2.10 Behaviour of FRP strengthened flexural RC elements subjected to degradation influences

Abstract

A series of experiments have been conducted to evaluate the performance of flexural RC elements strengthened by FRPs and the impact of certain degradation issues on the performance of such members. The study examines; (a) imperfections within the FRP/concrete bondline at the strengthening stage, (b) the influence of cyclic loading on FRP strengthened members and, (c) the strengthening of degraded beams due to environmental attacks. The experimental results showed that; (i) the introduction of air-voids between the interface of the composite and concrete bond-line, results in reductions in the ultimate capacities of the retrofitted beams when compared to perfectly bonded FRP beams, (ii) cyclic loading is seen to mitigate the advantages of the external FRP strengthening and the improvements gained in ductility performance of the beams, since the deformations are not as high as in the case of statically loaded elements, (iii) the beam element exposed to an aggressive acidic environment appeared to exhibit an increase in ultimate capacity (79%), when compared to the control element. In conclusion, these experimental studies show that the ductility of RC members was significantly enhanced by the use of FRPs. It was also shown that even in the case of structures subjected to an acidic environment, the FRP strengthening technique is effective and that strengthened members can reach high ultimate capacities. INTRODUCTION EXPERIMENTAL PROGRAMME RESULTS AND DISCUSSIONS CONCLUSION ACKNOWLEDGEMENTS REFERENCES