Investigation into CFRP plate end anchorage utilising uni-directional fabric wrap

Abstract

Carbon fibre reinforced polymers (CFRP) has become a very popular method of improving the capacity of structural elements. Failure of CFRP strengthening systems when applied to concrete structures is usually typified by de-lamination of the CFRP from the concrete substrate. Research has shown that anchoring the ends of the CFRP plates or sheets can result in a significantly higher load/stress being reached before de-bonding occurs and that when sufficiently anchored, the CFRP material strain at failure can approach its ultimate strain at rupture. The following is continuation of experimental studies into CFRP anchorage systems used to retrofit concrete structures. It follows from previous investigations conducted by the authors into the bond behaviour of a new anchorage system utilising a mechanically strengthened substrate. The paper presents two alternative anchorages; both utilising uni-directional fabric wrap oriented horizontally across and parallel to the direction of the laminate. Both forms of anchorage are found to be effective in increasing the CFRP to concrete bond strength by distributing contact stresses over a greater area of concrete.