Two topics of practical significance are discussed : (a) The widely-held perception, reflected in xwhS[ d
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus %(}%#-X
can be ignored in design to be on the safe side) is shown to be the result of a misconception ~rfUqM]I
stemming from the shape of current design response acceleration spectra for soft/deep soil As>-9 p>v
conditions. Properly normalising the structural period by a dominant period of motion before xoe/I[P]U
statistically processing recorded response spectral values, produces completely different shape and qu`F,O G
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. +T8h jOkC
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic r]3v.GZy
design of shallow foundations could overcome the strict limitations of the so-called “capacity ']C" 'b
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity 52P^0<Wq
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– xofx E4.
nonlinear response may merely lead to acceptable permanent horizontal and rotational >1*Dg?/=S
deformations.
