Optimal design of base isolated active controlled MDOF structures

Active variable stiffness dampers used for base isolation of MDOF buildings reduce the response of the structure to unpredictable earthquakes and other horizontal loads. The system described in this paper has the advantage that the control forces in the devices can be changed in a wide range. The forces in the dampers are controllable and independent of interstory drifts and velocities. It is very convenient in cases where the value of the control forces, obtained according to the optimal solution, are less than those produced by other known devices such as friction pendulums. The efficiency of the proposed meted is demonstrated by means of a numerical example.