Coral Reefs + the Burj Khalifa
REACH ISSUU CORAL REEFS Erosion and Coral Reefs Coral reefs also benefit humans by protecting shorelines from the full onslaught of storm-driven waves. Humans, however, are responsible for causing severe damage to coral reefs. Reefs are often destroyed by collectors, who use coral to create jewelry, and fisherman, who use poison or dynamite to catch fish. Because corals need sunlight and sediment-free water to survive, water
pollution poses a grave danger. Oil spills, the dumping of sewage wastes, and the runoff of soil and agricultural chemicals such as pesticides all threaten the delicately balanced ecosystem of coral reefs. Read more: Coral - humans, body, water, Earth, life, plants, form, animals, waves, surface, Biology of corals, Formation of coral reefs http://www.scienceclarified.com/CiCo/Coral.html#ixzz0dpBURpfC http://www.scienceclarified.com/Ci-Co/Coral.html
Monitoring Network, an international environmental monitoring organization, issued the report with data gathered from scientists around the globe. According to the report, the world has lost 27 percent of its coral reefs. Some of those reefs can never be recovered, while some could possibly come back. Most of the damaged reefs were found in the Persian Gulf, the Indian Ocean, the waters around Southeast and East Asia, and the Caribbean and adjacent Atlantic. The report pointed out that global warming was the biggest threat facing coral reefs, followed by water pollution, sediment from coastal development, and destructive fishing techniques (such as using dynamite and cyanide). If nothing is done to stop the destruction caused by humans, 60 percent of the world's coral reefs will disappear by 2030. http://www.scienceclarified.com/Ci-Co/Coral.html
Healthy coral reefs have rough surfaces and complex structures that dissipate much of the force of incoming waves; this buffers shorelines from currents, waves, and storms, helping to prevent loss of life, property damage, and erosion. [a] Up to 90 percent of the energy from wind-generated waves is absorbed by reefs, based on the physical and ecological characteristics of the reef and the abundance of the adjacent seagrass and mangrove ecosystems. [b] In fact, coastlines protected by reefs are more stable, in terms of erosion, than those without. [c] Reefs are also a source of sand in natural beach replenishment. [d]
http://coralreef.noaa.gov/aboutcorals/values/coastalprotection/
Environmental threats Main article: Environmental threats to the Great Barrier Reef
Sea temperature and bleaching of the Great Barrier Reef
The most significant threat to the Great Barrier Reef is climate change.[49][50] Mass coral bleaching events due to rising ocean temperatures occurred in the summers of 1998, 2002 and 2006,[51] and coral bleaching will likely become an annual occurrence.[52] Climate change has implications for other forms of life on the Great Barrier Reef as well - some fish's preferred temperature range lead them to seek new areas to live, thus causing chick mortality in seabirds that prey on the fish. Climate change will also affect the population and available habitat of sea turtles.[53] Another key threat faced by the Great Barrier Reef is pollution and declining water quality. The rivers of north eastern Australia provide significant pollution of the Reef during tropical flood events with over 90% of this pollution being sourced from farms.[54] Farm run-off is polluted as a result of overgrazing and excessive fertiliser and pesticide use. Due to the range of human uses made of the water catchment area adjacent to the Great Barrier Reef, water quality has declined owing to the sediment and chemical runoff from farming, and to loss of coastal wetlands which are a natural filter.[55][56][57] It is thought that the mechanism behind poor water quality affecting the reefs is due to increased light and oxygen competition from algae.[58]
Crown-of-thorns starfish
The crown-of-thorns starfish is a coral reef predator which preys on coral polyps. Large outbreaks of these starfish can devastate reefs. In 2000, an outbreak contributed to a loss of 66% of live coral cover on sampled reefs in a study by the CRC Reefs Research Centre.[59] Outbreaks are believed to occur in natural cycles, exacerbated by poor water quality and overfishing of the starfish's predators.[59][60] The unsustainable overfishing of keystone species, such as the Giant Triton, can
cause disruption to food chains vital to life on the reef. Fishing also impacts the reef through increased pollution from boats, by-catch of unwanted species (such as dolphins and turtles) and reef habitat destruction from trawling, anchors and nets.[61] As of the middle of 2004, approximately one-third of the Great Barrier Reef Marine Park is protected from species removal of any kind, including fishing, without written permission.[62] Other threats to the Great Barrier Reef include shipping accidents, oil spills, and tropical cyclones.[63] Skeletal Eroding Band, a disease of bony corals caused by the protozoan Halofolliculina corallasia, affects 31 species of corals from six families on the reef.[64] http://en.wikipedia.org/wiki/Great_Barrier_Reef#Environmental_threats
