Investigation of seismic isolated structures with additional energy dissipation devices at isolation level

In this thesis study, the changes in the behavior of buildings designed with seismic isolation by adding additional energy dissipation devices used in the seismic isolation floor to the system were examined. Eleven ground motions were selected for each structure and nonlinear analyzes were performed in the two-dimensional time domain; vertical components of ground motions did not included. The main motivation for using additional dampers is to reduce the displacement demands of the isolators and observe the changes in the superstructure. It was aimed to control the isolator demands at different points and to ensure similar demands as much as possible, and the hysteretic behavior of the isolators was shown. In the superstructure, comparisons were made considering story accelerations, interstorey drifts and total shear force. The number of dampers was increased according to the center of mass and center of rigidity of the structure, and each analysis result was compared with the initial state of the structure. According to the results obtained, adding additional dampers in certain quantities and at appropriate positions based on centers of the structure to the isolators structure did not negatively affect the superstructure behavior. Interstorey drifts and story accelerations were kept within certain limits, and the total shear force remained at reasonable levels. Isolator displacement demands for structures subject to torsional behavior due to the center of rigidity and center of mass not overlapping are brought closer together and a more uniform behavior was achieved.