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Tornadoes A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, alth ...
,
cyclones In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an an ...
, and other storms with strong winds damage or destroy many buildings. However, with proper design and construction, the damage to buildings by these forces can be greatly reduced. A variety of methods can help a building survive strong winds and
storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...
.


Storm surge considerations

Waves along coastal areas can destroy many buildings. Buildings should preferably be built on high ground to avoid waves. If waves can reach the building site, the building should be elevated on steel, concrete, or wooden pilings or anchored to solid rock.


Wind loading considerations


The foundation

Wind on the roof surfaces can cause negative pressures that create a lifting force sufficient to lift the roof off the building. Once this occurs, the building is weakened considerably, and the rest will likely fail as well. To minimize this vulnerability, the upper structure ought to be anchored through the walls to the foundation. Several methods can be used to anchor the roof. Typically, roof trusses are "toenailed" into the top of the walls, which provide insufficient force to resist high winds. Hurricane ties nail into the wall and wrap over the trusses to provide higher force resistance.


Mobile home tie down to the foundation

Interlocking metal pan roof systems installed on mobile homes can fail under the pressure differential (lift) created by the high-velocity winds passing over the surface plane of the roof. This is compounded by the wind entering the building allowing the building interior to pressurize, lifting the underside of the roof panels, resulting in the destruction of the building. One example of pan roof systems can be found in this document fro
Structall Building Systems
. To mitigate this pressure differential, pre-installed aluminum tabular channels can be permanently fastened perpendicularly across the top of the interlocking ribs of the metal roof system without disturbing the flow of rainwater at the eaves mid-span and ridge locations of the building.


Earth-sheltering

Earth-sheltered construction is generally more resistant to strong winds and tornadoes than standard construction. Cellars and other earth-sheltered components of other buildings can provide safe refuge during tornadoes.


Dome homes

The physical geometry of a building affects its aerodynamic properties and how well it can withstand a storm. Geodesic dome roofs or buildings have low drag coefficients and can withstand higher wind forces than a square building of the same area. Even stronger buildings result from monolithic dome construction.


Log house

A Category 5 hurricane-proof
log house A log house, or log building, is a structure built with horizontal logs interlocked at the corners by notching. Logs may be round, squared or hewn to other shapes, either handcrafted or milled. The term " log cabin" generally refers to a sm ...
is resistant to winds up to . Wall logs in such construction must be made of
glued laminated timber Glued laminated timber, commonly referred to as glulam, is a type of structural engineered wood product constituted by layers of dimensional lumber bonded together with durable, moisture-resistant structural adhesives so that all of the grain r ...
and all other components of the house, including hurricane straps, must be hurricane-resistant.


Round house

A round, or multiple-sided home, is more resistant to hurricane strength winds. The round design allows the wind to blow around the home, reducing the build-up of pressure on one side. Additionally, with the roof and floors built using a radial truss array, that allows any potential energy from sustained winds to disperse across the entire structure instead of building up in one area.


Building components

Building openings such as garage doors and windows are often weak points susceptible to failure by wind pressure and blowing debris. Once failure occurs, wind pressure builds up inside the building resulting in the roof lifting off the building.
Hurricane shutters Hurricane coverings, commonly known as shutters, are used in hurricane mitigation to protect houses and other structures from damage caused by storms. Hurricane shutters are used to prevent windows from being broken by flying objects during a sto ...
can provide protection. Doors can be blown into the house by wind, causing potential
structural failure Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking and includes the study of past structural failures in order t ...
(see http://www.floridadisaster.org/hrg/content/openings/openings_index.asp#Hinged_Exterior_Doors). Windows can be constructed with plastic panes, shatterproof glass, or glass with protective membranes. The panes are often more firmly attached than normal window panes, including using screws or bolts through the edges of larger panes. Concrete anchor screws are used to secure windows to the concrete structure surrounding them. Wood has a relatively high degree of flexibility, which can be beneficial under certain building stresses.
Reinforced concrete Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low ultimate tensile strength, tensile strength and ductility are compensated for by the inclusion ...
is a strong, dense material that can withstand the destructive power of very high winds and high-speed debris if used in a building that is designed properly.


