A new invention by a University of Melbourne PhD student will stop buildings from cracking due to shaking by earthquakes, impacts and blasts.
Dr John Stehle, now an engineer with Hyper Consulting, says he worked with colleagues at the University of Melbourne to design a super flexible system that can beat any level of earthquake shaking.
“Australian construction is not very good at resisting earthquake shaking,” he says. “You just have to remember the $1 billion of damage and 12 lives lost as a result of the 1989 Newcastle earthquake.”
Dr Stehle set out to see how a popular Australian building type, ‘The Band Beam Building’ would perform under earthquake conditions.
“Connections between columns and beams are critical for good building performance under loading events such as earthquakes. So we did some large scale tests in the lab on some critical building connections,” he says. “As we shook them slowly, we watched and recorded how they cracked and how strong and flexible they were.”
The resulting big cracks in the connections so concerned Dr Stehle that he then invented a new flexible building system that worked in resisting simulated earthquake shakes.
The system involves the use of plastic tubes wrapped around steel reinforcing bars near the joint region. This allows the bars to slip through the concrete under earthquake loading rather than gripping onto the concrete and tearing large cracks open. The formation of such large cracks is undesirable as it leads to a progressive “pancake” type of collapse.
There has been Australian and International interest in the system, including a number of practising engineers in California who are keen to implement the technology. However, further testing will probably be required. Dr Stehle aims to conduct further tests on full-scale buildings at large scale testing facilities in the U.S.
He is one of sixteen young scientists presenting their discoveries to the media, public and students for the first time, at Fresh Science.
“We’ve selected them from 105 national nominations, brought them to Melbourne, trained them and thrown them to the [media] lions,” said Niall Byrne, Chairman of Fresh Science. “It’s all about focussing public and media attention on Australian scientific achievement.”