Multilevel optimization strategy for enhancing seismic safety and energy performance in school building portfolios

This study addresses two critical gaps in current seismic risk mitigation practices for school infrastructure. First, it introduces a safety-oriented, multi-level decision-making framework that systematically integrates structural safety, cost-efficiency, and implementation feasibility into a unified methodology. Unlike conventional approaches that often treat safety as one of several competing objectives, the proposed framework enforces life-safety as a non-negotiable constraint throughout the prioritization process. This emphasis emerges directly from stakeholder engagement. Second, the study fills an important scale-related gap by operationalizing risk assessment and intervention planning at the portfolio level. In doing so, it provides a crucial link between territorial-scale assessments and building-specific evaluations. Applying the framework to a portfolio of Italian school buildings shows its effectiveness, with results revealing strong variability in risk metrics and confirming that factors like the number of stories and construction period significantly influence both safety and loss. Retrofit cost-effectiveness is shown to depend strongly on initial building conditions, with older and more vulnerable structures delivering greater safety gains per unit of investment. Although energy retrofits were analyzed separately, findings suggest that standalone energy upgrades offer limited financial viability, reinforcing the value of integrated seismic-energy strategies.