Coral reefs, with their vast diversity of invertebrate, vertebrate and algal species, have undoubtedly been subjected to natural disturbance since their appearance millions of years ago. Anthropogenic disturbance has been a factor affecting reefs for a fraction of that time, yet in terms of overall impact, may be of greater concern. Data on habitat destruction, pesticide and heavy metal accumulation, nutrient loading, sedimentation, runoff and related impacts of man's activities indicate that many coastal reefs are endangered by these processes through alterations in animalalgal symbioses, shifts in competitive interactions, direct mortality, reproductive failure, and insufficient recruitment. The death of corals critically affects reef communities, as corals provide an important trophic link as well as the main habitat structure. While natural disturbance is an important factor affecting reef interactions, species diversity and evolution, chronic anthropogenic disturbances combined with unsuitable environments for recovery, are of great concern. Physiological stress can be measured in corals in addition to outright
mortality, allowing the impacts of specific disturbances to be assessed. Sufficientdata for distinguishing real problems from temporal variability are becoming available, allowing scientists to focus on practical solutions to problems in coral reef management and preservation. http://icb.oxfordjournals.org/cgi/content/abstract/33/6/524
a reef whose surface lies above the high-tide mark, either by uplift or by eustatic regression of the sea (which is determined by ice sheet–sea level relations), is subject to planing by marine erosion. If planing off is complete, a flat-topped submerged platform results. If subsidence or eustatic submergence intervenes, a wave-cut terrace is left around the reef. http://www.britannica.com/facts/5/540904/erosion-as-discussed-in-coral-reef-geology
Carbon emissions are undermining coral reefs' ability to repair themselves. They need calcium carbonate to mend holes created by sea creatures and erosion, but the more C[O.sub.2] there is in the atmosphere, the more it's absorbed by the sea, which lowers the water's pH and reduces levels of dissolved calcium carbonate. Scientists believe that before the Industrial Revolution, more than 98 per cent of corals lived in water with enough calcium carbonate. Now, nearly half live in areas with dangerously low levels of the compound. http://findarticles.com/p/articles/mi_hb3120/is_11_80/ai_n31011424/?tag=content;col1
A study published in this week's issue of PNAS has shown that coral reefs in the waters off Panama and Galapagos, which live in a naturally acidic and high CO2 environment, contain dangerously low percentages of scement to hold them in place. The researchers believe that these reefs are a vision into the future of reefs worldwide, since their environment replicates the expected increased in acidity and CO2. Oceans have already absorbed about one-third of all carbon dioxide released into the atmosphere since the industrial revolution.
http://news.mongabay.com/2008/0728-hance_reefs.html this link had even more helpful information
Fish living in Coral Reefs Small fish inhabit the many holes and crevices on this portion of the reef, and many larger fish including sharks, jacks, barracudas and tunas patrol the buttresses and grooves in search of food (Barnes, R.D., 1987; Lalli and Parsons, 1995; Sumich, 1996). http://coris.noaa.gov/about/what_are/
Coral reefs are some of the most diverse and valuable ecosystems on Earth. Coral reefs support more species per unit area than any other marine environment, including about 4,000 species of fish, 800 species of hard corals and hundreds of other species. Scientists estimate that there may be another 1 to 8 million undiscovered species of organisms living in and around reefs (Reaka-Kudla, 1997). This biodiversity is considered key to finding new medicines for the 21st century. Many drugs are now being developed from coral reef animals and plants as possible cures for cancer, arthritis, human bacterial infections, viruses, and other diseases. http://oceanservice.noaa.gov/education/kits/corals/coral07_importance.html
ecology The Great Barrier Reef supports a diversity of life, including many vulnerable or endangered species, some of which may be endemic to the reef system.[30][31]
Green sea turtle on the Great Barrier Reef
Thirty species of whales, dolphins, and porpoises have been recorded in the Great Barrier Reef, including the dwarf minke whale, Indo-Pacific humpback dolphin, and the humpback whale. Large populations of dugongs live there.[32] [33][31]
