The design of structures with seismic isolation is based on the principle of separating the superstructure (components of the building located above the insulation interface) of the movements of the substructure ground, through horizontally flexible elements, generally located between the structure and its foundation or at underground sky level (substructure). However, there are cases where insulators have been placed on the upper floors.
 
The incorporation of seismic insulators allows reducing the rigidity of the structural system, making the vibration period of the isolated structure approximately three times the period of the structure without the insulation system.

 

Seismic isolation is used for the protection of various types of structures, both new and pre-existing structures that require reinforcement or rehabilitation. Unlike conventional structural reinforcement techniques, seismic isolation seeks to reduce efforts at levels that can be resisted by the existing structure. Because of this, the basic seismic isolation is especially useful for the protection and reinforcement of historical and patrimonial buildings.
 
​For houses, the system is similar to that of a building. In this case, isolated lugs are used as the foundation in which a seismic insulator is placed and on this, the floor girders or links together with the slab of the floor on which were displaced the levels of the house.

​

This system can be used both in new constructions and in constructions that are already in use, but the best thing is to introduce these safety devices during the construction to avoid the costs of structure intervention.
 
​Costs of this system are around 3% to 8%of the total cost of the work. But it's much safer and cheaper than not having it because it prevents the collapse of the structure by resonance.