The built environment is increasingly exposed to structural and economic damage due to a variety of natural hazards, such as earthquakes, floods, landslides, debris flows, hurricanes, and tsunamis. In recent years, the intensification and increased frequency of some of these phenomena - driven by climate change - have emphasized the urgency of adopting a multi-risk approach. Nevertheless, the risk metrics commonly used for different hazards often lack comparability. As a foundational step toward a unified multi-risk assessment, the development of integrated, multilayer vulnerability frameworks is essential.

Italy, being one of the countries most affected by natural disasters, underscores the relevance of multidisciplinary strategies for modelling the vulnerability of the built environment. Among the most common structural typologies are reinforced concrete frame structures with brick infill panels. In this context, an analytical model was developed to characterize the out-of-plane capacity of infill masonry panels. The model reproduces a double arching mechanism across the wall thickness and follows an incremental displacement-controlled approach. This capacity model was integrated into a Monte Carlo simulation that accounts for the statistical variability of the geometric and mechanical properties of infill panels, categorized into representative classes. Moreover, the capacity curves generated by the model were compared with existing demand models from the literature to identify distinct damage states and derive the corresponding fragility curves.