Effects of local soil condition on base isolated building according to Turkish Earthquake Code

This study investigates the effect of local soil conditions on the use of seismic baseisolation for framed structures. The time interval of the 1999-Kocaeli Earthquake ismodified to obtain four different artificial earthquakes. The predominant periods ofthese artificial earthquakes coincide with the characteristic periods Tb of the local siteclasses defined in the Turkish Earthquake Code. Lead rubber bearings are selected asseismic isolators. Then, the fundamental periods of the structures are increasedgradually and each structure is analyzed with and without lead rubber bearings byusing time history analyses technique. The maximum accelerations, base shear forces,floor displacement values and relative drift ratios of each structure are compared witheach other under different soil conditions. It is concluded that the seismic base isolationtechnique is strongly affected by the predominant periods of the soil classes and also bythe height of the structure.