Geoscience Reference
In-Depth Information
Acceptable Conf.
A46
(1.5, 4)
Low Conf.
1.8
A34-tr
B5
1.6
A1-tr
Veletsos and Nair
h/r = 1 to 2
~
T
T
A12-tr
1.4
A16-L
A44-L (nr)
A16-tr
Best fit, acceptable
confidence sites
1.2
A44-L (wt)
A17-tr
B14
A23
A2 (ot)
1.0
0.0
A21
0.1
0.2
0.3
0.4
1/
σ
= h/(V
s
*T)
Fig. 10.9. Soil-structure interaction period lengthening ratiofromrecorded earthquake
response of buildings (after Stewart et al.,2001). (The factor plotted on the horizontal
axis isthe height of the structuredivided bythe shear wave velocity of the soil
times thefirst mode period of the structure.)
fordesignarethejumpsbetweenthedifferentseismichazardcoefficientcurvesspecified
inEC8forvariousgroundtypes.Notsurprisingly,thisplacesapremiumongoodquality
site investigation beforedesign proceeds too far.
4. Spring models for shallow foundations on soil
A popular method for modelling soil-structure interaction is to represent the soil as a
bed of independent springs. It is well established that this provides valid modelling for
structural elements that are flexible in comparison to the medium which supports them.
One the other hand the model does not give valid soil-structure interaction modelling
