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cross-link density in any point of the items,
especially for isolators with big dimensions.
Another important parameter that will be
investigate is the hysteresis loss and thermo-
mechanical behavior that, as known, can be
correlated to the dynamic behavior based on cross-
link structures. Finally, it will be considered the
aging or the stability of the rubber items, that in
general depends on the structure of the elastomer
used. In our theoretical work it is shown that a
proper calculation is needed when a product
involves a large volume of the rubber items in the
seismic isolators. It is suggested to consider the
following steps for a choice of the optimal thickness
of the pads as a function of predetermined hardness,
which also allows to increase the volume of rubber
and decrease the number of the steel plates:
1) Calculation of the Young’s modulus from
hardness.
2) Calculation of the maximum vertical stiffness
supported.
3) Determination of the stretch-stress behaviour
of the single rubber pad.
4) Determination of the shear behaviour of the
whole isolator under large deformations.
5) Utilization of the stretch-stress and the shear
behaviour in order to define the best solution for a
single building.
6) Combination of the technical characteristics
of the rubber pads and the steel laminas to minimize
the cost, in order to introduce the seismic isolation
technology in large buildings in high seismicity
countries. The authors are convinced that this
approach could be in the future the normal routine to
design new buildings.
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