Winds of 140mph can create 1,000lbs of force on an exterior door, according to the US’s Institute for Business and Home Safety. Those coming at 74mph, the lowest hurricane speed, can blow water 4in up a wall. In response to storms and other natural and man-made disasters, developers, architects, structural engineers and construction product companies have begun developing new technologies and methods to help buildings withstand the forces thrown at them.
The thousands of towers rising in Dubai, for example, must be prepared for high wind speeds. Those in San Francisco and parts of Japan need to be ready for dramatic seismic activity. Homes in south-east Asia must be able to face more tsunamis and those in the Caribbean and US Gulf Coast have to brace for hurricanes. Fires and, increasingly, bombs are also threats.
But that doesn’t mean a complete overhaul of the way buildings go up. “In general, changes in building technology to address disasters and attacks are less material-oriented and more refinements of modelling and re-evaluation of risk,” says Jonathan Ochshorn, a professor at Cornell University’s College of Architecture, Art and Planning.
Among the most important “refinements” are:
■More exhaustive computer models that test how buildings could deal with high wind or temperatures or ground shifts that echo earthquakes. Engineers use simulated “extreme events” to see how towers, such as Hong Kong’s International Finance Center, which opened in 2003, perform, says David Scott, a principal at design consultancy Arup. “That building was at level three or four” – meaning construction was partially completed – “but they did a complete re-evaluation of the design” after architects learned why and how the World Trade Center towers collapsed in 2001, he says. Proposed residential skyscrapers, from London’s Shard of Glass to Burj Dubai, expected to be the world’s tallest structure when finished, could get similar treatment.
■Wind tunnels that also allow designers to test how well a structure with dozens of storeys will bear high-force gales. Bill Baker, a structural engineer and partner at Skidmore, Owings and Merrill, the architects, says he redesigned the Burj Dubai after studying the original model’s performance in a wind tunnel. “We ultimately made the building much taller than we ever thought we could,” he says. The tests helped architects figure out how the structure’s design could “confuse the wind”, ensuring that higher floors would sway more slowly and less forcefully, thus diminishing the chances of residents getting motion sickness.
■Fake earthquakes tested on real houses. Through the NEESWood research project, engineers from universities around the US are building a wood-frame townhouse, detailed down to the stucco exterior, and subjecting it to shaking that mirrors the tremors felt in typical California earthquakes. Five stages of tests are just beginning and researchers expect to develop plans for helping owners of wooden houses prevent earthquake damage.
Product development is another important component of protecting property against disaster damage.
Two examples are:
■Fluid viscous dampers, sold by New York-based Taylor Devices since 1955 when builders of nuclear reactors used them to reduce dangerous vibrations from active pipes. The dampers, which are as small as 50cm by 10cm and absorb shocks from violent movements, are currently being tested in prefabricated walls in the NEESWood building. If they work, the walls may be available to consumers or contractors for about £500 each.
■Hurricane-resistant panels built of aluminium-based Reynobond and Kevlar, which were introduced to the market by architectural-products manufacturer Alcoa just this month. The panel system protects low-floor building façades from debris thrown around by hurricane winds up to 130mph. These “missiles” are considered the most damaging by-product of strong storms, breaking windows and damaging structural walls.
Clearly it takes a lot more than storm-proof shutters for a home to survive a unforeseeable disaster.
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