Interfacial shear stress concentration in FRP- strengthened beams

This paper reports the results of an experimental programme designed to stu dy the interfacial shear stress concentration at the plate curtailment of r einforced concrete (RC) beams strengthened in flexure with externally bonde d carbon fibre-reinforced polymer (CFRP). Specifically, the study looks at the relationship between the CFRP plate thickness and the interfacial shear stress concentration at the plate curtailment, the failure modes of the CF RP-strengthened beams as well as the efficiency of the CFRP external reinfo rcing system. Comparing the experimental results with existing models' pred ictions is another objective of this study. The experimental programme incl uded five RC beams 115 mm x 150 mm cross-section and 1500 mm in length. Fou r of the RC beams were reinforced externally with CFRP plates of different thicknesses. Tests in this study showed that the thickness of CFRP plate af fects not only the load-carrying and deflection capacities of the strengthe ned beam, but also the shear stress concentration at the CFRP/concrete inte rface and the beam failure mode. (C) 2001 Elsevier Science Ltd. All rights reserved.