Integrated Multi-sensor Monitoring and Finite Element Analysis of the Thermo-Mechanical Behavior of an Ageing Arch Dam

The average age of large dams, particularly in Europe and North America, now exceeds 50 years, raising increasing concerns over structural ageing and exposure to intensifying environmental conditions induced by climate change. Safeguarding their long-term performance requires advanced monitoring strategies integrated with reliable numerical modelling. The analysis combines an extensive multi-sensor monitoring system, including conventional instruments and distributed fiber optic sensing (DFOS), with a three-dimensional finite element (FE) model explicitly accounting for the dam geometry, block interfaces and surrounding geomorphological context. Monitoring data were used both for cross-validation between measurement systems and for calibration of the numerical model. DFOS measurements exhibited strong agreement with traditional sensors, with mean deviations of about 1 ℃ in temperature and 1 mm in displacement, confirming the reliability and enhanced spatial continuity of distributed measurements. The calibrated FE model reproduced the observed deformations accurately, enabling a refined interpretation of structural behavior in geometrically complex areas and under variable load conditions. Overall, the results demonstrate the effectiveness of integrating DFOS-based monitoring with numerical modelling for ageing dam assessment and provide a validated computational framework for simulating extreme environmental and reservoir scenarios.