An experimental and numerical investigation on torsional strengthening of solid and box-section RC beams using CFRP laminates

The issue of maintenance and repair/upgrading of existing structures has become a major issue, particularly extending the service lifespan of bridges. Fibre reinforced polymer (FRP) has shown great promise as a state-of-the-art material in flexural and shear strengthening as external reinforcement. However, little attention has been paid to torsional strengthening in terms of both experimental and numerical research. This paper reports the experimental work in an overall investigation of torsional strengthening of solid and box-section reinforced concrete beams with externally-bonded CFRP. This was found to be a viable method of torsional strengthening. Numerical work was carried out using non-linear finite element (FE) modelling. Good agreement in terms of torque–twist behaviour, steel and CFRP reinforcement responses, and crack patterns was achieved. The unique failure modes of all the specimens were modelled correctly as well.