Two topics of practical significance are discussed : (a) The widely-held perception, reflected in n% ; wQ^
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus C?@vB M}
can be ignored in design to be on the safe side) is shown to be the result of a misconception X`km\\ *
stemming from the shape of current design response acceleration spectra for soft/deep soil /BB(riG
conditions. Properly normalising the structural period by a dominant period of motion before )N[9r{3
statistically processing recorded response spectral values, produces completely different shape and _t<&#D~
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. R<$_
<z
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic uq<k T [
design of shallow foundations could overcome the strict limitations of the so-called “capacity +`pS 7d
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity OiI [w8
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– D<}z7W-
nonlinear response may merely lead to acceptable permanent horizontal and rotational &u5OL?>
deformations.
