Local Buckling of FRP Beams and Columns

Abstract

Fiber‐reinforced plastic (FRP) structural members with open or closed thin‐walled sections are being used as beams and columns for structural applications where buckling is the main consideration in the design. Analytical models for several local buckling modes under axial and shear loading, taking the flange‐web interaction into account, are developed. Experimental data correlating predicted and observed behavior are presented for some commercially available structural shapes. Failure envelopes are developed for box‐ and I‐shape FRP columns and beams. The analytical models presented can be used to predict the behavior of any new pultruted material. The Rayleigh‐Ritz method is used in this work to analyze anisotropic flanges of box and I‐beams. The anisotropy of the material is introduced by ±45° angle‐ply layers introduced recently by pultruted manufacturers to improve the buckling strength of columns as suggested by this investigation.