PSI - Issue 66

Umberto De Maio et al. / Procedia Structural Integrity 66 (2024) 486–494 Author name / Structural Integrity Procedia 00 (2025) 000–000

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1. Introduction Flash floods represent one of the most catastrophic natural hazards, with profound consequences on both human life and built environments. Particularly devastating in mountainous regions, these rapid-onset events have led to significant loss of life, extensive damage to structures and infrastructures, and substantial economic costs throughout history. Recent studies (Antoci et al., 2007; Kvočka et al., 2016; Zhang et al., 2020) emphasize that flash floods are increasingly recognized as a growing threat due to factors such as climate change, unplanned urbanization, inadequate watershed management, and heightened socio-economic activities. As a result, the frequency and intensity of these events are expected to increase, contributing to even more unpredictable and severe outcomes in the future (Jonkman, 2005; Anghileri et al., 2005). Given this alarming scenario, it is crucial to enhance our understanding of how flash floods impact structural integrity, particularly in masonry constructions, which are prevalent in many vulnerable regions. As a matter of fact, masonry structures, known for their historical and architectural significance, are especially susceptible to damage caused by hydrodynamic forces and sediment impacts during such events (Aly and Asai, 2014; Ataei and Padgett, 2015; Chen and Christensen, 2017; Fang et al., 2021). Over the past decade, significant research efforts have been dedicated to assessing the vulnerability of masonry structures to flooding events, resulting in the development of accurate models based on both empirical and physical approaches. Statistical and indicator-based methods are widely accepted due to their simplicity and ability to provide a clear spatial representation of vulnerability (Nasiri et al., 2016; Papathoma-Köhle et al., 2017). Moreover, probabilistic frameworks for masonry damage and failure risk under flood hazards at urban scale are proposed in (Mebarki et al., 2012) which combines the effects of several governing parameters with individual weighted contribution such as material quality and geometry, presence and distance between columns, beams, openings, resistance of the soil and its slope. These methods offer a straightforward process for assessing potential risks and are favored for their capacity to depict vulnerability across different regions. However, a notable limitation of these approaches lies in their dependence on the quality and quantity of available empirical data. The accuracy and reliability of the assessment are inherently tied to the comprehensiveness of the data used, meaning that incomplete or low-quality datasets can significantly undermine the effectiveness of the vulnerability analysis. Consequently, while these methods offer clear advantages in terms of ease of use and spatial clarity, their robustness is compromised when empirical data is lacking or insufficient. A more consistent evaluation of the structural vulnerability is predicted by physically based numerical and analytical models, able to assess the structural integrity and failure mechanisms of the building under flooding by using the well-known damage models. For example, in (Fang et al., 2021) a nonlinear numerical approach, based on an advanced Structured Arbitrary Lagrangian-Eulerian (S-ALE) solver, has been proposed to investigate the mechanics of the fluid-structure interaction. The physical vulnerability of building has been quantified through a macroscopic damage index, i.e., the lateral drift ratio of the ground floor. The synergistic combination of the Material Point Method (MPM) and the Arbitrary Lagrangian-Eulerian (ALE) approach has been successfully employed in (Luo et al., 2020) to study dynamic interaction problems and assess landslide debris mobility as well as the response of structures under debris impact. Similarly, in (Lonetti and Maletta, 2018) the effects of floods on masonry structures, in terms of damage phenomena and collapse mechanisms, are investigated by using a comprehensive numerical approach simulating the fluid–structure interaction based on the synergic work of the ALE formulation, the two-phase fluid flow, and the finite-element structural modelling based on a fracture approach (De Maio et al., 2024a, 2024b). In (Li et al., 2018), a parametric study of the influence of the fiber reinforcement arrangement as well as the types of the FRP material on the structural response of masonry buildings is performed by using an anisotropic brittle damage model for the masonry material. As a matter of fact, FRP-strengthened masonry and concrete structures are usually investigated with different model based on damage and cohesive fracture approaches in order to develop practical methods to prevent the catastrophic brittle failure (Bruno et al., 2007; De Maio et al., 2023b, 2023a). Similar approaches are employed to analyze delamination phenomena in layered composite materials using both ALE formulation and fracture mechanics in (Funari et al., 2018; Greco et al., 2015). In (Mazzorana et al., 2014) an interesting method to assess vulnerability by providing a detailed spatial and temporal representation of the impacting hazard is proposed. This is followed by analyzing the geometry of the building in relation to the time-varying flow field and soil bearing capacity to quantify impacts and potential intrusion pathways.