NONLINEAR CONTROL OF STRUCTURES IN EARTHQUAKES

The objectives of control of structures in earthquakes are to prevent injury to occupants and damage to contents and to protect the integrit y of the structure. Both objectives can be achieved through base isola tion and feedback control, whereby the structure is stabilized relativ e to the inertial space. Nonlinear on-off control with a dead zone in conjunction with direct feedback has the advantages of economy and sim plicity of implementation. Indeed, the actuators operate only when the velocity exceeds certain threshold values and only in response to sen sor signals at the same location. An example using two actuators, one on the base and the other at the top of the structure, shows very good performance of the control design.