Shear strengthening of reinforced concrete beams using different configurations of externally bonded carbon fibre reinforced plates

This paper deals with research undertaken at Oxford Brookes University into shear strengthening of reinforced concrete beams using externally bonded carbon fibre reinforced plastic plates (CFRP). Thirty-eight reinforced concrete beams of 1.8 m length were constructed and tested and are described in this paper. The relative performance of a group of sixteen beams with the same steel reinforcement but with different amounts of shear strengthening is discussed. All the beams were designed to fail in shear using a spreadsheet program. The spreadsheets were designed to ensure that the beams' flexural capacity exceeded the shear capacity after strengthening. The variables were: main reinforcement ratio, spacing between links in the shear span and different configurations of CFRP plates on shear spans. The concrete had an average compressive strength of 61.76 N/mm². The majority of the beams tested showed a significant improvement in shear strength by the addition of CFRP plates, with increases of between 19–122% over the control beams.