The conceptual design is to control the general direction in the process of designing seismic isolation structure.For a particular building

its structure can be seismic isolation or aseismic structure. The decision depend on a balance between seismic safety and investment. In general

a building with isolation structure is safer than that with aseismic structure. Isolation structure may be the only possible structure to meet high safety demand in the region with high basic seismic intensity. Isolation structure is also cheap in the region of seismic intensity above VII.The range of total stiffness of isolation layer is determined by isolative parametrs and admissible displacement of isolation layer. The isolative parameters include input earthquake acceleration and its basic frequency

admissible acceleration and damping of the structure. If the stiffness is larger than its upper limit

the acceleration of the structure will be too large. If the stiffness is lower than its lower limit

the displacement of the structure will be too large.The structure above the isolation layer should be with regular shape and arranged symmetrically to reduce eccentric seismic response. The structure also needs enough strength to keep safety of the building. The shear stress in isolated building should be above 70% of that in aseismic structure.