Diagnosis of the constructive pathologies of a masonry bridge: the case of the New Bridge of Ronda, Spain.

The eighteenth century New Bridge of Ronda in Spain is a monumental masonry structure spanning a 90 m deep gorge, representing a landmark of historic infrastructure and urban integration. While masonry bridges are renowned for durability, their preservation requires a deep understanding of the relationship between specific constructive logic and pathological degradation. This study adopts a multidisciplinary approach, combining historical constructive analysis with systematic visual inspection and structural pathological diagnosis. The research identifies and classifies primary damage mechanisms, linking cracking and deformation patterns to the structure's unique morphology and environmental interaction. Key findings reveal that the bridge's massive construction and internal lime based fills, combined with the permeability of the upper pavement, significantly influence water filtration and salt efflorescence, the main causes of deterioration in its walls and arches. Beyond a technical diagnosis, this work clarifies the methodological contribution to architectural heritage by bridging the gap between engineering diagnosis and conservation oriented design. By situating the New Bridge within the context of monumental masonry bridges, the study offers a transferable framework for the diagnostic assessment of historic infrastructure, providing a foundation for international research and future conservation practices.