Response behaviour of reinforced concrete beams strengthened in shear with FRP

Abstract

In this paper an analytical model, able to predict the shear-displacement response of slender RC beams reinforced in shear with FRP, is presented. It allows to evaluate the complete strain and stress fields, for each load step, on the basis of the MCFT framework. The key role of the effective strain of FRP reinforcement at failure has been investigated. At the same time, the interaction FRP-steel stirrups has been taken into account by introducing an appropriate factor. It is able to reproduce the decrease of stirrups stress level when an external reinforcement is used. The proposed model has been validate against a database of specimens collected in literature. Results have shown the remarkable capacity of the presented formulation to reproduce the response behaviour of RC beams strengthening in shear with FRP.