Six species of sea turtles come to the reef to breed – the green sea turtle, leatherback sea turtle, hawksbill turtle, loggerhead sea turtle, flatback turtle, and the olive ridley. The green sea turtles on the Great Barrier Reef have two genetically distinct populations, one in the northern part of the reef and the other in the southern part.[34] Fifteen species of seagrass in beds attract the dugongs and turtles,[32] and provide a habitat for fish.[35] The most common genera of seagrasses are Halophila and Halodule.[36] Saltwater crocodiles live in mangrove and salt marshes on the coast near the reef.[37] Nesting has not been reported, and the salt water crocodile population in the GBRWHA is wide-ranging and with a low population density.[38] Around 125 species of shark, stingray, skates or chimera live on the reef.[39][40] Close to 5,000 species of mollusc have been recorded on the reef, including the giant clam and various nudibranchs and cone snails.[32] Forty-nine species of pipefish and nine species of seahorse have been recorded.[38] At least seven species of frog can be found on the islands.[41] 215 species of birds (including 22 species of seabirds and 32 species of shorebirds) are attracted to the reef or nest or roost on the islands,[42] including the white-bellied sea eagle and roseate tern.[32] Most nesting sites are on islands in the northern and southern regions of the Great Barrier Reef, with 1.4-1.7 million birds using the sites to breed.[43][44] The islands of the Great Barrier Reef also support 2,195 known plant species; three of these are endemic. The northern islands have 300-350 plant species which tend to be woody, whereas the southern islands have 200 which tend to be herbaceous; the Whitsunday region is the most diverse, supporting 1,141 species. The plant species are spread by birds.[41] Seventeen species of sea snake live on the Great Barrier Reef. They take three or four years to reach sexual maturity and are long-lived but with low fertility. They are usually benthic, but the species that live on the soft sediment differ from those that live on the reefs themselves. They live in warm waters up to 50 metres (164 ft) deep and are more common in the southern than in the northern part of the reef. None of the sea snakes found in the Great Barrier Reef World Heritage Area are endemic to the reef, nor are any of them endangered.[38]
More than 1,500 species of fish live on the reef, including the clownfish, red bass, red-throat emperor, and several species of snapper and coral trout.[32] Forty-nine species are known to mass spawn, with eighty-four other species found on the reef spawning elsewhere in their range.[45] There are at least 330 species of ascidians found on the reef system, ranging in size from 1 mm-10 cm (0.04–4 in) in diameter. Between 300-500 species of bryozoans are found on the reef system.[40] Four hundred species of corals, both hard corals and soft corals are found on the reef.[32] The majority of these spawn gametes, breeding in mass spawning events that are controlled by the rising sea temperatures of spring and summer, the lunar cycle, and the diurnal cycle. Reefs in the inner Great Barrier Reef spawn during the week after the full moon in October, but the outer reefs spawn in November and December.[46] The common soft corals on the Great Barrier Reef belong to 36 genera.[47] Five hundred species of marine algae or seaweed live on the reef,[32] including thirteen species of the genus Halimeda, which deposit calcareous mounds up to 100 metres (110 yd) wide, creating miniecosystems on their surface which have been compared to rainforest cover.[48] http://en.wikipedia.org/wiki/Great_Barrier_Reef#Environmental_threats
There are also many species of fish that live in the Great Barrier Reef (over 140 species). Some of them are very large while others are very small. Some of the larger animals are the Great White Shark-a large (normally 600 IBS!) that is featured in a movie called Jaws, another is the hammerheada large ,wide headed predator. some of the smaller ones are the White Sea Urchin, Basket Fish, Four
Eyed Butter Fish, and the Soldier Fish. To learn more about sea life, go to Coral Renters, a page about sea creatures that live in reefs throughout the world http://library.thinkquest.org/6416/great.htm
