While there are many ways of constructing new buildings to make them earthquake-resistant, what can be done to strengthen buildings that are already standing? A new type of concrete could be the answer.
Developed at Canada's University of British Columbia (UBC), the concrete is sprayed onto existing walls and reportedly allows them to withstand tremours that would otherwise reduce them to rubble.
Known as Eco-friendly Ductile Cementitious Composite (EDCC), the concrete contains polymer-based fibres. These give it a strong yet malleable quality, not unlike steel, which tends to flex under pressure instead of crumbling like traditional concrete.
In addition to this, almost 70 percent of the cement in the material is replaced with an industrial by-product: Fly Ash. This is what makes it eco-friendly, as cement production produces almost seven percent of global greenhouse gas emissions.
In lab tests, a 10 mm-thick layer of EDCC was applied to walls made of traditional concrete blocks, which were then subjected to simulated tremours of a 9.0-9.1 magnitude – the same as the earthquake that struck Tohoku, Japan in 2011. The walls held up while their uncoated counterparts collapsed.
“It can take shaking of about 200 percent level of the actual intensity of the 2011 Tohoku earthquake which was a 9.1 magnitude event,” PhD candidate Salman Soleimani-Dashtaki said.
Plans now call for the first real-life application of the technology to occur within the next couple of months, as EDCC is applied to the walls of Vancouver's Dr Annie B Jamieson Elementary School. The UBC-hosted Canada-India Research Centre of Excellence is also making the material available for the seismic retrofitting of a school in northern India.