Shear strengthening of rectangular and circular concrete members using FRP

This paper provides the background and guidance relating to the design methods proposed in The Concrete Society’s Technical Report 55 (TR55) third edition [1] for the shear strengthening of rectangular and circular reinforced concrete members using fibre composite materials.

When TR55 was updated to the third edition the content was aligned with the suite of Eurocodes for structural design. There were several challenges involved in updating the shear strengthening requirements to align with BS EN 1992-1-1 [2]. In particular, the approach for shear resistance of reinforced concrete members with shear reinforcement in BS EN 1992-1-1 [2] is different in philosophy from the methods previously used in BS8110 [3] and BS5400-4 [4], since it includes a variable angle truss method. Furthermore, BS EN 1992-1-1 [2] does not provide adequate guidance on shear resistance of circular sections.

This paper considers how these challenges have been addressed in TR55 [1] and provides new guidance on the design of fibre-reinforced polymer (FRP) for shear strengthening using a Eurocode-aligned approach.