technical information

Seismic isolation building technology that flexibly absorbs the shaking of an earthquake and protects the lifeline of the building

Difference between seismic resistance and seismic isolation

There are two ways to protect buildings from earthquakes: "seismic resistance" and "seismic isolation."

Principle of seismic isolation and "4-second seismic isolation"

A seismic isolation structure is based on the idea of insulating a building from the ground by utilizing the properties of laminated rubber, which is stiff in the vertical direction and soft in the horizontal direction, and prevents the transmission of seismic energy to the building.
Although it is not possible to accurately predict what periodic components an earthquake has, if the primary natural period of the seismic isolation structure is set to 4 seconds or more, the response of the building will be almost constant regardless of the type of seismic wave. Response level is also reduced. In Table (1), we can see that the strength of the shaking is greatly suppressed after 4 seconds.
If this "4-second seismic isolation" is realized, it will be possible to maintain stability even in buildings built on soft ground.

"RSL seismic isolation system" that realizes seismic isolation for 4 seconds

The "RSL seismic isolation system" is often used in the construction of seismic isolated buildings.
The "RSL seismic isolation system" is a seismic isolation system that uses a combination of laminated natural rubber (Rubber), steel dampers (Steel), and lead dampers (Lead).

Role of each seismic isolation member

• ・Laminated rubber isolator: 4-second seismic isolation isolates ground shaking from the building.
• ・Lead damper: Absorbs vibrations of medium seismic intensity or less.
• ・Seismic isolation U-type damper/steel bar damper: Quickly converges the tremors of a large earthquake.

These synergistic effects make it possible to protect buildings and their interiors in complete safety even against the largest earthquakes.

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