Shear strengthening of RC beams using GFRP sheets

This paper presents an experimental investigation on the shear behaviour of RC beams strengthened with externally bonded glass fibre reinforced polymer (GFRP) sheets. The externally applied GFRP technique is significantly effective to enhance the ultimate load carrying capacity of RC beams. Two beams without GFRP and nine beams wrapped in different lay-up patterns with one/two layers of GFRP sheets have been tested for shear under two-point loading. Loads at first crack of beam/delaminating of GFRP, tearing point of GFRP and ultimate failure of the beam has been noted and types of failure have also been observed. Thereafter, a critical discussion is made with respect to increase in the strength of retrofitted beams with respect to the beam without GFRP in order to explore the optimal use of GFRP for strengthening the RC beams. The comparison is also made between the shear strength obtained from experimental results and that predicted from different design proposals available in the literature.