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.
