The document discusses different types of seismic isolation systems used to protect buildings from earthquakes. It describes active control systems that use computer systems and actuators to control structural response during seismic events. Passive control systems are also outlined, including irreversible displacement systems that use sliding components and plastic systems that absorb energy through lead dampers. Finally, common bearing systems for seismic isolation like rubber and lead-laminated bearings and sliding bearings are explained.

1. Seismic Isolation System

2. The Principle Of Seismic Isolation
• All the operations that are developed in order to protect the buildings
against the earthquakes, thus providing the security and comfort
conditions under service loads and that include placing certain kind of
additional elements in the building are named seismic isolation in
general.

3. Classification Of Seismic Isolation System
• Active Control Systems
• Passive Control Systems

4. Active Control Systems
• Active Mass Damper
• Active Variable Stiffness
• Active Passive Composite Tuned Mass Damper

5. Active Mass Damper
• In this system, by forming actuator control force, the acceleration,
displacement and velocity of the structure affected by lateral forces
are controlled by computer systems.

8. Active Variable Stiffness
• In this system, there is no need for forming of actuator control force.
However, elimination the resonance that results from coinciding of
fundamental period of the system and ground motion period
depends on choosing the appropriate rigidity for the system and
making the corresponding design. They are developed for utilization
in case of strong ground motion.

10. Active Passive Composite Tuned Mass
Damper
• The hybrid structural control systems, which were developed in the
recent years, are based on joint utilization of both active and passive
systems.

13. Passive Control Systems
• Irreversible displacement systems
• Plastic systems

14. Irreversible Displacement Systems
• Irreversible displacement systems consist of balls or rolls. By the
means of these rolls, the structure can move horizontally during an
earthquake.
• In these systems, the amount of dissipated energy is given by
multiplication of the friction force and displacement.
• Sliding systems are frequently used in applications due to the ease in
construction and economic cost.
• They consist of sufficient number of rolls that are placed
perpendicular to each other or spherical steel balls between the steel
plates.

16. Plastic Systems
• This system is developed, by benefiting from the plasticity of lead,
that provides ideal energy absorption for seismic isolation and other
vibrations.
• In these systems, usually there is a cylinder that contains lead and a
piston that moves with difficulty inside that cylinder. The lead in the
cylinder limits the motion of the piston, so that absorption of the
energy is achieved.
• Lead extrusion dampers are generally used for controlling the major
displacements.

18. Rubber Bearing Systems
• Rubber Laminated Isolators
• Lead Laminated Rubber Bearing Systems

19. Rubber Laminated Isolators
• The rubber laminated isolators are formed through vulcanization of
thin steel plates to rubber plates.

21. Lead Laminated Rubber Bearing Systems
• Lead Laminated Rubber Bearing systems are constituted by
steel/rubber laminated layers with a lead nucleus embedded in the
middle, and they are highly developed seismic isolators

24. Sliding Bearing System
• A sliding system is considered and easier strategy to approach and
also the easiest method that have been developed.
• The basic concept of a sliding system is to reduce floor accelerations
at the expense of shear displacements between the foundation and
upper structure.