Hurricane-proof building

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Tornadoes, cyclones, 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.

Contents

Storm surge considerations

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

Wind loading considerations

The foundation

A monolithic dome in Pensacola Beach, Florida, after Hurricane Dennis in 2005 Pensacola Beach, Florida after Hurricane Dennis in 2005.jpg
A monolithic dome in Pensacola Beach, Florida, after Hurricane Dennis in 2005

Wind acting on the roof surfaces of a building 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 of the building 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 destruction of the building. One example of pan roof systems can be found in this document from 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. [1] [2] Even stronger buildings result from monolithic dome construction. [3]

Monolithic dome

A monolithic dome is a structure cast in a one-piece form. The form may be permanent or temporary and may or may not remain part of the finished structure. Monolithic domes are a form of monolithic architecture.

Log house

A CAT 5 hurricane-proof log house is resistant to the winds up to 245 mph. Wall logs in such construction have to be made of [4] [5] glued laminated timber and all other components of the house have to be hurricane-resistant.

Log house type of house, built from wooden logs; much the same as a log cabin

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 smaller, more rustic log house, such as a hunting cabin in the woods, that may or may not have electricity or plumbing.

Glued laminated timber

Glued laminated timber, also called glulam, is a type of structural engineered wood product comprising a number of layers of dimensional lumber bonded together with durable, moisture-resistant structural adhesives. In North America, the material providing the laminations is termed laminating stock or lamstock.

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 can provide protection.

Doors can be blown into the house by wind, causing potential structural failure (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. Tapcons are used to fasten windows with the concrete structure surrounding.

Wood has a relatively high degree of flexibility, which can be beneficial under certain building stresses.

Reinforced concrete is a strong, dense material that, if used in a building that is designed properly, can withstand the destructive power of very high winds, and high-speed debris.

Regulation

After Hurricane Andrew in 1992 caused $16 billion in insured damage, the state of Florida 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. One important addition included with 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 adhesives and types of roofing. [6] [7] Florida also designated high velocity hurricane zones (i.e. High Velocity Hurricane Zone) with special requirements defined for Miami-Dade and Broward Counties. [8]

Hong Kong requires many structures to withstand winds from typhoons. [9]

Examples of cyclonic construction methods

Residential construction in Darwin Northern Australia

See also

Related Research Articles

Tallinn TV Tower

The Tallinn TV Tower is a free-standing structure with an observation deck, built to provide better telecommunication services for the 1980 Moscow Summer Olympics regatta event. It is located near the suburb Pirita, six km north-east of the Tallinn city center. With its 313 m (1030.2 ft), the TV Tower is the tallest building in Tallinn. The tower was officially opened on 11 July 1980. The viewing platform at a height of 170 metres was open to the public until 26 November 2007, when it was closed for renovation. Having been repaired, the tower began receiving visitors again on 5 April 2012. The building is administered by the public company Levira and is a member of the World Federation of Great Towers.

Storm cellar

A storm shelter or storm cellar is a type of underground bunker designed to protect the occupants from violent severe weather, particularly tornadoes. They are most frequently seen in the Midwest and Southeastern United States where tornadoes are generally frequent and the low water table permits underground structures.

Foundation (engineering) lowest and supporting layer of a structure

In engineering, a foundation is the element of a structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics in the design of foundation elements of structures.

Tilt up tilt up construction

Tilt-up,tilt-slab or tilt-wall is a type of building and a construction technique using concrete. Though it is a cost-effective technique with a shorter completion time, poor performance in earthquakes has mandated significant seismic retrofit requirements in older buildings.

Seismic retrofit

Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries and late 1970s for many other parts of the world, many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41 and the New Zealand Society for Earthquake Engineering (NZSEE)'s guidelines. These codes must be regularly updated; the 1994 Northridge earthquake brought to light the brittleness of welded steel frames, for example.

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 storm. Although the negative pressure caused by high velocity wind flowing over a building roof can cause the roof to fail with the building envelope intact, broken windows allow the air pressure to rise inside a building, creating an even greater pressure difference, and increasing the likelihood of roof failure.

Concrete masonry unit standard size rectangular block used in building construction

A concrete masonry unit (CMU) is a standard size rectangular block used in building construction. CMUs are some of the most versatile building products available because of the wide variety of appearances that can be achieved using concrete masonry units.

Concrete shell structure composed of a relatively thin shell of concrete

A concrete shell, also commonly called thin shell concrete structure, is a structure composed of a relatively thin shell of concrete, usually with no interior columns or exterior buttresses. The shells are most commonly flat plates and domes, but may also take the form of ellipsoids or cylindrical sections, or some combination thereof. The first concrete shell dates back to the 2nd century.

