Earthquake-proof buildings

More than a thousand deaths could be prevented every year if buildings were made to withstand earthquakes. But so far few developing countries have had access to the often expensive and complicated technology needed to make buildings earthquake-proof.

Now a team at the University of Sheffield in the UK has applied a new technique in tests where a full-size concrete building was subjected to similar forces as those seen in the devastating 2010 Haiti earthquake - without it collapsing.

Strapping metal belts tightly around a building's concrete columns kept the material from cracking and collapsing under strain during the tests.

"The strapping works very much like a weightlifter's belt, by keeping everything tightly compressed to reduce tension on the concrete columns of the structure," says Professor Kypros Pilakoutas, who has been heading the research team in Sheffield.

"The column is constantly confined under lateral pressure, so when there is seismic loading the concrete is not going to open up and crack and fail," Professor Pilakoutas says.

The tests, published in the Journal of Earthquake Engineering, involved putting a concrete structure through a simulated earthquake on a specially constructed seismic table, which shakes back and forth like the ground during a quake. When reinforced with the metal belts, the concrete would still sway back and forth, but never collapse.

"Our method not only makes the building stable again very quickly, but it increases the building's ability to deform without breaking, making it more able to withstand further earthquake movement," he says.

Making damaged or partially collapsed homes safe in the event of aftershocks would allow people to move back in much quicker. That would take away many of the risks to health associated with displaced populations.

Only two people would be needed to secure a simple dwelling in a matter of hours, and the Sheffield researchers estimate the cost per house to be around 250 euros ($343).

Developing world problem

The latest major earthquake hit the Philippine island province of Bohol in October 2013. More than 200 people died, and about 900 were injured.

"The most common cause is simply buildings falling on them," says Christine Cassar. Cassar travelled to Bohol as a rescue volunteer on behalf of Disaster Aid UK, a Rotary International-linked aid and rescue organization.

Cassar says she welcomes solutions such as the one developed by the University of Sheffield to make houses safe in earthquake areas.

"It's absolutely vital, that's the only way you can safeguard people's lives," says Cassar. "One of the challenges we had was getting aid to the communities that were badly hit, because all the bridges had been destroyed. So if these techniques could be used to reinforce bridges, then that would mean more aid could get through faster - you are literally talking about saving people's lives."

Earthquake-prone regions in the developed world, such as Tokyo and California, have invested heavily in protecting new and old buildings from seismic activity.

By contrast, developing countries often fail to prepare for earthquakes mainly for two reasons: a lack of money and a tendency to forget too soon.

"We still see some damaged buildings in Mexico City. But people just forget how fragile these buildings are," says Reyes Garcia, a Mexican PhD student working alongside Professor Pilakoutas at the University of Sheffield. Mexico City was hit by a magnitude 8.1 earthquake in 1985. The quake killed more than ten thousand people.

"We're not conscious that we are basically in seismic zones, that we are going to have an earthquake and that's going to definitely going to happen at some point in our lives," says Garcia.

Student ambassadors

Professor Kypros Pilakoutas now hopes knowledge of how to implement the metal belt technology can be spread to developing countries which experience high seismic activity.

Some of his own students might be the best ambassadors for the solution.

"We're always a very international team here in our group. Three or four of these PhD students had to go back home during their studies because there was an earthquake in their home countries," says Professor Pilakoutas.

"In two cases their homes were damaged. So these people will go back and they'll train the local engineers and people in these technologies."