Provisions of fire resistance is one of the key considerations in building design since fire represents most severe hazard experienced by built infrastructure during their life time. Current fire resistance provisions do not account for critical factors in evaluating fire resistance of reinforced concrete (RC) members and hence are not applicable for realistic fire performance assessment of RC members. Rational design approaches for evaluating realistic fire resistance of RC members can be achieved through the use of time equivalency. Existing time equivalency methods have a number of limitations and are derived for protected steel members and may not be applicable for RC members.

This thesis presents the development of an energy based approach for evaluating time equivalent of RC members under realistic fire scenarios. To generate large amount of data required for development of energy based method, a macroscopic finite element model has been extended to cover beams with T and I cross-sections. The validated numerical model is used to undertake a set of parametric studies on RC beams. Data from the parametric studies is used for validating the proposed energy based approach. Regression analysis has been applied to the data set and a correlation between the ratio of time equivalent predicted by the finite element model and equal energy method has been established. Based on the results, it is shown that the proposed energy based approach provides a better estimate of time equivalent for RC beams than current approaches.