Regulation

After
Hurricane Andrew Hurricane Andrew was a very powerful and destructive Category 5 Atlantic hurricane that struck the Bahamas, Florida, and Louisiana in August 1992. It is the most destructive hurricane to ever hit Florida in terms of structures damaged o ...
in 1992 caused $16 billion in insured damage, the state of
Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...
established new building standards and enforcement. The state increased performance criteria for wind-load provisions and adopted new wind provisions from the
American Society of Civil Engineers American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...
. One important addition to the new code was the requirement of missile-impact resisting glass, which can withstand high-velocity impact from wind-borne debris during a hurricane. Many houses built in South Florida since Hurricane Andrew are cinder block masonry construction reinforced with concrete pillars, hurricane-strapped roof trusses, and codes requirements for
adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...
s and types of roofing. Florida also designated high velocity hurricane zones (i.e. High Velocity Hurricane Zone) with special requirements defined for
Miami-Dade Miami-Dade County is a county located in the southeastern part of the U.S. state of Florida. The county had a population of 2,701,767 as of the 2020 census, making it the most populous county in Florida and the seventh-most populous county in ...
and Broward Counties. Hong Kong requires many structures to withstand winds from typhoons.


Examples of cyclonic construction methods

Residential construction in Darwin Northern
Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
Image:Start-bars.jpg, Starter bars cast into concrete slab for blockwork wall reinforcing, Image:Raft-slab.gif, Detail of reinforcing steel at edge of concrete raft slab Image:HD-bolts.jpg, 16mm Cast in hold down bolts. 150 to 300 long cast into blockwork bond beams Image:Hold-down-truss-connection.JPG, HD bolt to truss connection. also seen, metal roof batten fixing, speedbrace end fixing. Image:Connect-straps.jpg, Typical roof member connector straps. Image:Shearwalls.jpg, Internal mig welded shearwalls Image:Shearwall-slab.jpg, Shearwall to slab connection, M12 chemsets through 6 plate washers, typ. at ends and 900ctrs. Image:Blockwork-fence.gif, Sketch of 200 series reinforced blockwork fence wall. Terrain category 3 (close to sea front) Image:In-ground-foundation.gif, Sketch of typical foundation layout for sloping ground.


See also

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Autonomous building An autonomous building is a building designed to be operated independently from infrastructural support services such as the electric power grid, gas grid, municipal water systems, sewage treatment systems, storm drains, communication services, ...
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Building A building, or edifice, is an enclosed structure with a roof and walls standing more or less permanently in one place, such as a house or factory (although there's also portable buildings). Buildings come in a variety of sizes, shapes, and func ...
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Natural building A natural building involves a range of building systems and materials that place major emphasis on sustainability. Ways of achieving sustainability through natural building focus on durability and the use of minimally processed, plentiful or renew ...
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Bubble Houses (Hobe Sound, Florida) The Bubble Houses are two historic bubble or airform houses located next to each other at 9086 and 9096 Southeast Venus Street in the Zeus Park neighborhood of Hobe Sound, Martin County, Florida. History Completed in 1954 by Airform, the Bubb ...
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Dymaxion house The Dymaxion House was developed by inventor and architect Buckminster Fuller to address several perceived shortcomings with existing homebuilding techniques. Fuller designed several versions of the house at different times — all of them ...
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Hurricane preparedness Cyclone mitigation encompasses the actions and planning taken before a tropical cyclone strikes to mitigate damage and injury from the storm. Knowledge of tropical cyclone impacts on an area help plan for future possibilities. Preparedness m ...
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Hurricane shutter Hurricane coverings, commonly known as shutters, are used in hurricane mitigation to protect houses and other structures from damage caused by storms. Hurricane shutters are used to prevent windows from being broken by flying objects during a s ...
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HurriQuake The HurriQuake nail is a construction nail designed by Ed Sutt for Bostitch, a division of Stanley Works, and patented in 2004. The features of the nail are designed primarily to provide more structural integrity for a building, especially agai ...
nail (for resisting hurricanes and earthquakes) *
Structural engineering Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and muscles' that create the form and shape of man-made structures. Structural engineers also must understand and cal ...
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Windstorm inspection A windstorm inspection, also referred to as a windstorm mitigation inspection, windstorm insurance inspection or wind mitigation inspection, is a kind of home inspection common in the coastal areas of the Southeastern United States. The purpose of ...


References

Notes


External links


house building in Northern Australia 2008 photographs.
{{DEFAULTSORT:Hurricane-Proof Building Building engineering Building Coastal construction Tropical cyclone preparedness Buildings and structures