The devastation and tragic loss of life wreaked by the recent tornado in Oklahoma brings into focus engineering and construction measures which can be used to minimize the damage caused by such natural disasters.
A number of methods, ranging from the ingeniously simple to sophisticated, hi-tech measures, can be employed to dramatically raise the chances that structures situated near the maelstrom of a raging tornado emerge from its wrath intact.
While none of the houses in the direct path of the tornado in Oklahoma, which claimed at least 24 lives after tearing through a suburb of Oklahoma city, had much chance of being spared, other houses within the broader vicinity of the natural disaster could have reduced the damage they suffered significantly via the adoption of such measures.
According to Andrew Graettinger, a civil engineer from the University of Alabama, a trick as simple as using clips and straps to ensure that walls remain attached to rooves and structural foundations can spare as many as 85% of houses affected by a tornado under certain conditions.
The method has already become widespread along the Gulf Coast, which is frequently beset by hurricanes, and is extremely cheap, with the clips and straps required costing as little as USD$1 a piece.
“You need several hundred of them in the house, but it is not anything drastic. It is not a humongous expense, it is relatively inexpensive,” Graettinger said to NBC News.
Upmarket measures for tornado proofing new buildings and home are also available on the market, and primarily involve the use of the latest hi-tech materials to heighten resistance and durability.
Carbon fibre, which is more often associated in the popular imagination with forms of transportation such as boats and bicycles, can be used to build houses of heightened flexibility and toughness.
“Carbon fibre is incredibly strong and very flexible. The thinking behind carbon fibre architecture is that it can withstand earthquakes. It would be more flexible in the wind than regular structures,” says Bradley Quinn, an expert on advanced materials.
While straps and hi-tech materials may increase the likelihood that a house withstands the onslaught of a tornado, the most effective means of saving the lives of its occupants remains the construction of underground shelters or safe houses.
An EF-4 or EF-5 tornado, whose wind speeds are in excess of 200 kilometres per hour, are fierce enough to tear apart wood, or even level steel structures.
Unfortunately for Oklahoma, the soil of the state largely consists of clay, which increases the difficulty and expense of building subterranean storm cellars. Above ground safe rooms are an option, but these are also highly costly, coming in around several thousand dollars a piece.
The disaster in Oklahoma is set to expedite the construction of such measures despite their exorbitant cost, with the state and federal government providing financial incentives such as rebates to encourage home owners to build their own safe rooms.
By Marc Howe
Top Image: Rescue workers search for survivors among the wreckage. (Reuters: Gene Blevins)