882
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
lower stresses are distributed in the outer areas. The
measurements under these foundations with a thickness of 0.40
m (raft 1) respectively 0.50 m (raft 2) indicate a flexible
behaviour of this particular footing.
Figure 12: Measurements of the pressure pads 6, 7, 13 and 17 at
and the results of the centrifuge model
tests. A flexible behaviour (as expected by the definition of DIN
d.
eld for future research, where the interaction of
the whole building-structure with the soil should be
are also
most grateful to Pierre Lehmann and Sandra Kümin (CES Ltd.)
Huwiler & Portmann Ltd.) who made the
Arn
Arn
Arn
Kan
Lau
Lau
Sch
Spr
Modelling in Geotechnical
Engineering
, Balkema, 113-118.
inkler, E. 1867.
Die Lehre von der Elastizität und Festigkeit.
Domenicus. Prag.
Zimmermann, H. 1888.
Die Berechnung des Eisenbahn-Oberbaues.
Verlag Wilhelm Ernst & Sohn. Berlin.
Merenschwand (Arnold, 2012).
6 COMPARISON OF THE RESULTS
There is a clear difference between the two measured
foundation systems (Alpnach & Merenschwand) concerning the
stress distribution between foundation and adjacent soil. The
bending moment in the girder originating from the loads of the
4 storey building is dominating the stress distribution at the
building in Alpnach. It is passed from the supporting girder to
the column and further down to the foundation. This bending
moment can be verified by the measurements of the strain gages
and allow the construction process to be followed. The moment
clearly dominates the stress distribution while a stiff behaviour
can be noticed.
Little bending moment is passed from the earth-fill
supporting roof to the foundation at the building in
Merenschwand. Therefore the stress distribution here can be
more easily compared to the ideal situation assumed with some
of the simplified models
4018) can be identifie
7 CONCLUSION
The full scale measurements show a clear influence of the
loading situation to the stress distribution between raft and
adjacent soil. Bending moments are passed from roofs via
columns and walls to the foundations where they influence the
soil-structure interaction by changing the stress distribution
between structure and adjacent soil. The so found influence of
the loading situation to the stress distribution could not be
shown in the centrifuge tests where the ideal test conditions
without bending moments have been studied. The system-
stiffness equation is only valid for this type of “ideal” loading
situations, where bending moments in the structure do not play
a significant role. Bending moments among other parameters
like e.g. inhomogeneous design of a foundation do influence
this stress distribution. Thus a single value of system stiffness
for the whole foundation can be misleading as the stress
dependency of the modulus of the ground is not taken into
account but will have for rafts an influence on the design. This
opens a new fi
investigated.
8 ACKNOWLEDGEMENTS
The authors are most grateful to the ETH-Grant (TH21 07-2)
which made the presented investigation possible. A special
thank goes to Markus Iten who conducted all the centrifuge tests
and to Ernst Bleiker who was responsible of the measurement
systems in Alpnach and Merenschwand. The authors
and Sepp Portmann (
full scale measurements possible by providing the construction
sites for the installation of the measurement systems.
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