Two topics of practical significance are discussed : (a) The widely-held perception, reflected in nL\BB&
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus `?~pk)<C].
can be ignored in design to be on the safe side) is shown to be the result of a misconception 9HWtdJ+^C=
stemming from the shape of current design response acceleration spectra for soft/deep soil 'DVPx%p
conditions. Properly normalising the structural period by a dominant period of motion before x H\5T!
statistically processing recorded response spectral values, produces completely different shape and ! )ee{CwNc
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. =T9QmEBm
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic $LKniK
design of shallow foundations could overcome the strict limitations of the so-called “capacity mhh8<BI
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity T'FRnC^~
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– iQ :]1H s
nonlinear response may merely lead to acceptable permanent horizontal and rotational y6;A4p>
deformations.
