Two topics of practical significance are discussed : (a) The widely-held perception, reflected in (fhb0i-
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus 4V"E8rUL(
can be ignored in design to be on the safe side) is shown to be the result of a misconception s2a {>II6
stemming from the shape of current design response acceleration spectra for soft/deep soil 3 #n_?-
conditions. Properly normalising the structural period by a dominant period of motion before n. }Zk G0`
statistically processing recorded response spectral values, produces completely different shape and O"+ gQXe
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. 7RQR) DG
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic ,=uD ^n:
design of shallow foundations could overcome the strict limitations of the so-called “capacity SjK
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity K,tQ!kk
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– !K#qe Y}
nonlinear response may merely lead to acceptable permanent horizontal and rotational PioZIb/{
deformations.
