Application of expert judgment to the quantification of a damage scale for reinforced concrete buildings exposed to fire

Essential in the fire fragility assessment of mid-rise reinforced concrete buildings is a relevant damage scale. This study adopts expert elicitation to construct a damage scale relevant to the slabs of these buildings by relating thresholds of four structural response measures (i.e., spalling, residual capacity, peak rebar temperature and deflection) to three qualitatively described damage states of increasing severity. The opinions of thirteen international experts are pooled together using Cooke's Classical Model, which recognizes that uncertainty exists around each damage state threshold and seeks to quantify it. Compared to an approach which weights exert opinions equally, this Model results, in most cases, in conservative estimates of the damage state thresholds associated with well-constrained uncertainty. Areas where more research is needed are also identified. These areas include the determination of the thresholds of the first three measures when the extensively damaged slab cannot be repaired, and of the residual capacity of any of the three considered damage states.