It’s not often that Australia and earthquakes are synonymous but there has been at least one major earthquake in every decade over the last century, making seismic engineering a valid area of interest in this country.
While the Newcastle earthquake of 1989 would perhaps be the most notable in people’s minds, the biggest quake in Australia actually occurred the year before, in Tennant Creek in the Northern Territory, at a magnitude of 6.6.
Engineering researchers at the University of British Columbia (UBC) in Canada have developed a new seismic-resistant, fibre-reinforced concrete which can be retrofitted to existing buildings to reinforce them against seismic activity.
The material, engineered at the molecular level to be strong, malleable and ductile, is capable of “dramatically enhancing the earthquake resistance” of a seismically vulnerable structure. Known as Eco-friendly Ductile Cementitious Composite (EDCC), it is applied as a thin coating on surfaces and has been successfully tested to magnitude 9.1.
“We sprayed a number of walls with a 10 mm-thick layer of EDCC, which is sufficient to reinforce most interior walls against seismic shocks,” Salman Soleimani-Dashtaki said, a PhD candidate in the Department of Civil Engineering at UBC.
“Then we subjected them to Tohoku-level [Japan] quakes and other types and intensities of earthquakes - and we couldn’t break them.”
EDCC combines cement with polymer-based fibres, fly ash and other industrial additives, making it highly sustainable, according to UBC Civil Engineering Professor Nemkumar (Nemy) Banthia.
“By replacing nearly 70% of cement with fly ash, an industrial by-product, we can reduce the amount of cement used,” Professor Banthia said.
“This is quite an urgent requirement as one tonne of cement production releases almost a tonne of carbon dioxide into the atmosphere, and the cement industry produces close to 7% of global greenhouse gas emissions.”
The first project EDCC will be applied to is a primary school in Vancouver over the coming months and it will also be made available to retrofit a school in Uttarakhand, a highly seismic area in northern India.
The UBC researchers believe EDCC also has other uses: pipelines, pavements, off-shore platforms, blast-resistant structures, and industrial floors.
Image: EDCC testing with Prof. Nemy Banthia (left). Videos can be viewed on YouTube and Dropbox as well as more images. Source: UBC