢和合成粗纤维的比较评估
DOI：
10.1002/suco.202100551
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发表时间：
2022
影响因子：
3.2
通讯作者：
Hadi Bahmani
中科院分区：
文献类型：
--
作者：
Saadat Eshaghi;D. Mostofinejad;Alireza Saljoughian;Hadi Bahmani
本研究旨在研究用超高性能纤维增强混凝土（UHPFRC）护套和纤维增强聚合物（FRP）包裹改造的钢筋混凝土（RC）圆柱在同心和偏心载荷下的行为。在本研究中，首次使用含有合成粗纤维（条片）的 UHPFRC 护套。然后将结果与含有钢纤维的 UHPFRC 获得的结果进行比较。此外，为了改善混凝土护套对偏心荷载下柱行为的影响，采用了纵向开槽方法（GM）的创新界面处理。为此，对 15 个直径为 120 毫米、高度为 500 毫米的圆柱体施加 0、30 和 60 毫米的负载偏心率。因此，六根柱子用厚度为 15mm 的 UHPFRC 护套进行了改造，其中包括钢和合成粗纤维（条片），而另外六根柱子则用 UHPFRC 护套和间歇玻璃纤维增强塑料 (GFRP) 经纱进行了加固。实验结果表明，承载能力随着偏心距的增加而增加，偏心距为0、30和60mm时，用含有GFRP经线和钢纤维的UHPFRC护套加固的试件的承载能力分别提高了283%、303%和401%。此外，与相应对照样本的相同参数相比，用包含钢纤维和 GFRP 经线的 UHPFRC 护套改装的样本在零毫米加载偏心下的延展性和能量耗散分别提高了 198% 和 530%。最后，采用先前的理论模型推导出轴向载荷-弯矩（P-M）相互作用图，从而很好地验证了本研究的结果。
This study aims to examine the behavior of reinforced concrete (RC) circular columns retrofitted with ultra‐high‐performance fiber‐reinforced concrete (UHPFRC) jackets and fiber‐reinforced polymer (FRP) wraps under concentric and eccentric loading. In the present study, for the first time, UHPFRC jackets containing synthetic macro fibers (barchip) were used. The results were then compared with those obtained by UHPFRC containing steel fibers. Moreover, to improve the effect of concrete jacketing on the column behavior under eccentric loading, the innovative interface treatment of the longitudinal grooving method (GM) was applied. For these purposes, 15 such circular columns, 120 mm in diameter and 500 mm in height, were subjected to load eccentricities of 0, 30, and 60 mm. Thus, six columns were retrofitted with UHPFRC jackets 15 mm in thickness that included both steel and synthetic macro fibers (barchip) while another six were strengthened with UHPFRC jackets and intermittent glass FRP (GFRP) warps. The experimental results revealed that load‐carrying capacity raised with the increase of the load eccentricity, as evidenced by enhancements of 283%, 303%, and 401% in the loading capacity of the specimens strengthened with UHPFRC jackets containing both GFRP warps and steel fibers for eccentricities of zero, 30, and 60 mm, respectively, relative to those of the control. In addition, enhancements of 198% and 530% were recorded respectively for ductility and energy dissipation under a loading eccentricity of zero mm in specimens retrofitted with UHPFRC jackets including steel fiber and GFRP warps when compared with the same parameters in the corresponding control specimens. Finally, a previous theoretical model was adopted to derive the axial loading‐bending moment (P–M) interaction diagrams whereby the results of the present study were satisfactorily verified.