Behavior of Slender Steel-Concrete Composite Columns Wrapped with FRP Jackets

This paper studies the influence of slenderness on the behavior of steel-concrete composite columns encased in fiber-reinforced polymer (FRP) jackets. The composite columns are composed of steel I-sections that are partially encased by concrete and fully wrapped with epoxy-saturated glass and carbon FRP sheets. A total of nine specimens were tested with different slenderness parameters and heights ranging between 500 and 3,000 mm. The confining pressure provided by the FRP jacket and the composite action between the constituent materials resulted in an enhanced compressive behavior of the composite columns. The compressive strength, elastic axial stiffness, and energy dissipation capacity of the composite columns increased by a ratio of up to 5.2, 2.5, and 14.0, respectively, compared with that of the bare steel columns counterparts. A capacity curve, which shows the compressive strength of the composite columns for various slenderness parameters, was developed based on the experimental results.