Page 116 - Çevre Şehir İklim İngilizce - Sayı 4

Seismic Isolation in Earthquake -
Resistant Structural Design for Resilient Cities

moves on the insulation system just like a rigid box (Skinner, Robinson
and McVerry, 1993; Naeim and Kelly, 1999; Chen, Jiang and Lou, 2008).
The structural and non-structural elements are protected from the harmful
effects of earthquake as a result of the integrity of the superstructure due
to the reduced relative storey drifts as a result of applying the seismic
isolation; on the other hand, the content of the building is also preserved
from these effects due to the reduced floor accelerations.
According to TBDY (2018), for a building to be newly constructed with
seismic isolation and for residential purposes, normal performance target
in the design earthquake ground motion level (DD-2) is “Limited Damage”
in other words “ that a limited damage occurs on the building load-bearing
system components, namely, the nonlinear behaviour remains limited”. Even,
for the buildings with seismic isolation with purpose of use as a hospital,
school, dormitory, etc., at the design earthquake ground movement level
(DD-2) “Uninterrupted Use” in other words “the situation where structural
damage has not occurred to the building load-bearing system components
or the damage remains negligible” is targeted.
In this study, the definition of seismic isolation is made, seismic isolation
applications are explained, and the modeling of a sample seismically isolated
building and its behavior under near-fault, vertical earthquake effects are
discussed.

1. Seismic Isolation Philosophy and Literature

The main elements that should be available in a seismic isolation system
can be listed as: (1) Extension of the construction period due to horizontally
flexible insulators.
(2) Keeping the isolation system displacements at reasonable levels as
well as absorbing the earthquake energy transferred to the structure at the
isolation system level thanks to the isolators with damping properties and the
use of additional dampers. (3) Using the isolators with initially high horizontal
rigidity, but, which decreases by several times when a certain displacement
is exceeded in order to avoid frequent movement of isolation systems under
minor earthquakes and wind loads. (4) Re-centering feature to prevent
permanent displacement. (5) Using isolators with high vertical rigidity to
transfer the high vertical loads safely. (6) Ensuring the stability in the isolators
despite major horizontal displacements. The greatest advantage of seismic
isolation is that it protects both the structure itself and its contents and non-
structural wall and façade elements from the harmful effects of an earthquake
at the same time. This is achieved by decreasing floor accelerations due to the

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