The Effects of Localised Damage on the Structural Stability of Masonry Arches

Masonry arches represent a widely adopted structural solution in structure and infrastructure systems, including bridges, viaducts, and architectural constructions. They often exhibit signs of degradation due to ageing, insufficient maintenance, and exposure to natural actions, such as seismic events, soil settlements, and material deterioration. Such factors can significantly compromise structural stability, making the assessment and preservation process more complex. The present study investigates the stability of masonry arches subjected to horizontal loads, with particular attention to the influence of localised damage on the collapse multiplier across different geometric configurations. Arches with different geometry were analysed, ranging from elliptical arches with a quarter-span rise to semicircular (full-centre) arches. Damage was modelled by introducing localised reductions in thickness along the entire intrados to evaluate its impact on the structural response. Moreover, multiple thicknesses were considered for each geometry to assess slenderness's role in undamaged and damaged conditions. The findings identify the most critical damage locations regarding structural capacity loss under the applied loading configuration and provide useful insights for the preliminary assessment and conservation of historic masonry arch structures, particularly in contexts where rapid and simplified evaluations are required.