A phenomenological design equation for FRP columns with interaction between local and global buckling

Abstract A design equation for fiber reinforced plastic columns is presented in this paper, based on the interaction between local (flange) and global (Euler) buckling observed during testing of the FRP columns included in this investigation. An existing interaction equation is adapted to account for the modes of failure observed in columns made of fiber reinforced composite materials. Experimental data generated during this investigation are presented and used to validate the interaction equation and to obtain the interaction constant. A slenderness ratio is proposed and used to present a plot of buckling for all sections and column lengths (short, long, and intermediate). An expression for the optimum column length to be used in the experimental determination of the interaction constant is proposed.