Abstract:
The characterization of the dynamic behavior of an arch dam, and its evolution
throughout the structure's lifetime, provides important data for the safety
control process. Forced vibration tests remain a reliable technique for this purpose.
The Baixo Sabor dam is a 123 m high arch dam recently built in Portugal.
Forced vibration tests were performed before and after the reservoir filling.
Two techniques for forced vibration test are compared, discrete frequency
scanning, the standard methodology, and continuous frequency scanning (sine
sweep), a new proposed methodology, which allowed faster results without
loss of precision. For the interpretation of test results two numerical models of
the dam-reservoir-foundation system were built, and calibrated with the experimental
data. A good match of numerical and experimental results was
obtained for the six lowest frequencies and corresponding mode shapes.