Two topics of practical significance are discussed : (a) The widely-held perception, reflected in ;RN8\re
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus ]UNZd/hIL
can be ignored in design to be on the safe side) is shown to be the result of a misconception .Gb +\E{M
stemming from the shape of current design response acceleration spectra for soft/deep soil <%bw /
conditions. Properly normalising the structural period by a dominant period of motion before GVd48 *
statistically processing recorded response spectral values, produces completely different shape and mog9 jw
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. *+lsZ8'^C
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic ;vO@m!h}U
design of shallow foundations could overcome the strict limitations of the so-called “capacity iRV ;Fks
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity \&A+s4c")
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– Ff"gadRXd
nonlinear response may merely lead to acceptable permanent horizontal and rotational w@]jpH;WX
deformations.
