A building constructed in such a manner that it has the ability to withstand hurricanes is known as hurricane-proof building. With the advent of advanced technology over the years, a variety of methods have been studied and tested, which can help a building survive strong winds and storm surges (flooding due to storms). There are a few things which are considered while designing such a building. They are - storm surge and wind loading considerations. Then, there are building components which need to be chosen correctly.
A storm surge mainly occurs in coastal areas. The waves generated due to strong winds are very powerful and can damage a building to a great extent. Hence, these beach-front buildings should be powerful enough to bear the waves of the ocean rising to 20 feet or more. If there is a chance that the waves can reach the building, it is ideal to elevate the building on wooden, steel or concrete pilings. The walls on the first floor are constructed using Sheetrock or drywall by default.
Sheetrock is a building material made of a layer of gypsum plaster pressed between two thick sheets of paper, and then kiln dried. As a result, these walls can completely deteriorate when wet or exposed to lateral forces, allowing high winds accompanied by water to pass through it. This situation, termed as gutting, is a frequent occurrence in areas that often receive storm surges. Constructing the walls on the first floor using sheetrock is not an ideal solution for such gutting. However, it can save the rest of the building from destruction.
Wind Loading Conditions
Wind loading conditions are associated with the construction of the roof of a building. Strong winds affecting the roof surface results in negative forces and creates a lifting force. There is a high possibility that a building can be destroyed in this way during a hurricane. This lifting of the roof or 'peeling' weakens the building substantially. To avoid this, the upper structure should be securely fixed through the walls to the foundation.
On the more conventional side of securing a roof, roof trusses (triangular brackets of brick or stone) are 'toenailed' into the top of the walls. Although these nails provide zero structural advantage, they are helpful in holding the trusses in place while the roof is being built. The rest is then left to the forces of gravity and friction to protect the roof. Nowadays, advanced technology methods have developed in such a way that the roof can be anchored to the walls. Trusses wrapped by metal straps nailed to the wall is another method for strengthening a roof.
Another makeshift arrangement would be using temporary straps of special low-elongation material. For example, a building made in 1994, may not have this facility. In that case, the building can now be temporarily strapped to the foundation. This will ensure the structural stability of the building. To make sure that it gets the best possible protection, hurricane harness strapping can be easily applied and later on removed. These methods are common for stable, stationary homes.
Earth Sheltering is another component in the construction of a building, strong enough to hold against hurricanes and tornadoes. Earth sheltering means using earth against building walls for external thermal mass. Earth sheltering reduces heat loss and helps maintain a steady indoor air temperature. That is precisely the reason why cellars and basements of buildings can be a safe refuge in case of a natural disaster.
Weak points like garages, doors, windows and other openings are easy targets for blowing debris and wind pressure. Once these give up, the whole building is at risk. Moreover, the roof may also be lifted off a building.
Here, hurricane shutters can prove effective.
- Door Specifications: Doors leading out of the house should open outward in hurricane-prone areas. In case of a hurricane, an inward opening door will be blown inside the house. Doors opening inward have potential to cause a major structural failure to the building.
- Windows: Usually in hurricane-prone areas, windows tested to withstand 150-mile per hour wind are installed. These windows should have glass with protective membranes and plastic panes. And these panes should be fixed more firmly than the normal window panes. In such areas, aluminum shutters can prevent a major damage.
The material which is most resistant to strong winds should be chosen amongst all the options available. Wood and concrete are the top choices during construction. However, wood has its disadvantages. It is vulnerable to dry rot and termite in warm, humid climates. Still, wood used effectively in construction of a building can help it withstand winds with high velocity.
Concrete can be used for the construction of a building to make it resistant to strong winds, pounding waves and in a few instances, flying debris. Reinforced concrete, a strong dense material which is used in home construction must ideally be reinforced with steel. This is also called 'rebar'. Rebar is liable to rust in humid conditions, but counter measures can be taken to nullify its corrosion due to moisture.
Hurricanes or any other natural disaster can prove to be extremely destructive, and can claim human lives as well. In spite of constructing protective buildings, there is bound to be some damage. The best thing to be done is to take all necessary precautions.