Lateral Confinement of Concrete Using High-Strength Fiber Reinforcement

在混凝土表面螺旋缠绕环氧高强芳纶纤维预拉伸带对混凝土进行横向约束，提高了混凝土的抗压强度，增加了最大可达应变(延性)，提供了抗剪机理，并抑制了纵向钢筋屈曲。与钢绞线或钢棒相比，纤维胶带的主要优点是：接触面积更大，轮廓更低，没有腐蚀，即使是棱柱形截面也可以预拉伸，并且可以自动安装。在本项目中，采用1/4比例的不同截面和纵横向钢筋配筋特性的试件，在轴向、剪切和弯曲组合循环荷载作用下，对这种加固/修复技术进行了广泛的试验和分析研究。加固带由一个由编织芳纶(芳纶)纤维制成的扁管组成，具有不同的面积、螺距和预应力水平。这项拟议的研究使用了三井建设株式会社以前在该公司参与下建造的一台绕线机，目的是继续和改善在使用新建筑材料方面的国际科学合作。

Lateral confinement of concrete by means of spirally winding a pretensioned tape of epoxy-impregnated high-strength aramid fiber onto the concrete surface increase the compressive strength of concrete, increases the maximum attainable strain (ductility), provide a mechanims for shear resistance, and inhibits longitudinal reinforcement buckling. The primary advantages of fiber-made tapes as compared to steel strands or rods are: higher contact area and low profile, no corrosion, possibility of pretensioning even with prismatic cross sections, and automatic installation. In this project, an extensive experimental and analytical study of this strengthening/repair technology is conducted using 1/4 scale specimens with different cross sections and longitudinal/transverse steel reinforcement characteristics, and subjected to combined cyclic loads (axial, shear, and bending). The reinforcing tape consists of a flattened tube made of braided aramid (Kevlar) fiber with different areas, spiral pitches, and levels of prestress being investigated. A winding machine previously constructed by Mitsui Construction Co. with the participation of this PI, is used for the proposed research with the objective of continuing and improving international scientific cooperation on the use of new construction materials.