Two topics of practical significance are discussed : (a) The widely-held perception, reflected in z+wBZn{0I
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus " $m3x O
can be ignored in design to be on the safe side) is shown to be the result of a misconception "*TnkFTR
stemming from the shape of current design response acceleration spectra for soft/deep soil TNiF l hq
conditions. Properly normalising the structural period by a dominant period of motion before k.0$~juu
statistically processing recorded response spectral values, produces completely different shape and u6|7P<HUfb
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. -<CBxyZa&
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic HgG"9WBe%
design of shallow foundations could overcome the strict limitations of the so-called “capacity 1k
"*@Z<
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity sd#a_
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– ukhI'alS,
nonlinear response may merely lead to acceptable permanent horizontal and rotational h`jtmhoz
deformations.
