An investigation on fire performance of FRP strengthened R/C Beams

As the use of Fibre-Reinforced Polymer (FRP) materials continues to expand into the structural repair market, concerns over the performance of these materials in fire conditions are now at the forefront of research. While externally bonded FRP sheets have been shown to successfully enhance the flexural and shear capacity of bridges and other structures, their application in interior spaces, where fire is a significant concern, remains questionable in light of these materials' comparatively poor resistance to elevated temperatures. This paper presents the results of an ongoing study to document the performance of FRP-strengthened reinforced concrete beam-slabs exposed to fire. With such experimental results, fireproofing materials have the potential to earn standard performance ratings, which are essential to the design engineer and necessary for the continued increase of FRP applications worldwide. A brief synopsis of existing literature related to FRP behaviour at high temperature is provided, in addition to a review of the current fire endurance criteria for structural members. Two large-scale concrete beam-slab assemblies were strengthened with FRP sheets and protected with a two-part patented fire insulation system. The results of fire tests performed on these specimens are presented herein, with emphasis placed on the temperatures measured in the specimens during fire exposure. The data obtained from the tests served to validate a numerical heat transfer model, which predicts the temperature within a strengthened and insulated reinforced concrete beam-slab assembly. Test results and model data indicate that appropriately designed and insulated FRP-strengthened beam-slab assemblies can achieve fire endurances of four hours or more.