Base isolation is a one of the modern earthquake combating techniques in which the superstructure is decoupled from the foundation with the help of some isolation device. Base isolation reduces the demand on superstructure enabling use of lighter structural members. The magnitude of earthquake forces transferred to the superstructure can be affected by varying damping in bearings. An effort is made to study the effect of damping and end-conditions in bearings on the response of a base isolated four-storey RC frame to lateral forces. Damping in bearings is varied from 5% to 40% and response of...