Assessment of reinforced concrete slabs post-fire performance

An analytical study is presented of the post-fire structural performance of one-way RC solid slabs that have been cooled off from various scenarios of fire events. Three possible fire scenarios were considered for a mid-span section: Fire below or above the slab and a simultaneous fire above and below it. According to the fire scenario and duration, the profile along the slab cross-section's height of the temperatures, from which the slab has cooled off, is calculated. Then, existing models of the residual constitutive relations of the steel and of the concrete are applied in cross-sectional moment-curvature analyses. The results are presented and analyzed in terms of the residual moment-curvature curves and two non-dimensional ratios, which are indicative of the residual moment capacity and ductility. It is noted that the residual deformation capacity, indicated by the latter ductility ratio, has been rarely examined in studies that deal with the residual, post-fire performance of RC members. Findings of this study show that evaluation of the post-fire load bearing capacity may not be enough in order to assess its performance. They clearly indicate that the possibility of decrease of its ductility due to the exposure to fire needs to be assessed as well.