HYSTERETIC DAMPING OF SANDS UNDER CYCLIC LOADING AND ITS RELATION TO SHEAR MODULUS

Abstract

Comprehensive tests were performed to obtain hysteretic dampings of normally consolidated reconstituted sands with use of a resonant-column apparatus and a static torsional shear device. It is shown that there is a simple relationship between the ratio of shear modulus to the shear modulus at very small strain level and damping ratio for sands tested. This relationship is not affected considerably by void ratio and confining pressure for shear strain amplitude from 10^-6 to 10^-2. For a given value of G/{G}_γ=10^-6; the ratio of shear modulus to that at γ=10^-6, the values of damping ratio of clean sands tested are slightly larger than those of other reconstituted natural sands. For these two kinds of sand, average curves representing the relationship between damping ratio and G/{G}_γ=10^-6 are shown.These curves can be used for design purposes to evaluate damping ratio of sands from the value of G/{G}_r=10^-6.