Earthquake countermeasures


　Even though measures to people in the earthquake, seismic base isolation and vibration control, there are different things.
What buildings are being devised for what competitive earthquake.


Earthquake-resistant structure

The Earthquake has a different idea.
First "earthquake" is.
Seismic and is to prevent destruction of or damage to buildings caused by earthquakes.
Building Standard Law is to ensure that you have a minimum level of seismic capacity building of those things when designing buildings, and construction standards are set to allow.

The earthquake-resistant construction has two types of rigid structure and flexible structure.

Rigid structure.・・・Thick pillars, and firmly, so that competitive structure is taken to earthquake shaking. This structure, when the earthquake happened, the whole building shakes.
Is currently being used in the construction of low-rise buildings building shake during a short period mainly.
＜Strong point＞
・Finished as soon as the earthquake shaking fits.
＜Weak point＞
・Not suitable for high-rise architecture.

図1


Flexible structure・・・The slender pillars, according to the bow shakes like an earthquake. After the earthquake shakes for some time.
This structure is used when building a high-rise buildings sway in the main long-period.
＜Strong point＞
・Reduce the overall weight of buildings below a certain level by reducing the stiffness, it is possible to reduce the force of an earthquake.
・Rigid structure in high-rise buildings can be designed that can not be designed.
<Weak point＞
・Such as wind tends to sway.

図2



Seismically isolated structure

Then "seismic isolation" is.
Seismic isolation and is not subject to possible earthquake-induced forces (escape) it refers to.
Horizontally while supporting structure in the vertical direction of the isolator isolates the ground and building one with a flexible operating.
And absorbs the energy and vibration damper using.
The damper is lead damper, oil damper, wall or other types of vibration control.
＜Weak point＞
・Generally less stable than the buildings.
・The roll is to be effective, the pitch is often ineffective.
・Cost

Structural vibration control

And "Seismic Structure" is.
For preventing that the attenuation or amplification mechanism inside the building, refers to reducing the vibration of the building.
By reducing the shaking of the building, repeating earthquakes is useful because it reduces the damage of the structure.
For inexpensive and popular than seismic.