In the last blog, we discussed a beach house that survived a category 4 hurricane. Like the Sand Palace, there are many buildings that have gone through a natural disaster and stood to tell the tale. One of the common types of disaster is an earthquake. There is been much research on understanding the earthquake and to build a structure capable of withstanding the effects of a deadly earthquake.
What are earthquakes?
Earthquakes are the shaking of the earth’s surface due to the sudden release of energy. An earthquake can be very weak that it is not even felt but there have been earthquakes that have crumbled an entire city. Earthquakes can also trigger other natural disasters like tsunami, landslide or volcanic activity.
What causes the building to become a pile of rubble?
The release of energy causes vibration of the earth’s surface. This result in a process called liquefaction of sand. The sand and water try to force its way to the surface from below the ground. This makes the soil loses its rigidity and making it into a form of fluid. So buildings on such soil collapse easily since its footing is lost.
Making the buildings earthquake-resistant:
It is not possible to make a building fully earthquake proof, but we could make buildings that can withstand earthquakes to a certain level. The main intention earthquake resistant building is to minimize the damage during a mild quake and prevent the collapsing during strong ones. This way the safety of the people and contents of the building is ensured.
How is it done?
There are few engineering techniques that are used to make earthquake resistant but the most popular of these techniques are Base Isolation method and Energy dissipation Device
Base Isolation Method:
The most popular form of earthquake resistant design, it is a collection of structural elements called isolators that are well placed to isolate the building from the shock waves. The isolators are placed above ground and under the building providing the safe isolation of the upper structure from the base. The LA City Hall, The Field Museum of Chicago and Utah State Capitol building all uses base isolators in their structure.
Energy dissipation device:
The main reason for collapsing of the building is due to excess energy release. So if it was possible to spread or dampen the effect of this energy on the building, we would salvage it from turning into a rubble. It is this same idea that is used by energy dissipation device or dampers. Dampers are also placed as structural elements like diagonal braces. The dampers absorb and store some of the energy that is passed throughout the building, thus damping the effects of the earthquake.
Like many other natural disasters, the earthquake can be quite deadly. It is not the earthquake that takes the life but the crumbling buildings. It is always best to prepare for the worst and build a home that protects the precious lives.