Effect of fire on FRP reinforced concrete members

Fire resistance of concrete members reinforced with fiber reinforced polymer (FRP) rebars is an extremely crucial area that needs to be investigated prior to implementing FRP composite materials in buildings and other fire vulnerable structures. This work examines analytically the performance of FRP reinforced concrete beams subjected to high temperatures. Methods for estimating the residual flexural and shear strengths of FRP reinforced concrete beams exposed to fire for a certain duration of time were developed. The proposed methods are based on the assessment of the reduction in the initial strengths of concrete and FRP reinforcement resulting from the high temperatures developed inside the beam. A parametric study was carried out to study the effect of concrete cover, fire exposure time on the FRP temperatures and shear and flexural capacities of reinforced beams. It was found that the FRP temperatures decrease with increasing the concrete cover, and FRP reinforced concrete beams exhibited significant degradation in shear and flexural strengths. Finally, this study recommends a minimum concrete cover for fire resistance of 64 mm (2.5 in.) for FRP reinforced concrete.