Software Development for Automatic Structural Health Monitoring of Cabril Dam

Cabril dam is a 132 m-high double curvature arch dam in Portugal. In operation for almost 70 years, the dam presents some signs of deterioration, including horizontal cracks along the upper part of the structure, which occurred during the first filling of the reservoir, and concrete swelling caused by alkali-aggregate reactions, detected in the 1980s. The dam was instrumented with a pioneering continuous vibrations monitoring system in 2008, designed to monitor the dynamic behavior under ambient/operational conditions and during seismic events, aiming to provide useful data for structural safety control. In recent years, the software component of the monitoring system was complemented with new programs for automatic data management, automatic detection of seismic vibrations, automatic modal identification, and comparison with finite element modeling results. This paper presents the latest addition to this software, a new automatic analysis program developed for structural health monitoring of Cabril dam. This program applies a methodology to detect structural modification based on the analysis of natural frequencies over time (global stiffness changes can be correlated with frequency values), and it also deals with automatic email sending, containing updated results for supporting dam performance assessment and informed management.