Shear Code Provisions Applied to the Prediction of FRP Strengthened Prestressed I-Girders

Shear strength contribution of concrete, steel and FRP in case of strengthened prestressed I-girders is not well defined in the literature. Analytical design and prediction models give a lot of variation compared to the experimental observations. The suitability and effectiveness of analytical models in case of strengthened prestressed I-girders is an open research question. This paper compares the shear strength prediction based on the analytical models given in different codes or guidelines, when applied to FRP strengthened prestressed I-girders. This is benchmarked against a small experimental dataset taken from literature. It is concluded that the available design guidelines are not able to predict the shear strength of FRP strengthened prestressed I-girders. FRP shear contribution models derived for rectangular cross sections fail to capture the phenomenon of early debonding around the internal angles of the I-section and cannot be used for complex sectional geometries. The results reported in this paper are part of a wider study to investigate anchored FRP shear strengthening configurations, to avoid local de-bonding at the concave zones of complex cross-sections such as I-girders.