A series of shock waves at regular intervals shakes everything around us and all we are left with is debris and a cacophony of cries. Earthquake not only moves the land up and down but also side to side.
This side to side movement more than often takes down buildings and the lives residing in it. The need of the hour is to erect structures that are earthquake-resistant which will not only minimise the loss of lives but also prevent collapsing of buildings. While no structure can be entirely immune to these seismic activities but with technological implications we can surely prevent the damage to a great extent.
Objectives of building/reinforcing a structure that is earthquake-resistant
The primary objective will always be to save lives of hundreds and thousands of people that get affected by these natural calamities. Other than this, these technological implementations will also save us money put in making this infrastructure in the first place. Few prime objectives can be summed up as:
- Public safety. Saving as many lives and families as possible.
- Structure survivability. The life of a structure increases considerably.
- Lesser damages to structures. If a building has the strength to absorb the seismic waves, the chances of the structure staying unaffected are high.
How is a building made earthquake resistant?
Mostly buildings can carry their own weight as well as can take other floor and suspended loads, but are not necessarily resistant to side-to-side loads. The most dangerous structures are having unreinforced brick or concrete block. These kind of structures are made with bricks stacked on top of each other and held with mortar. The weight of the roof is carried straight down through the walls to the foundation. These buildings can crumble down like a stack of cards when hit by a lateral force.
To combat earthquake destruction, one way is to tie the foundations, floor, walls and roof into a rigid box that holds together when shaken by an earthquake.
Another technique applied as buildings get taller is called base isolation. Base isolation is a collection of structural elements that decouple the main structure from its foundations thus protecting a building.
A similar yet different engineering technique involves constructing buildings on a bed of ball bearings, springs or padded cylinders. These act as shock absorbers preventing the actual building from shaking or swaying side ways.
There are many more ways that have helped prevent infrastructural disasters to some extent and have paved the way for future developments – keeping the roof light (using lighter materials), building foundations excessively stiff and strong (like the El Castillo pyramid at Chichen Itza), using ‘tuned mass dampers’ (used in the Taipei World Financial Center), etc.
New technologies for a stronger infrastructural future
If we take into consideration the existing structures – seismic retrofitting is the answer for them. It involves modification of existing structures to make them more durable and resistant towards earthquakes and other natural hazards.
An innovative technology named as the rocking frames allows a building to be reoccupied quickly after an earthquake. This technique comprises of three main components, namely steel frames, steel cables and steel fuses.
There are many more innovations and experiments going on to ensure the safety of human life and also to save buildings all over the world from demolishing. With every technological advancement new milestones are yet to be reached in this field.
