Effect of fibre layup and bearing length on the web-crippling behaviour of pultruded GFRP profiles

This paper presents an experimental study about the web-crippling behaviour of pultruded glass fibre reinforced polymer (GFRP) profiles, loaded under end two flange (ETF) and interior two flange (ITF) configurations, with varying bearing lengths. The study was performed to address two significant research needs: (i) to obtain a better understanding of the web-crippling phenomenon in GFRP profiles with different cross-sections and fibre layups; and (ii) to provide additional experimental data on web-crippling, necessary to validate advanced numerical models and to develop design formulae. The experimental programme included materials with different levels of transverse reinforcement, provided by a total of four suppliers. These significant differences in the fibre layups among the profiles tested did not seem to affect the stiffness and ultimate loads significantly. To the contrary, the bearing length was found to have a significant effect on the failure mode, stiffness and ultimate load of all I-section profiles. Moreover, and despite their significant differences in terms of geometrical and material properties, all I-section profiles presented similar transverse compressive strain distributions, when loaded in the same conditions, showing that changes in fibre layups had a negligible effect on the effective bearing length of the various specimens.