Investigation into CFRP laminate anchorage systems utilising bi-directional fabric wrap

The increasing challenges faced to strengthen existing concrete bridges and infrastructure has resulted in intensive research and the introduction of carbon fibre reinforced polymers (CFRP). It has been demonstrated that failure of concrete structures retrofitted with CFRP usually occurs by de-lamination of the CFRP from the concrete substrate. As a result, the introduction of CFRP anchorage systems to increase the efficiency of CFRP solutions remains an area of great potential. What follows is the third paper of a series presenting the results of six types of CFRP anchorage solutions. Earlier publications highlighted the benefits of uni-directional fibres and of mechanical substrate strengthening. Together these formed anchorage types 1, 2 and 3 designed to enhance CFRP anchorage performance. The present paper focuses on the application of CFRP bi-directional fabric to the ends of CFRP laminates in arrangements that form the remaining anchorage types 4, 5 and 6. The benefits of the bi-directional CFRP anchorage system has resulted in significantly improved: fibre utilisation levels and increased ductility, which in some cases has resulted in laminate rupture. The higher CFRP strain levels achieved warrants the adoption of less stringent strain limitations used in design, resulting in both material and cost savings.