BENDING STIFFNESS IMPROVEMENT FOR THE EXISTING MEMBERS USING LAMINATED THIN FRP SLIT PIPE BY UNBONDED RESTRAINING MECHANISM

Abstract

FRP materials that have superior material properties, e.g., high weight strength ratio and corrosion resistance, have been widely applied to industrial, aerospace, and construction use in recent. In the construction field, the repair and strengthening method using FRPs has been strongly researched and developed. Almost all methods adopt the adhesive bonding method to apply FRPs to the existing structures. This paper shows a new strengthening method and mechanism using thin FRP restrainers. We propose the use of slitted thin FRP pipes for strengthening. The FRP pipes are wrapped with rotational lamination around the existing pipe member to increase the bending stiffness and buckling load. Because of the high elastic deformation performance of FRP, the plastic band-like application method can be used for the wrapping. As a result, the proposed strengthening method is demonstrated successfully, and it is clearly shown that the bending stiffness and buckling load are increased by the present method.