Optimal isolation of structures from the external vibrations by particulate media Hasson Tavossi, Department of Engineering Technology, Savannah State University, 3219 College St. Savannah, GA 31404.

Absorption of ground-borne vibrations by aggregate of particulate is investigated to determine attenuation versus frequency and material properties. The goal is to mitigate transmission of vibrations from the ground into the building structures. Attenuation depends on mechanical properties of the particulates medium, such as; elastic moduli, contact areas, aggregate size-distribution, and degree of compactness. Experimental findings show that aggregate material behaves as a band-pass filter for vibrations transmitted through them. Some aggregate materials have a frequency band-gap where frequencies in a certain range are strongly attenuated. Media of uniform size particulates are subjected to mechanical vibrations at different frequencies and amplitudes. Vibration attenuation versus frequency is measured as a function of material thickness, aggregate size, and compactness. The results can provide the characteristics of optimal dampers for external vibrations transmitted into the building structures.