Two topics of practical significance are discussed : (a) The widely-held perception, reflected in v#FJ+
most seismic codes, that soil-structure interaction (SSI) plays invariably a beneficial role ( and thus 4?P%M"\Iv
can be ignored in design to be on the safe side) is shown to be the result of a misconception CF4O h-f
stemming from the shape of current design response acceleration spectra for soft/deep soil _WRR
3
conditions. Properly normalising the structural period by a dominant period of motion before "z{_hp{T^
statistically processing recorded response spectral values, produces completely different shape and GFASF,+
size of spectral ordinates ; thus an increased period due to SSI may lead to higher response. INN/VDsJ
(b) Analytical, experimental and field evidence in recent years has started revealing that seismic doxdRYKL
design of shallow foundations could overcome the strict limitations of the so-called “capacity | o ; j0
design”, by allowing significant sliding, uplifting, and even mobilisation of bearing–capacity c %xED%X9
failure mechanisms to occur. It is shown that under seismic conditions such dynamic inelastic– }QX 2 :a
nonlinear response may merely lead to acceptable permanent horizontal and rotational $M}k%Z
deformations.
