Shear resistance of RC members with closed FRP jacket for Eurocode 8

The shear resistance computed using Annex J of Part 1–1 of Generation 2 of Eurocode 2—on strengthening of RC members for static loads with externally-bonded Fibre-reinforced-polymers (FRPs)—exceeds by about 25% on average the cyclic shear resistance of 64 FRP-jacketed shear-critical RC specimens in the international literature. The semi-empirical cyclic shear resistance approach for FRP-wrapped RC members in Annex A of Part 3 of Generation 1 of Eurocode 8 is in good average agreement with the results of these tests, but conflicts with the rational, mechanics-based approach for shear resistance against static actions in Generation 2 of Eurocode 2, which has already been adopted in Generation 2 of Eurocode 8 for members without FRP jackets, adapted to the specific needs of seismic design. This latter approach is modified and extended to cover RC members with closed FRP jackets in a more technically sound way than in Annex J of Generation 2 of Eurocode 2. The new approach fits the available cyclic test results without bias or lack-of-fit with respect to the key variables controlling cyclic shear resistance, gives slightly better accuracy than the semi-empirical one in Generation 1 of Eurocode 8 and does much better in correctly identifying as not failing in shear FRP-wrapped RC members which have failed in flexure or not failed at all during cyclic testing.