Pre-impregnated carbon fibre reinforced composite system for patch repair of steel I-beams

The application of fibre-reinforced polymer (FRP) composites for strengthening and rehabilitation of structural elements has become essential in recent years. However, most of the research and developments focused on using FRP strips or plates, which are limited in strengthening metallic structures with flat steel surfaces. In most cases, the damage due to corrosion are localised in the beam which requires more flexible composite repair system. In this study, a pre-impregnated carbon fibre reinforced epoxy repair system is evaluated through mechanical testing of tensile, double strap shear joint specimens, and structural testing of rehabilitated I-beams. The results showed that use of vacuum during laminate manufacture resulted in better mechanical properties due to the better consolidation of the fibre layers. A bond length of 120 mm provides a more consistent and reliable adhesively bonded joint and is representative of the bond strength of the rehabilitated steel beam. Finally, the patched carbon prepreg system successfully repaired the simulated crack and corrosion defects in steel I-beams, restoring them to their original load carrying capacity and stiffness.