ABSTRACT
This paper presents finite element (FE) modeling of unprotected/insulated FRP-strengthened RC beams subjected to standard fire exposure. In the FE model, the temperature-dependent properties of concrete, steel and FRP as well as the FRP-to-concrete and the steel-to-concrete interfaces are properly considered. Comparisons between the FE predictions and the existing test data are presented to demonstrate the accuracy of the proposed FE model. Further parametric analyses revealed that, unless a very thick insulation layer is used (i.e., usually an impractical solution), the critical role of the insulation layer in FRP-strengthened RC beams is to protect the original RC beams by delaying the temperature increase of the internal steel reinforcement rather than to protect the FRP strengthening system. Therefore, the fire performance design of an insulated FRP-strengthened RC beam can be conservatively and closely approximated by that of an insulated un-strengthened RC beam.
