Thermal behavior of concrete slabs reinforced with FRP bars in case of fire: experimental investigation and numerical simulation

The use of Fiber Reinforced Polymers (FRP ) reinforcing bars or grids instead of the traditional steel reinforcements represen ts nowadays an intere sting application, above all in order to improve the structural durab ility and the actual life expectancy. Several building codes allow concrete structures reinforced with FRP are designed but no calculation model taking account of fire condition is available. Key-aspect of the structural behavior of concrete slabs reinforced with FRP bars is the large reduction of both resistan ce and stiffness due to high temperatures. Such issue is shown by experimental and numerical results reported in literature. Six concrete slabs reinforced with Glass FRP bars characterized by different values of concrete cover and anchorage length were recently tested in fire condition. A comprehensive description of the exp erimental program and some meaningful experimental results are repor ted in a companion paper. In the present paper a detailed analysis of thermal readings is reported. The importance of both concrete co ver in the zone directly exposed to fire and anchorage length of the FRP bars in the unexposed one has been showed. Finally, thermal behavior of concrete slabs tested in furna ce has been simulated by means of numerical models: results showed a good agreemen t with experimental outcomes.