Shear strengthening of RC beams with prestressed NSM CFRP: Influencing factors and analytical model

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES Composite Structures Pub Date : 2024-06-06 DOI:10.1016/j.compstruct.2024.118262

Hengliang Guo , HaoHan Liao , Miao Su , Bai Zhang , Shaofang Li , Hui Peng

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Abstract

This study proposes the application of prestressed near-surface-mounted (NSM) carbon-fiber-reinforced polymer (CFRP) technique in the field of the shear-strengthening of bridges for the first time. Fourteen reinforced concrete (RC) beams shear strengthened with prestressed NSM CFRP were tested under static load. The effect of the CFRP prestressing level, spacing, angle, and end-anchorage measures on the shear-strengthening behavior was evaluated. The experimental results demonstrate that the ultimate shear capacity of prestressed NSM CFRP shear-strengthened beams increased by 65–127% when compared to that of the reference beams, and the width of shear cracks was effectively suppressed. The failure mode of prestressed NSM CFRP shear-strengthened beams without end-anchorage measures was web concrete cover separation, which can be suppressed using a CFRP U-jacket and through-beam screw. Increasing the CFRP prestressing level and percentage enhanced the ultimate shear capacity and cracking resistance of the strengthened beams. However, an excessively high CFRP percentage and prestress level combination resulted in large shear crack angles and decreased the shear contribution of CFRP and concrete. Finally, an analytical model based on the modified compression field theory (MCFT) was proposed to predict the flexural-shear load response of strengthened beams, which was in agreement with the experimental results.

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使用预应力 NSM CFRP 对 RC 梁进行剪切加固：影响因素和分析模型

本研究首次提出将预应力近表面安装（NSM）碳纤维增强聚合物（CFRP）技术应用于桥梁抗剪加固领域。在静荷载作用下，对 14 根采用预应力 NSM CFRP 进行剪切加固的钢筋混凝土 (RC) 梁进行了测试。评估了 CFRP 预应力水平、间距、角度和端部锚固措施对剪力加固行为的影响。实验结果表明，与基准梁相比，预应力 NSM CFRP 剪力加固梁的极限抗剪承载力提高了 65-127%，剪力裂缝的宽度也得到了有效抑制。没有端部锚固措施的预应力 NSM CFRP 剪力加固梁的破坏模式是腹板混凝土盖板分离，使用 CFRP U 型夹具和穿梁螺杆可以抑制这种破坏模式。提高 CFRP 预应力水平和百分比可增强加固梁的极限抗剪能力和抗裂性。然而，过高的 CFRP 百分比和预应力水平组合会导致较大的剪切裂缝角度，并降低 CFRP 和混凝土的抗剪贡献。最后，提出了一个基于修正压缩场理论（MCFT）的分析模型，用于预测加固梁的挠剪载荷响应，该模型与实验结果一致。

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来源期刊

Composite Structures 工程技术-材料科学：复合

CiteScore

12.00

自引率

12.70%

发文量

1246

审稿时长

78 days

期刊介绍： The past few decades have seen outstanding advances in the use of composite materials in structural applications. There can be little doubt that, within engineering circles, composites have revolutionised traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable materials for construction. Composite Structures, an International Journal, disseminates knowledge between users, manufacturers, designers and researchers involved in structures or structural components manufactured using composite materials. The journal publishes papers which contribute to knowledge in the use of composite materials in engineering structures. Papers deal with design, research and development studies, experimental investigations, theoretical analysis and fabrication techniques relevant to the application of composites in load-bearing components for assemblies, ranging from individual components such as plates and shells to complete composite structures.