Cyclone, as described by the meteorology is a large scale air mass that rotates around a strong centre of low atmospheric pressure. Well, so is typhoons and hurricanes. Cyclones, typhoons and hurricanes are the same phenomenon, but are known differently in different parts of the world. With Odisha in the wake of a massive cyclone Fani and the world in discussion of the recurring and ever strengthening cyclones observed around the world as a man made disaster in the era of ‘humans’, let’s talk on how to build to survive the cyclones and not just let our homes be another matchstick on fire.
Is it possible to build to survive the forces of nature
Unless its a nuclear bunker, regular homes do go depricit in times of worst case scenario. But we do can build to survive a large number of storms. In planning any construction be it residential, industrial, commercial or even a public sector undertaking like bridges, the very first scenario is a calculation of probabilities of the natural disasters that exists in particular to the region under consideration and to plan structures accordingly. In a country with a rising population, it is impossible to find a region that is invulnerable to all forces of nature. So the only means is to build Right and consciously.
Planning houses to withstand cyclones
Here are a few tips that has helped many structures to be still standing today.
The architecture/shape of the structure
The architecture/shape of the structure plays a crucial role in withstanding the cyclones, the dimensions are so preferred that the length of the structure to be no more than 3 times the width. The more square the structure the better it is in helping to withstand cyclones. Also another factor to consider is the strengthening the corners of the structure.
Interestingly a company Deltec Homes Inc.based in United States claims a 100% success in all their completed projects as they have been left with little to no permanent damages in the adverse conditions. They have a unique rounded design that have been able to distribute high pressure air evenly than to resist as it passes by the structure.
Roofing is one of the most vulnerable parts in cases of cyclones. The roof tiles and roofing sheets are prone to be blown off during the heavy storm. Once the structures roofs gets blown off, the structure is prone to failure as the high speed winds acts on the interior of the structure which can cause failure.
It is essential that all parts of the houses be soundly constructed as failure in any can cause further failure to the entire structure. Another precaution taken is the use of impact resistant glasses, for the window panes, which are not easily shattered by the flying debris.
Another essential detail in roofing is that it has been seen that the flat and gable roofing are prone to damages during tornadoes than hip roofs. It is seen as more pyramidal the roofing plan is, lesser the uplift of the forces from cyclone. Also it is recommended against the use of overhanging roofs in cyclone prone areas. Ensure that the roofings are properly fixed with the structure to prevent the chances of being ruptured or blown away in the havocs of disaster.
Ultra High Performance concrete
In ultra high performance concrete, a variant that is about 6 times stronger than regular concrete, can provide high structural integrity to the construct. UHPC and reinforcement steel can provide the necessary structural integrity to withstand the cyclones. The use of UHPC further extends to the fact that UHPC is almost non porous in nature, there by cutting chances of rusting of steel bars by providing a non porous insulation around the concrete. This can extend the longevity of the construct through providing protection against rusting of TMT bars.
RCC Structures for Tropics
RCC structures are more resistant to the forces of nature like cyclone when compared to masonry houses and timber timber houses that lack the necessary reinforcements and are much lighter and can be blown away by the heavy winds. For construction in tropicals like India, RCC structures are the most recommended where regions are prone to flooding, earthquakes and cyclones. Using grades like Fe 415 with the right proportion of strength and ductility do help in withstanding not just the shear wind pressures of cyclones, but also offers protection during earthquakes. This is a reason why grades like Fe 415 are preferred over higher grades which offers lesser ductility in construction.
RCC structure has the advantage over structures of timber where each section is vulnerable to the effects of the high speed wind. Special care must be ensured and usage of higher quality ties has helped buildings withstand cyclones. Another funny fact that was discovered in the wake of a hurricane that left a city strewn with debris was that the buildings and steel structures that survived while the others fell where of the same build except for the number of a few fasteners and screws on them. Go figure, a few screws left structures standing.
There are many more practices world wide, which are not much of importance in a tropical country like India, where houses of timbers are minimal. What is worth noting that in the havocs of disasters, even the well developed countries with building codes that were deemed as safe once, had them rethinking if the building really is as safe as they once thought. In a study after hurricane Micheal, on investigation of damages, the council finally did come to the conclusion that the well engineered construction do survive in the face of disaster and has called for even stricter building codes to prevent scenarios as in the past that had led to the loss of more than half the city’s structure.
Let’s break the silence and accept facts
Breaking a promise for a good cause is never a sin. So to air things out, the world is in discussion of the increasing man made ‘natural disasters’, a common scenario of time. So why are the fingers being pointed towards us for a phenomenon that has been present even before the birth of man as we know now. The reason rests with Global Warming, a fact that is an ever present discussion in today’s society as well as one of the very first phenomena in the text books for study, that are explained to kids. The fact that only about 0.8 C, has only been noted as the global rise in temperature in the last century, and that is including the highly prosperous yet polluting age of industrialisation, globalisation and the great wars. But how bad has the 0.8 C rise in temperature been is now available live to us. So, let’s pledge for a change.