Many fish travel in packs to protect themselves from the many predators hiding in the coral caves. A few of these ever present predators are the infamous eels, Great White sharks, and including several types of sharks. These sharks have a hunger for the many small & large fish in the surrounding areas. These sharks include the Gray Tipped shark, and the many Blue sharks. The camouflage that the fish have adapted to using in coral reefs protect them from the deadly sharks. One type of fish the Scorpion Fish uses camoflauge for protection. A few fish such as the "Milk Fish" as the name was dubbed to it, for when the fish is squeezed or bitten it lets a milky substance from its skin that is annoying and distasteful to predators. Though the coral reef has many fish that are well defended and hidden predators still find food in the reefs. Several small types of fish who rely on speed for protection, soon learn that eels have also evolved to be quicker and more efficient hunters. Fish tend to live in crevices and only come out in groups or "schools" of fish because the more eyes the more likely a predator will be spotted and avoided than if 3 fish were in a group instead of 50 or 60. Several animals that are not fish such as lobster and crabs live in coral reefs. The Flamingo Tongue Snail, the Red Coral shrimp,the Ghost Crabs, the Sand Shrimp and the Moon Snails all live in the coral. These animals also have bright colors like the other fish. A few other creatures that arent fish that live in the coral reefs are the White Sea Urchin , the Basket Starfish, and the Rock Crab all live in the coral reefs. Jellysifh also live in certain areas of coral reefs. http://library.thinkquest.org/6416/coral_renters.htm
Formation of Coral Reefs
Reef formation The prime reef builders are the stony or hard corals (subphylum Anthozoa). Reefs are formed by the skeletons of the tiny coral polyps. A coral polyps consist of a fleshy sack with a ring of tentacles which sits in a limestone skeletal case, secreted by the polyp. Reef-building corals have evolved an indispensable symbiotic relationship with a type of brown algae called zoxanthellae (Symbiodinium microadriaticum). Millions of these single-celled algae are living as symbionts within their tissues (hermatypic corals). Zooxanthellae produce sugars and oxygen through photosynthesis thus helping the coral in the process of producing limestone or calcium carbonate. Corals grow up to three times faster with the help of the zooxanthellae. Zooxanthellae give the corals their characteristic greenish color. A change of environmental conditions such as higher temperatures or a change in salinity but also disease can cause the polyps to expel the algae. The coral becomes totally white (= coral bleaching). If the coral regains some algae it might survive, but bleaching can be irreversible and then the coral dies.
http://www.starfish.ch/reef/reef.html This website has great terms graphics maps etc
Corals are a group of small, tropical marine animals that attach themselves to the seabed and form extensive reefs, commonly in shallow, warm-water seas. These reefs are made up of the calcium-carbonate (limestone) skeletons of dead coral animals. Coral reefs form the basis of complex marine food webs that are richer in species than any other ecosystem (community of plants and animals). Read more: Coral - humans, body, water, Earth, life, plants, form, animals, waves, surface, Biology of corals, Formation of coral reefs http://www.scienceclarified.com/CiCo/Coral.html#ixzz0dp9fmjDz
http://www.scienceclarified.com/Ci-Co/Coral.html
Coral reefs are formed mainly by the hard skeletons of corals and the limestone deposits of coralline algae and other marine animals. Reefs grow upward as generations of corals produce limestone skeletons, die, and become the base for a new generation. Coral reefs lie in a zone of water 30°N to 30°S of the equator. Reef-forming coral animals flourish only in water under 100 feet (30 meters) deep and warmer than 72°F (22°C). Coral reefs are classified into three main types. Fringing reefs grow close to the shore of a landmass, extending out like a submerged platform. Barrier reefs also follow a coastline, but are separated from it by wide expanses of water. Atolls are ring-shaped reefs surrounding lagoons. The Great Barrier Reef of northeast Australia is the largest structure on Earth created by a living thing. It is 10 to 90 miles (16 to 145 kilometers)
Read more: Coral - humans, body, water, Earth, life, plants, form, animals, waves, surface, Biology of corals, Formation of coral reefs http://www.scienceclarified.com/CiCo/Coral.html#ixzz0dpAWvRuo http://www.scienceclarified.com/Ci-Co/Coral.html
Appearing as solitary forms in the fossil record more than 400 million years ago, corals are extremely ancient animals that evolved into modern reef-building forms over the last 25 million years. Coral reefs are unique (e.g., the largest structures on earth of biological origin) and complex systems. Rivaling old
growth forests in longevity of their ecological communities, well-developed reefs reflect thousands of years of history (Turgeon and Asch, in press). http://coris.noaa.gov/about/what_are/
