Infrasound Assessment of the Roller Compacted Concrete Dam: Case Study of the Portugues Dam in Ponce, PRH. Diaz-Alvarez , V. P. Chiarito , S. McComas , M. H. McKenna ,
 U.S. Army Engineer Research and Development Center, Vicksburg, MS, USA
The U.S. Army Corps of Engineers is currently investigating the use of infrasound sensors to monitor the health of structures of interest. Infrasound is low-frequency (2-20 Hz) acoustic energy and is capable of propagating many kilometers from the source structure. Large infrastructure, such as dams, bridges, and buildings emit such signals at their natural or driven frequencies of vibration, providing an indication of the structural condition.
Field investigations have been completed at the Portugues Dam, in Ponce, Puerto Rico. A cold-gas-thruster (CGT) was used to induce broadband, transient behavior in the dam-foundation-reservoir system. A dynamic analysis of the RCC dam was conducted in COMSOL Multiphysics® software to calculate the eigenfrequencies of the dam and to study the mode shapes of the dam.