CYCLONE RESISTANT BUILDINGS

CYCLONE RESISTANT BUILDINGS

A cyclone is a storm associated with high speed whistling and peaceful winds. It brings torrential down pours. A cyclone storm develops above tropical ocean and blows at speed as high as 200–240 km/hour. It is usually associated with lightning, thunder and continuous downpour of rain. Cyclones extend from a hundred and fifty km to 1200 km in lateral directions with forced wind gusts spiralling around a central minimal pressure area. The central spot of light winds and minimal pressure, known as the ‘eye’ of cyclone has a average diameter of 20 to 30 km.

This central eye is surrounded with a ring of very strong winds extending nearly 40 to 50 km over and above centre. This region is named ‘wall cloud’. In this spot strongest winds and torrential down pours occur. Beyond this region wind gusts spiralling extend outwards to big distances, which goes on reducing while using distance from the centre on the cyclone.

The following care must be taken in designing buildings in cyclone prone areas:
1. Foundations must be deeper
2. R. C. Chemical. framed structures are to end up being preferred over load bearing structures
3. Sloping roofs should end up being avoided.
4. Cantilever projections must be avoided.
5. Roof and parapet wall must be properly anchored to the columns and walls.
6. Height on the buildings should be restricted.
7. Suitable wind load should be considered in the building design.
8. Openings in the wall should be less. 9. Structure must not rest on loose soil.