Abstract Fiber-reinforced cementitious matrix (FRCM) systems have recently emerged as an innovative technique to strengthen and retrofit reinforced concrete structures. These non-corrosive systems involve the use of high strength reinforcing textiles sandwiched between layers of cementitious mortars. This paper aims to study the effect of retrofitting newly constructed short columns with FRCM using PBO type of textiles. The experimental program consisted of testing 4 rectangular columns and 4 circular columns under concentric loading. All columns had a reinforcement ratio of 0.02 and were cast with concrete of 30 MPa compressive strength. For each type of cross-section, columns were wrapped with 1, 2 or 4 layers of PBO FRCM. Overall, the strengthened columns exhibited higher load carrying capacity than their control unwrapped counterpart with an increase ranged between 5.1% and 36%. The confining effect of FRCM layers was more pronounced in the circular columns than in the square ones. It was also noticed that all columns exhibited similar responses in terms of load -strain relationship irrespective of the column shape and the number of FRCM layers used. Furthermore, the displacement levels increased as the number of layers increased which indicated an increase in ductility of columns wrapped with FRCM.

中文翻译：

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同心荷载下用 FRCM 加固的圆柱和方柱

摘要 纤维增强水泥基体 (FRCM) 系统最近作为一种增强和改造钢筋混凝土结构的创新技术出现。这些非腐蚀性系统涉及使用夹在水泥砂浆层之间的高强度增强纺织品。本文旨在研究使用 PBO 型纺织品用 FRCM 改造新建短柱的效果。实验程序包括在同心载荷下测试 4 个矩形柱和 4 个圆形柱。所有柱子的配筋率为 0.02，并用 30 MPa 抗压强度的混凝土浇筑。对于每种类型的横截面，柱子都用 1、2 或 4 层 PBO FRCM 包裹。全面的，加强柱的承载能力比未包裹的对照柱更高，增幅介于 5.1% 和 36% 之间。FRCM 层的约束效应在圆形柱中比在方形中更明显。还注意到，无论柱的形状和使用的 FRCM 层数如何，所有柱在载荷-应变关系方面都表现出相似的响应。此外，位移水平随着层数的增加而增加，这表明用 FRCM 包裹的柱的延性增加。还注意到，无论柱的形状和使用的 FRCM 层数如何，所有柱在载荷-应变关系方面都表现出相似的响应。此外，位移水平随着层数的增加而增加，这表明用 FRCM 包裹的柱的延性增加。还注意到，无论柱的形状和使用的 FRCM 层数如何，所有柱在载荷-应变关系方面都表现出相似的响应。此外，位移水平随着层数的增加而增加，这表明用 FRCM 包裹的柱的延性增加。