From Reuters Alertnet.org - NEWSDESK
By Anton Ferreira | 13 November 1998
Sandbags for Lunar and Martian Homebuilders?
HESPERIA, Calif., Nov 13 (Reuters) - Iranian architect Nader Khalili dreams of building homes on the planets, and he knows what materials he would use — sandbags and barbed wire.
He is already using them on Earth to build houses so stable they have won official approval from city building authorities on California's seismic fault line.
Khalili is the founder of the California Institute of Earth Art and Architecture (Cal-Earth) in Hesperia, 80 miles (120km) northeast of Los Angeles in the Mohave desert, where he and his colleagues are refining a technique he calls "superadobe."
"Superadobe has evolved over 23 years of looking for the simplest way to build, the simplest way needing the least time, the least money," Khalili told apprentice builders at a recent workshop at Cal-Earth.
Khalili, now in his 60s gave up a career as a skyscraper architect in the 1970s to pursue his quest to find a building method that would provide the world's poor with safe, comfortable, affordable housing.
STEP ONE - BAKE HOUSE TILL HARD
Touring his native Iran on a motorcycle, he experimented with a technique that turned traditional domed, vaulted adobe (mud brick) houses int rain-and earthquake-resisting ceramic structures by firing them for up to three days with giant kerosene burners.
The technique worked, but Khalili continued to look for a simpler way that would eliminate even the need to make mud bricks. He found it in "superadobe," created by filling sandbags with whatever earth is at hand at the building site and piling them up in rows to form walls.
Strands of barbed wire laid between rows of sandbags hold them together like Velcro. The roofs of Khalili's houses are self-supporting domes or vaults so no timber beams or trusses are needed, an important consideration in arid zones.
Khalili also advocates the use of domes or vaults as a way to reduce the destruction of forests in developed countries such as the United States where wood is often the main component in house-building.
"These techniques of building with domes and vaults have been developed over 4,000 years," he said. "The dome is the strongest structure - that's why they are used to contain nuclear power plants."
In 1984 Khalili made a presentation to the National Aeronautics and Space Administration (NASA) on how his methods could be used to build shelters on the Moon or Mars.
He said astro-builders could fill bags with the sand and grit of the lunar or Martian surface, reducing the need to transport construction materials from Earth at great cost. He also believes the sun's heat could be harnessed to make ceramic structures on the planets.
Human colonisation of distant worlds might be some time off, but Khalili passed a major hurdle in getting his ideas accepted on Earth in 1996 when Hesperia authorities endorsed superadobe as a safe residential building method.
SCEPTICS WIPE SMIRKS FROM THEIR FACES
"When he first proposed constructing buildings made of earth-filled sandbags stacked in domes, the building department was skeptical, to say the least," Hesperia city officials Tom Harp and John Regner said in Building Standards magazine.
"In fact, if we hadn't been trained to be courteous, we would have laughed out loud," they wrote in the magazine of the International Conference of Building Officials.
Hesperia authorities were converted to believers after they conducted earthquake tests on superadobe structures at the Cal-Earth site, they said. "The required test limits were greatly exceeded. Testing continued beyond agreed limits until the testing apparatus began to fail.
No deflection or failure was noted on any of the tested buildings."
Khalili compares his years of battling to get Hesperia to accept his methods with the strain of living through Iran's Islamic revolution.
"Our mission is to find the simplest way to build. It works, these things can be built. This is the way to go," he said. "The reason we are doing it here is because from the United States things go everywhere. Even though I developed this thing in Iran, they won't believe it until it comes from America."
Khalili said superadobe was also ideal for emergency housing for refugees from war or natural disasters. "You can just drop the empty bags and barbed wire from aircraft and send in an instructor to show people how to use them to build their own shelter."
© Reuters Limited 1998.
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