PSI - Issue 78

Livio Pedone et al. / Procedia Structural Integrity 78 (2026) 1991–1998

1992

1. Background and motivation The definition and implementation of effective strategies for seismic risk management and mitigation is nowadays recognized as an urgent need in many seismic-prone countries worldwide. Reducing seismic risk requires taking action at all scales, from global to local, possibly through a medium-to-long-term national plan (e.g., Pampanin, 2017). In this context, a Detailed Seismic Assessment (DSA) of the built environment plays a crucial role, as it can support informed decision-making and the development of a national prioritization plan. In the last decades, significant research has focused on developing supporting tools for assessing seismic risk at a large scale. State-of-the-art procedures rely on probabilistic frameworks, involving: i) a probabilistic model for seismic hazard, ii) an exposure dataset (typically in the form of statistical data), and iii) a set of fragility/vulnerability relationships to express building- level damage or losses (e.g., D’Ayala et al., 2014). The results are typically provided as decision metrics of major interest for end-users and stakeholders, such as casualties or economic losses, and are visualized through seismic risk maps (e.g., the Italian last National Risk Assessment; Dolce et al., 2021). These maps provide valuable support in the management of seismic risk at a large scale. However, as previously mentioned, their exposure dataset typically employs aggregated statistical data, rather than information on individual buildings. Ideally, a national risk map could be carried out from the aggregation of the results at the urban scale level, which should employ a more detailed building-by-building vulnerability and risk assessment. However, such a comprehensive assessment procedure involves some main challenges: i) a lack of structured and complete geospatial-based data on the building environment; ii) the complexity of properly considering the interconnection and the interactions among different infrastructural systems part of the construction environment (e.g., building stock, road network, water and gas pipelines), and iii) the development of an ad-hoc, standardized, and interoperable platform for risk management, which would require huge storage and computational power. To overcome the issue of limited building knowledge at a large scale, recent research considered Geographic Information System (GIS), available from multiple open-source projects and government endeavors. Due to the limited building knowledge at this scale of analysis, available methodologies for seismic risk assessment typically employ a “simulated design” procedure, with a consequent seismic vulnerability assessment performed through either analytical/mechanical procedures (e.g., Del Gaudio et al., 2015) or numerical (software-based) simulations (e.g., Ruggeri et al., 2022). Moreover, other studies investigated a paradigmatic shift towards large numerical simulations of entire urban areas, referred to as Integrated Earthquake Simulations (IES; e.g., Lu et al., 2020). IES consists of non-linear dynamic (time-history) analyses on simplified multi-degree-of-freedom (MDoF) models for the entire urban area, typically defined from GIS data and empirical relationships. Concerning urban areas, although significant effort has been devoted in the past decades to the collection of fragility and vulnerability models for specific assets (e.g., HAZUS methodology; Kircher et al., 2006), only a smaller proportion of research investigated the seismic performance of spatially distributed systems (Franchin, 2018) such as road networks, power networks, gas pipelines, or water distribution networks. Finally, a refined seismic risk assessment at the urban level should be based on a comprehensive model of urban environments, including both buildings and interconnected infrastructural systems (Franchin, 2018). In Europe, a significant contribution toward this goal has been provided by the SYNER-G project (Pitilakis et al., 2014), where a general framework has been developed for the analysis of a set of interconnected civil infrastructural systems (Franchin, 2014). In line with the above discussion, as a part of a wider PNRR (National Recovery and Resilience Plan) - National Research Centre (CN1) research project on HPC, Big Data and Quantum Computing (e.g., Pampanin et al., 2025), this paper proposes an innovative framework for seismic risk and loss assessment of urban areas, based on a multi scale, multi-refinement approach. The paper is structured as follows: Section 2 describes the proposed methodology; Section 3 presents an illustrative application for a virtual urban area; finally, conclusions are given in Section 4. 2. Framework for seismic loss assessment of urban areas The proposed methodology for seismic loss assessment of urban areas is shown in Fig. 1. Urban areas are herein defined as a “macro - system” composed of several interconnected layers; at the scale of interest, single elements/assets such as buildings, water pipelines, or strategic structures are only components (e.g., Franchin, 2018).