Two topics of practical significance are discussed : (a) The widely-held perception, reflected in jYF3u0
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most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus iT"Itz-^#
can be ignored in design to be on the safe side) is shown to be the result of a misconception gk#rA/x
stemming from the shape of current design response acceleration spectra for soft/deep soil [ub\DL l
conditions. Properly normalising the structural period by a dominant period of motion before 9 JtG&^*
statistically processing recorded response spectral values, produces completely different shape and \nWpV7TSN
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. y^rg%RV
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic p'4P2
design of shallow foundations could overcome the strict limitations of the so-called “capacity #*/h*GNMs
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity 7KIQ)E'kG|
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– Z#O3s:`
nonlinear response may merely lead to acceptable permanent horizontal and rotational :[39g;V}c
deformations.
