Rational Approach for Evaluating Fire Resistance of FRP Strengthened Concrete Beams
AbstractThis paper presents a rational approach for evaluating the fire resistance of reinforced concrete (RC) beams strengthened with different types of fiber reinforced polymers (FRP) This approach is based on conventional fire design principles for RC beams, but incorporates the contribution of FRP and fire insulation in fire resistance calculations. Simplified equations are proposed for evaluating cross sectional temperatures in fire exposed FRP strengthened RC beams with and without fire insulation. These temperatures are used to determine the loss of strength in steel, FRP, and concrete using temperature dependent strength properties. Employing the strength in different materials, the moment capacity of FRP strengthened beams is calculated, at any given fire exposure time, by applying force equilibrium and strain compatibility principles. At each time step, the limit state is applied to define the failure of an FRP strengthened RC beam, and the time to failure is taken as the fire resistance of the.