耐震、制振、そして免震
タイトルに挙げた代表的な地震対策手法について下記に参照したサイトの解説を一部引用し、これを英訳してみました。英訳に際してはDeepL（ニューラル機械翻訳）を使用しています。
A. 耐震構造 Earthquake resistant structure
A widely used structural system that withstands seismic energy with the strength and force resisting features of the main structure of the building, such as columns and beams.In a major earthquake, human lives may be saved, but damages to the building are likely to occur, making it more difficult to repair and to be used continuously.
① 耐震工法のメリット Advantages
This is currently the most commonly used method in Japan.
The least expensive of the three methods.
If built in accordance with the current building code, it is possible to build an earthquake-resistant home at no additional cost.
It can protect buildings from collapse in a severe earthquake.
Even in strong winds caused by a typhoon, you can hardly feel the shaking.
Basements, etc. can be installed.
② 耐震工法のデメリット Disadvantages
The shaking caused by earthquakes is very strong because the vibration is transmitted directly to the structure.The higher up the building, the more violently it shakes.
Damage to furniture and other items inside the building is iinevitable.
There is a risk of secondary damage from furniture overturning, etc.
Buildings are sturdy, but repeated shaking and multiple earthquakes can increase the likelihood of collapse.
After a major earthquake, maintenance costs are high.
B. 制振構造 Vibration control structure
Incorporating seismic damping materials that absorb seismic energy into the building struncture reduces vibration in the event of an earthquake. Since the main structural members such as columns and beams are not damaged, there is little damage to the building and the building can be used continuously.
① 制震工法のメリット Advantages
Almost always, it prevents the building from collapsing.
Less damage to the interior of the building than the earthquake resistant method.
Cheaper and shorter construction period than seismic isolation technique.
Resistant to repetitive shaking.
Resistant to the swaying forces of typhoons and strong winds
Almost no maintenance is required after an earthquake event.
② 制震工法のデメリット Disadvantages
The building itself is in contact with the ground, and this technique cannot be implemented if the ground is weak.
Although less restrictive than the seismic isolation method, it is not suitable for small sites due to the installation of seismic control devices.
For residential unit, It costs more than an earthquake-resistant method.
Damages to the interior of the building is less severe than in the earthquake resistant method, but it is more damaging than in the seismic isolation method, so it is advisable to use fittings/hardware to secure furniture.
Earthquakes are felt directly when you're inside a building.
C. 免震構造 Base-isolation structure, Seismic isolation structure
A seismic isolation device is installed between the foundation and the building structure to block the transmission of earthquake energy. . Even in the event of a major earthquake, there is little or no damage to the building and the furniture is less likely to fall over.
①免震工法のメリット Advantages
The building barely shakes during an earthquake event.
This is the best method for earthquake protection.
Damages to the interior of the building can be prevented.
Secondary damage from furniture falling over or other causes can be prevented.
② 免震工法のデメリット Disadvantages
During an earthquake event, the whole building will be moved by the seismic isolation system, so it is necessary to secure 1 meter and 50 cm of land space around an office building and a residential unit, respectively.
Cost is higher than the earthquake resistant and vibration control methods.
Regular maintenance is required.
The cost of replacing seismic isolation devices is also high.
May feel some shaking, albeit gradual.
Due to its short history, there are concerns about its technical and service life.
Only a limited number of contractors can perform the work.
Effective against earthquakes, but less effective against shaking caused by high winds and storms.
The installation of the seismic isolation system will raise the ground floor above the ground.
Basement can't be built because the seismic isolator is installed on the ground.
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