A Comparative Study on Seismic Isolation Applications in Turkey

Design of seismically isolated hospital structures have become popular in Turkey within last five years especially after Ministry of Health’s policy change. The new hospital complexes of about twenty campuses has been either under design or scheduled for planning for the next five years. The Ministry strictly requires use of seismic isolation systems for high risk seismic regions not only to mitigate the adverse effect of earthquakes on structures but also to keep operating expensive medical devices just immediately after the earthquake. Since the technology has been very new to Turkish market, a flux of manufacturers promoting different products were inevitable that have created some richness of education that also sometimes ended up in confusions. Therefore, the selection of seismic isolation systems for different geometries of structures over different soil conditions have become a hurdle for the engineers who has started learning this new technology. In this study, seismic isolation systems used at some of the hospital designs have been compared in terms of types, sizes, mechanical properties, expected performances. The case study includes five hospitals in which two of the complexes have almost been completed and three of them are still under construction. In many cases, friction pendulum based systems and lead rubber bearings have been selected based on the detailed analytical studies. It shall also be noted that two of the hospitals are very close to an active fault that required a comprehensive study of near fault effects in seismic hazard computations.