Imagine if we could build on fault lines with no fear of earthquakes causing mass destruction. New Australian research may have found the solution to safe living in seismic zones.
A small group of researchers at the University of Technology Sydney (UTS) have developed a simple yet revolutionary building system that could unlock large tracts of land in our towns and cities.
Associate Professor Behzad Fatahi and his team believe that the new technique, which inserts a sand cushion between a building and its concrete piles, will allow high-rise towers, bridges and other infrastructure to be built on active fault lines.
“This is a world first,” he says.
Professor Fatahi, a geotechnical and railway engineer, says fault lines, caused by seismic activity, stretch along the east coast from Brisbane to Melbourne and across the continent to Adelaide and Western Australia.
“We have this fault line map of Australia and construction goes on around those lines,” he says. “This new construction technique opens a new door so that we can build upon those fault lines – particularly on the east coast where we have a shortage of commercial land available.”
Current design codes in Australia do not allow building construction in the vicinity of fault lines, and usually impose a setback zone from the fault trace to avoid ruptures across structures.
Using an advanced 3D computer model, the UTS research team has shown that a bed of sand between the base of a building and its concrete piles would help absorb the impact of any fault rupture, reducing excessive building tilting and foundation failure.
“We stop the movement at the foundation level so whatever is above the ground – at any time of construction – would be protected,” he says.
<>An outline of how the technique works (source).
High-rise buildings are at particular risk when the fault occurs in the middle of the foundation; a moving tectonic plate coming into contact with a static tectonic plate causes significant structural distress, leading to potential tilting of the building, foundation failure and even buildings shearing in half.
According to Professor Fatahi, the new building technique could be used on any type of high-rise structure, but is equally applicable to transport infrastructure such as road and railway bridges.
“Exactly the same technique applies to bridge construction because a bridge pier looks like a concrete building and under that you have a foundation,” he says. “So this new building technique has a huge potential benefit.”
While the UTS team has yet to test the construction technique in a scale model, the new system has several advantages – such as its low cost, adaptability and simplicity.
Professor Fatahi says costs are kept down by using compacted material found on site and there are other savings in using shorter concrete piles. “This solution is so simple, it’s hard to believe. And it’s very cheap,” he says.
Subject to regulatory approval (and industry acceptance), the UTS team is hopeful that its new sand-based foundation system could be introduced to Australian building sites within the next five to 10 years, but the technique could also be of great interest to earthquake-prone countries around the world.
“I’m hoping that some of our neighbours, like Indonesia and New Zealand, could be using this technique even earlier because they have a pressing need for help,” says Professor Fatahi.