BUILDING STANDARDS
Sydney Morning Herald
Monday March 28, 2011
There are not many buildings that could withstand the force of a tsunami like the one that hit Japan this month or Indonesia in 2004. However, construction standards and requirements in many countries have helped reduce the death toll from natural disasters such as earthquakes and cyclones.Engineers have developed techniques for reducing the impact of earthquakes on buildings and other structures. "Damping" devices, which act like car shock absorbers, can be installed to absorb the kinetic energy of the earthquake and turn it into heat energy.In large earthquakes, buildings deform the materials from which they are constructed bend and twist. However, buildings constructed with ductile materials (such as steel and reinforced concrete) are more likely to survive an earthquake with less damage.Bracing the frames of buildings also helps to counteract the lateral forces imposed by seismic waves. Tall buildings in quake-prone regions are usually wide at the base and have most of their weight in the lower floors.In Australia, a number of building codes have been put in place following natural disasters such as cyclone Tracy in 1974 and, more recently, the 2009 Victorian bushfires.Cyclone building codes set out how roofs should be attached to walls and how walls should be attached to foundations to withstand winds of up to 280km/h.For residences built in bushfire-prone regions, a new Australian Building Standard has been released. In the most extreme fire-risk areas, houses must now be built on a concrete slab and external walls must be constructed of non-combustible materials such as brick veneer or concrete. The roof, verandah or deck, walls and roof joints must be sealed to guard against embers; door frames have to be constructed from fire-resistant timber and shutters from aluminium or other non-combustible materials.
© 2011 Sydney Morning Herald
