Description and objectives

In the last few decades significant efforts have been done by the scientific community to develop fragility models representative of the existing building portfolio seismic response; these models are of paramount importance to guide government institutions and stakeholders in the seismic risk mitigation planning and in the decision-making process.

However, due to the complexity of the problem and the high number of variables involved in the performance assessment, fragility functions available in the literature, both for structures and non-structural elements, still require significant improvements. In most of the available literature, fragility curves for existing buildings are evaluated with reference to the as-built configuration, without considering that structural vulnerability is a time-variant issue due to two categories of phenomena: (1) progressive deterioration of material properties due to ageing, climate changes and to the exposure to aggressive environments (i.e. variation in relative humidity, and/or increase in carbon dioxide concentration), and (2) cumulative damage because of repeated overloading due to earthquake shocks.

The ERCULES Project focuses on existing Italian reinforced concrete critical facilities and it aims at developing state-dependent fragility functions taking into account the continuous evolution of material characteristics, the point-in-time overloads due to seismic actions and the damage level of non- structural elements (NSEs), a matter of primary importance in critical facilities given their role in emergency management.