Abstract Summary
In Cahora Bassa dam, a 170m-high arch dam located in western Mozambique, a system for vibrations monitoring of the type SSHM (Seismic and Structural Health Monitoring) was installed in 2010. The dam, in operation since 1974, is affected by a swelling process of small/medium amplitude. Aiming to control its structural health over time, the dam was instrumented with the referred SSHM system which includes 10 uniaxial accelerometers in the crest gallery and 3 triaxial accelerometers in the dam-foundation interface. The latest results on the dynamic behaviour monitoring of the dam are presented, namely the evolution of the main natural frequencies over time and the corresponding mode shapes. Using HST statistical models for separation of effects, the evolution of frequencies over the last 12 years is analyzed in order to detect a possible global stiffness decrease induced by the swelling process. A comparison is made between HST results and numerical results from a 3DFE model of the dam-reservoir-foundation system.
