Earthquake protective systems in civil engineering structures - Evolution and application

Earthquake protective systems offer an alternative technique to conventional seismic resistant design for improving the seismic performance of civil structures. These systems reduce the seismic forces by changing the stiffness and/or damping in the structures. Whereas conventional seismic design is needed for an additional strength and ductility to resist externally applied earthquake forces. The research and development works of such systems including passive, active and hybrid devices are ongoing intensively. The goals of this paper are to present a brief history of isolation techniques and to introduce these systems from passive devices to sophisticated ones and completely active systems. By focusing especially on the passive systems, development and progress involved in these systems are reviewed. A brief note is also made about applications and the conclusion of the recommended provisions from codes for new buildings and other structures is given.