الفهرس 
1. CHAPTER (1): INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Over years, considerable attention has been paid to seismic behaviour of structures with vibration control systems. Passive, active, semi-active and hybrid control systems have been used in buildings that might be subjected to high seismic activity. Among those devices, Base Isolation (BI) is a passive vibration control system that partially absorbs input seismic energy before it is transmitted to the superstructure. Passive vibration control system is considered the simplest one in implantation on buildings among vibration control systems. However, the passive control system sometimes may be considered unsuitable in implantation in buildings because it leads to constant behavior irrespective of the changing nature of coming seismic waves. This behavior may be considered the main shortcoming in the use of passive control. Seismic behaviour of structures is influenced by many factors. Among these factors, ground motion characteristics and structural irregularity have dominant effects on the seismic performance. In addition, vertical irregularity of R.C. building may pose high challenge on its behaviour and may increase its seismic vulnerability. In present research, four models will be investigated; these models represent regular and vertical irregular R.C buildings with fixed base or base isolation devices. Time history analyses are performed for regular and vertical irregular buildings under the effects of seven different earthquake records. A comparative study is made among periods, base shears, interstorey drifts and displacements of the different models. The study shows that using of base isolation would lead to increase the period of investigated models. Moreover, it would lead to reduce base shear and interstory drift. On the other hand, using base isolation increases the lateral displacement at the lowest floor (floor above the location of BI device), while it is decreased drastically as moving to the top floors. As a result, base isolation may be considered as effective seismic response control device for vertical irregular buildings as well as regular buildings.