Page 126 - Çevre Şehir İklim İngilizce - Sayı 4

Seismic Isolation in Earthquake -
Resistant Structural Design for Resilient Cities

TGUA-1 and TGUA-2 certificates who have special expertise in these areas
for the implementation of Site-Specific Earthquake Hazard Analyses, the
Identification of Earthquake Ground Motions in the Field of Time History,
Site-Specific Soil Behavior Analyses, Structure Pile Soil interaction analyses. In
accordance with the TBDY (2018) rules, the main aspects to be considered in
the design can be summarized as follows:
1. TBDY (2018) includes only rubber and curved surface friction pendulum
isolators. Other types of insulators are excluded from the scope. In
addition, there are no design rules yet in the regulation for cases where
additional dampers are required to be used.
2. The performance targets of buildings with seismic isolators are
different from those of fixed-base buildings. The insulation system is
designed for Continuous Use (KK) performance target independent of
Earthquake Design Class (DTS), while the superstructure is designed
for normal performance target of Limited Damage (SH) for DTS=1, 2,
3, 3a, 4, 4a structures and for advanced performance target of KK in
DTS=1a, 2a structures. The Earthquake Load Reduction Coefficient (R)
and the Overstrength Coefficient (D) to be used for the superstructure
and the relative storey drift limit are again different from the fixed-base
structures. For KK performance target, it is considered, with R=1.2,
D=1.2 and h =floor height, as the relative storey drift=0.005h , and for
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SH performance target, it is taken as R=1.5, D=1.5 and relative storey
drift=0.010h . R=1 is taken in the calculations for infrastructure.
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3. Since a very large part of the earthquake movement will occur in the
seismic isolation system, the level of ductility can be taken into limited
consideration in the designing of the infrastructure laying below the
isolation interface and the superstructure above it.
4. In a building with seismic isolators, these isolators providing the
connection of the superstructure to the infrastructure should be
designed in such a way as to have the highest possible security.
Therefore, the displacement calculation based on the design of
the isolators, the stability calculation of the isolator system and the
calculation of the loads affecting the insulators are performed at the
DD-1 Earthquake Ground Motion Level, where the recurrence period
is 2475 years, which is a very rare and the largest earthquake ground
motion considered. Moreover, taking into account the variations in
the properties of isolators that may occur due to factors such as aging
and environmental effects, loading speed and heating, variability in
production; the characteristic strength of rubber isolators (F ) and
Q
secondary (extra elastic) rigidity (k ), the lower limit values of the effective
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Year 2 / Issue 4 / July 2023 115