This paper focuses on the investigation of a hybrid seismic isolation system with passive variable friction dampers for protection of structures against near fault earthquakes．The seism ic isolation can be implemented by replacing the conventional columns fixed to the foundations by seismic jsolating ones．These columns allow horizonta1 displacement betw een the superstructure and the foundations and decouple the building from the damaging earthquake motion As a result．
the forces in the structura1 elem ents decrease and damage that may be caused to the building by the earthquake significantly decreases．However,this positive effect is achieved on account of displacements occurring in the isolating columns．These displacements become very 1arge when the structure is subjected to fl strong earthquake．hi this case．impact may OCCUI。
between the parts ofthe isolating column yielding their dam age or collapse．In order to 1imit the displacements in the isolating columns，it is proposed to add variable friction dampers．A method for selecting the dampers’properties is proposed．It is carried out using an artificia1 ground motion record and optima1 active control algorithm．Numerical simulation of a seven— story structure shows that the proposed method allows emcient reduction in structural response and Iimits the displacements at the seismic isolating columns.....
