Designing earthquake-resistant buildings
As many as 100,000 earthquakes of + 3 magnitude hit the earth every year. According to estimates, some 15 million people have died with losses approximating hundreds of billions of dollars in recorded history.
Earthquakes are impossible to predict and safety precautions must be taken to make buildings safer. If Chandra’s work pays off it could make future earthquakes far less costly both in the number of lives lost and the financial impact.
Chandra's doctoral programme is titled Seismic Analysis of Shape Memory Alloy Based Dampers, which in layman's lingo means he is working on cutting edge technology aimed at making buildings more earthquake resistant, potentially making seismic events much less devastating in future.
He is working with Nitinol, an alloy of nickel and titanium which has “many unusual properties including shape memory, which means it can be deformed but then go back to its original shape.”
Nitinol belongs to a family of smart materials called Shape Memory Alloys (SMA). The unique properties of these materials significantly help reduce the damage associated with severe earthquakes, such as the one that struck Christchurch, recently. The reason for this is that earthquake engineers actually design buildings to be damaged during very large earthquakes!
There is a method to the madness because as the building becomes damaged it absorbs the earthquake’s energy. As long as the building does not collapse, crushing its occupants, then the building has done its job. There is a downside though and that is the enormous repair bill.
Chandra says he is, “Looking at the possibility of using the alloy to make energy absorbing dampers which will absorb energy with little or no damage to the building and therefore help to reduce the repair bill after a very severe earthquake, as well as by reducing casualties.”
Chandra says, “This material could provide an excellent way to make the dampers on buildings work a lot better. You need a material that can eat away the earthquake’s energy and not let it affect the stability of the building. We are aiming to create buildings that will not only survive the biggest magnitude 9 earthquakes, such as in Japan earlier this year, but do so with only minor damage.”
“Many of the buildings in Christchurch were still standing after the quake but were unsafe to use again, so will have to be knocked down, or require major repair, vastly increasing the cost. We are aiming to avoid that with this technology. This could potentially save lives and money. It is an expensive material, but in terms of the benefits it can bring it is very cost effective.”
The system works with a series of dampers at the bottom of buildings which absorb and dissipate the energy of the shaking earth and stop it pulling the building apart. Chandra’s PhD supervisor Dr Sean Wilkinson, a Senior Lecturer in Civil Engineering and Geosciences at Newcastle University says, “The work that Chandra is doing is at the cutting edge of earthquake proofing technology.
The work is still at an early stage and is being fully tested in our labs, but we are confident there is something here which could make a big difference to the safety of cities in earthquake zones. Chandra’s research can be applied to local construction here and shared internationally.”