Insulating concrete form

Insulating concrete form or insulated concrete form (ICF) is a system of formwork for reinforced concrete usually made with a rigid thermal insulation that stays in place as a permanent interior and exterior substrate for walls, floors, and roofs. The forms are interlocking modular units that are dry-stacked and filled with concrete. The units lock together somewhat like Lego bricks and create a form for the structural walls or floors of a building. ICF construction has become commonplace for both low rise commercial and high performance residential construction as more stringent energy efficiency and natural disaster resistant building codes are adopted. ICFs may be used with frost protected shallow foundations (FPSF), the originator of which was the Swedish company Legalett. The first Legalett slab was designed and built in Kungälv, Sweden in 1983 and even had a rudimentary warm air heating system in pipes cast into the concrete slab. There are currently over 20 million square feet of Legalett Air-Heated Radiant Floor Systems installed worldwide. "

A tie, strap, tie rod, eyebar, guy-wire, suspension cables, or wire ropes, are examples of linear structural components designed to resist tension. It is the opposite of a strut or column, which is designed to resist compression. Ties may be made of any tension resisting material.

Formwork

Formwork is temporary or permanent molds into which concrete or similar materials are poured. In the context of concrete construction, the falsework supports the shuttering molds.

Hurricane preparedness Planning and actions to deal with a tropical cyclone strike

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 may involve preparations made by individuals as well as centralized efforts by governments or other organizations. Tracking storms during the tropical cyclone season helps individuals know current threats. Regional Specialized Meteorological Centers and Tropical Cyclone Warning Centers provide current information and forecasts to help individuals make the best decision possible.

Domestic roof construction the supporting structure of a roof, necessary for its stability

Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Such roofs are built with mostly timber, take a number of different shapes, and are covered with a variety of materials.

Lift slab construction

Lift slab construction is a method of constructing concrete buildings by casting the floor or roof slab on top of the previous slab and then raising (jacking) the slab up with hydraulic jacks. This method of construction allows for a large portion of the work to be completed at ground level, negating the need to form floor work in place. The ability to create monolithic concrete slabs makes the lift slab construction technique useful in quickly creating structures with repetitive form work, like parking ramps.

The term "tornado preparedness" refers to safety precautions made before the arrival of and during a tornado. Historically, the steps taken have varied greatly, depending on location, or time remaining before a tornado was expected. For example, in rural areas, people might prepare to enter an external storm cellar, in case the main building collapses, and thereby allow exit without needing rescue from the main building as in urban areas. Because tropical storms have spawned many tornadoes, hurricane preparations also involve tornadoes. The term "tornado preparedness" has been used by government agencies, emergency response groups, schools, insurance companies, and others.

WHH GT 18

WHH GT 18 is a standard residential high-rise building type in East Berlin. It was developed by architects Helmut Stingl and Joachim Seifert between 1969 and 1971 using large panel construction for mixed-use housing in Berlin.

Hip roof type of roof where all sides slope downwards to the walls

A hip roof, hip-roof or hipped roof, is a type of roof where all sides slope downwards to the walls, usually with a fairly gentle slope. Thus a hipped roof house has no gables or other vertical sides to the roof.

Signature Tower is a proposed skyscraper in Jakarta, Indonesia. With a height of 638 m (2,093 ft) upon completion, it would become the sixth tallest skyscraper in the world.

A windpost is a structural item used in the design and construction of masonry walls to increase lateral wall stability and protect them against damage from horizontal forces imposed by wind pressure, crowd or handrail loads. They are normally constructed from mild steel channel sections, supported at the head and the foot between floor slab levels and/or the principal steelwork sections forming the structural frame of the building. In cavity walls, the windpost will typically be fixed into the inner and outer leafs of the wall by specialist fixings and fastenings at regular intervals along its length. The windposts will be spaced along the walls of the building at regular intervals as calculated by the engineer to suit the required loadings.

References

Notes

  1. http://www.stanford.edu/~scheulen/.../StructuralMechanicsFinalReport.pdf
  2. http://www.ewb-uk.org/system/files/Marek+Kubik+report.pdf
  3. http://www.monolithic.com/stories/building-survivability-the-strength-of-the-monolithic-dome
  4. http://eccobauer.com/en/hurricane-proof-log-housef
  5. https://en.wikipedia.org/wiki/Glued_laminated_timber
  6. "Fla. Building Codes, Revamped Since Andrew, Still Being Worked". Insurance Journal. 2007-05-18. Retrieved 2016-10-09.
  7. Tsikoudakis, Mike. "Hurricane Andrew prompted better building code requirements – Business Insurance". Business Insurance. Retrieved 2016-10-09.
  8. "Changes to the Wind Speed Maps and Wind Design – 2010 Florida Building Codes" (PDF). Retrieved Oct 9, 2016.
  9. Phil Muncaster (September 30, 2013). "Hong Kong's data centres stay high and dry amid Typhoon Usagi". The Register. Retrieved January 5, 2015.