Shear strength assessment of FRP pre-tensioned concrete beams

The low susceptibility to corrosion of fiber reinforced composite materials (FRP) has led to considering their use for prestressing reinforcement, as an alternative to steel. However, the effects of FRP fragility, low elastic modulus, and low bond with concrete, when compared to usual prestressing steel, must be accounted for in the design of structures. This paper presents a theoretical model for predicting the shear strength of FRP prestressed pre-tensioned concrete beams, extending a previously developed model (CCCM), to account for the properties of FRP as active reinforcement, and to capture reductions in shear strength caused by bond loss in the FRP tendons. The model has been validated by comparing the theoretical predictions with the results of shear tests available in the literature. Good accuracy has been obtained in predicting the shear capacity and also in identifying those cases where shear failure is associated to loss of anchorage bond.
The study presented in this paper was developed in the scope of research projects RTI2018-097314-B-C21 and PID2021-123701OB-C21 funded by the Spanish Ministry of Science and Innovation and the European Regional Development Funds (ERDF).
Postprint (published version)