Vibrational Transfer from Shear Buildings to Ground

A plausible, simple mechanism is presented to illustrate vibratory energy transfer from a shear type building to the ground on which it stands. The mechanism involves wave travel and reflection constants. Because the simplified mechanism fails to consider some geometrical continuity requirements, notably near the interface perimeter, a modified method for circumventing this defect is presented. The radiation loss of vibratory energy from a building is related to that of a pseudo-damping phenomenon involving stepwise, half cycle decreases in vibrational amplitudes. An illustrative example shows that the unmodified pseudo-damping is remarkably large unless the ground is either hard or soft; both conditions lead to instability. The suggested method of modifying the interface area yields pseudo-damping values that appear to be of reasonable magnitude.