Factors Affecting the Ultimate Condition of FRP-Wrapped Concrete Columns

Abstract

Fiber reinforced polymer (FRP)-wrapped circular concrete columns under axial compression usually fail as a result of FRP rupture in the hoop direction. The average measured hoop strain in the FRP jacket at failure of such columns, i.e., the apparent FRP rupture strain, is typically considerably lower than the ultimate tensile strain obtained from tensile tests of flat coupons. A large scatter also exists in the measured rupture strains over the surface of an FRP-wrapped column at ultimate failure. No rational model based on sound theories is currently available to explicitly consider the reduction of the apparent FRP rupture strain in design. This paper discusses the possible failure modes of FRP-wrapped concrete columns and the factors that may play a role in the initiation of failure. Further research needs and the possible consequences for the optimized design of FRP-wrapped concrete columns are discussed.