Derivation of vulnerability functions for European-type RC structures based on observational data

In this paper existing vulnerability relationships for reinforced concrete structures are reviewed with a view to their application to a European (and similar) seismic risk assessment scenario. New empirical fragility curves for reinforced concrete building populations are derived based on a data bank of 99 post-earthquake damage distributions observed in 19 earthquakes and concerning a total of 340 000 RC structures. The heterogeneous observational data are reinterpreted in terms of a new damage scale: homogenised reinforced concrete (HRC-scale), which is calibrated experimentally and allows a distinction to be made between the seismic resistances of different structural systems. The feasibility of using observation-based data for the generation of vulnerability curves for different strong ground motion parameters is investigated. The notion of developing a set of ‘homogeneous’ vulnerability relationships, applicable to different lateral-load resisting systems is explored and a series of relationships for different building height and age-classes are proposed. Large uncertainties are associated with the empirical relationships due to the nature and scarcity of observational data. The role of combined observation-testing-analysis as the basis for deriving reliable vulnerability formulations is thus emphasised. Notwithstanding, the statistics of the new vulnerability functions are a significant improvement over existing observation-based curves for European RC structures.