The north west, northern and north eastern coastlines of Australia are frequently battered by high winds and cyclones during the mid to late summer season.
In a high wind situation, the most vulnerable part of any structure to failure is the roof.
The following map of Australia clearly identifies these regions which have been classified by wind region. (For further information refer to AS1170.2 Part2 “Wind Actions”)
A major contributing factor to wind related disasters is the containment of flying debris. In a high wind situation, the most vulnerable part of any structure to failure is the roof. The cause of this is due to the suction forces created on the downwind side of the roof. The roof does not blow off, but is lifted by the suction forces.
These suction forces rise and fall as the wind gusts and then lulls, placing fatigue stresses on the roof connections.
If insufficient retention of the roof exists, fatigue failures occur and the roof will begin to separate and damage will then progress rapidly.
Once the roof has gone there is little chance the building will survive if the high winds prevail.
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