December 2008

Specialist earth builder and guest researcher in the Faculty of Engineering and Information Technology, Peter Hickson, has combined one the world's most ancient building techniques, "cob" construction, with modern engineering methods to develop a model house as part of an effort to create low cost earthquake resistant housing for millions of people around the world.

On Wednesday 17 December at noon it was zero hour for the half-size model made of earth and bamboo when it was put to the test on the state-of-the-art UTS shake table, the only earthquake simulator of its kind in Australia. The four tests were based on the El Salvador 2001 earthquake which measured at 7.8 on the Richter scale. The first test was set at 100% intensity, the second at 125% intensity. The third and fourth tests represented the aftershocks that occur after the main earthquake hits and these were set at 100% intensity. Impressively, the model suffered minor cracks but remained standing.

Hickson has collaborated with Professor Bijan Samali, UTS senior lecturer and expert in Structural engineering and final-year engineering students Luke Punzet and Jean-Michel Albert-Thernet in building and testing the model. "If this were an actual building then it could have been safely reoccupied without any repair. It is an outstanding success because not collapsing and killing or injuring people is enough to claim success," said Professor Samali. Hickson has been given the go ahead to safely use his construction system anywhere seismic activity is common and a hazard to life.

"Cob is a building material made from subsoil, straw and water," Hickson said. "Clay is the binder, sand, silt and gravel the fillers and straw the reinforcing. Lumps of earth and straw mixture (cobs) are melded into a monolithic structure. It has been used worldwide for thousands of years and was a traditional building technique popular in England."

Hickson's house introduces many new technologies, but what makes his system unique structurally is the addition of internal bamboo reinforcing and the use of structural diaphragms.

"I believe well designed bamboo reinforced cob is the answer to sustainable housing for anyone living in areas where seismic activity poses a threat to safety. That's sustainable with all aspects of sustainability considered – spiritual/cultural, social/economic and ecological."

The model tested on 17 December was based on a prototype low-cost house Hickson has built in the Philippines. It was complete with windows, first floor, loft bedrooms and roof.

"Millions of people live in inadequate and temporary houses and many thousands of people, sometimes tens of thousands, die in the collapse of buildings during devastating earthquakes," he said. "These buildings are sometimes crudely built earth homes, but often are poorly constructed, using reinforced concrete, concrete hollow block or fired brick.

"Earth building material is abundant, widespread and freely available. Education, training or sharing knowledge is all that is required to make such homes safer if people are willing to adopt some simple changes to the way they build.

"Furthermore, by utilising local indigenous materials, vernacular styles and appropriate climate responsive designs, we will have also delivered the most sustainable solution for communities with limited resources."

Image: Top - Peter Hickson at work on test model; Bottom - The house upon which the model is based

For further information, contact:

Nancy Gewargis

Marketing Projects Manager

UTS:Engineering

02 9514 2637