Vulnerability assessment of historical cities including SSI and site-effects

Risk assessment of historical cities is commonly addressed considering a portfolio of fixed-base structures, i.e., neglecting the interaction between soil, foundation, and structure (SSI). The state-of-the-art literature proves that neglecting SSI and site-effects may lead to inaccurate risk estimates by a substantial margin. Including these effects on the city-scale vulnerability analysis of historical sites is considered challenging due to the cultural and historical importance, high exposure concentration, and complexity of the whole interacting system. To this aim, a new methodology is proposed to calculate fragility functions of masonry structures considering SSI and local site-effects, suitable for large-scale applications. The applicability of the proposed approach is based on globally available data regarding soil, foundation, and building taxonomy. This study encourages engineers, practitioners, and risk analysts to include SSI and site-effects for an accurate assessment of seismic safety of existing buildings in historical centers to identify the most appropriate short- and long-term earthquake mitigation policies