A Discussion on the Local Buckling of Pultruded GFRP I-Section Columns

In this paper, a discussion on the local buckling (LB) behaviour of pultruded glass-fibre reinforced polymer (pGFRP) columns and on the appropriate techniques for testing and analysing data is presented. Comments on the influence of relevant parameters such as length, end-conditions, material properties, flange-to-web width ratio and post-buckling behaviour in the experimentally determined critical loads and theoretical predictions are made. Signature curves (critical stress x length plots) and global x local buckling slenderness ‘maps’ are presented as important ‘tools’ for predicting column behaviour. To support the discussion, the results of an ongoing experimental program involving eighteen stub columns with clamped-ends and different flange-to-web width ratios are reported. Comparison with theory is made and differences between tests and predictions are explained.