Behavior and design of slender FRP-confined circular RC columns

Strengthening of RC columns through lateral confinement using fiber-reinforced polymer (FRP) jackets is now a widely accepted technique. While extensive research has been conducted on the behavior of such strengthened columns, only a very limited amount of work has examined the slenderness effect in these columns. To correct this deficiency, this paper presents a systematic study on the subject and proposes the first ever design method for slender FRP-confined circular RC columns. A simple theoretical column model for such columns is first described in the paper. Numerical results obtained from this theoretical model are then presented to examine the behavior of these columns to identify the key parameters of influence. A design method based on numerical results from the column model and following the nominal curvature approach is next formulated. The accuracy and safety of the proposed design method is demonstrated through comparison with existing experimental results.