Coral reefs form in shallow water that is at a nice warm temperature. Coral forms near land and in the tropics. They are very rich in life. Clown fish and many other organisms can be found here. Coral reefs are very tall and can stretch for miles. The coral is formed by polyps, and when they die they leave behind a stony limestone structure. Only the coral that are hard can form coral. It is very vulnerable to death. If it is kicked, even slightly, it will most likely die. Coral can also die by turning white. There are three types of coral: fringing coral, barrier coral, and coral atolls. Fringing coral forms along continental shelves and coast lines. Barrier coral runs parallel to the shorelines and are separated by lagoon. Coral atolls grow on top of old sunken volcanoes. Coral reefs are a very important ecosystem. They contain a lot of rich resources such as new medicines. They are very delicate and even a slight temperature change can stress them. Chemicals kill them and can block the needed sunlight out. Coral reefs are usually found in bright colors such as: orange, tan, yellow, purple, and green. Coral reefs will be wiped out very shortly so we really need to protect them. http://library.thinkquest.org/05aug/00183/Coral%20Reef%20Formation.htm
Stony corals are a remarkable group of animals that inhabit tropical marine waters around the world and form vast colonies known as coral reefs. Coral reefs often resemble rock formations or even plants but such resemblances are only superficial. Coral reefs are in fact made up of many tiny animals known as coral polyps. Each coral polyp is an individual animal and the individual polyps coexist as part of a larger colony of polyps. http://animals.about.com/b/2007/10/30/how_do_coral_reefs_form.htm Coral reefs are extremely diverse and are considered to be one of the most multifunctional and economically important coastal marine ecosystems. These reefs are productive shallow water marine ecosystems and are considered to be one of the greatest natural treasures of the world (Cesar, Herman). They are composed of lime skeletons, which are formed through successive growth and deposition of reef-building corals and coralline algae. Each reef-building coral contains many coral polyps and symbiotic algae called zooxanthellae that live within the coral tissues. Each coral polyp is an individual coral, which withdraws into the coral skeleton during the day. The zooxanthellae photosynthesize organic compounds from sunlight and these compounds are used for food for the coral (Davidson, Osha Gray). It is considered a mutualistic
symbiotic relationship because the coral benefits from the algae, but the algae also benefit from the coral. The coral produce carbon dioxide and nitrogen as a waste product, which serves as a food source for the zooxanthellae. This mutualistic relationship will not allow the coral or zooxanthellae to live without each other. Because of this relationship with the algae the corals have restricted environments. The symbiotic algae require sunlight for photosynthesis and can be easily destroyed by effects such as sedimentation, thereby killing the entire coral (Miller, Stephen). These ecosystems are filled with the highest densities of animals on the globe and surpass even the tropical rainforests in terms of diversity (Spalding et al). Because of their immense diversity, they are of great interest to scientists, pharmaceutical companies, health professionals, and others. http://jrscience.wcp.muohio.edu/fieldcourses03/PapersMarineEcologyArticles/AnthropogenicEffects onCor.html
PICTURES
http://washingtonson.blogspot.com/2008_02_21_archive.html
http://my.opera.com/tatora/blog/index.dml/tag/graphic%20design
http://www.reefteach.com.au/Clown_Fish.htm
http://www.coexploration.org/bbsr/coral/assets/images/satellite.jpg
http://www.coexploration.org/bbsr/coral/html/body_reef_formation.htm
http://news.mongabay.com/2008/0728-hance_reefs.html
To read more about coral reefs: http://www.noaa.gov/ http://life.bio.sunysb.edu/marinebio/coralreef.html
BURJ KHALIFA Why was the Burj Dubai built? Broadcast and Communications Floors The top four floors have been reserved for communications and broadcasting. These floors occupy the levels just below the spire.
http://www.burjkhalifa.ae/the-tower/structure.aspx
World Records At over 800 metres (2625 feet) and more than 160 stories, Burj Khalifa holds the following records:
• Tallest building in the world
• Tallest free-standing structure in the world
• Highest number of stories in the world
• Highest occupied floor in the world
• Highest outdoor observation deck in the world
• Elevator with the longest travel distance in the world
• Tallest service elevator in the world
http://www.burjkhalifa.ae/the-tower/structure.aspx
At The Top, Burj Khalifa Observation deck on level 124
At.mosphere, Burj Khalifa Fine dining restaurant on level 122
The Residence 900 Burj Khalifa residences
The Corporate Suites 37 office floors
Armani Hotel Dubai 160 guestrooms and suites
Armani Residences Dubai 144 private residences
The Park
11 hectares park, 6 water features 3000 underground parking spaces
The Club 4-storey fitness and recreation annex
http://www.burjkhalifa.ae/the-tower/fact-figures.aspx
Highest occupied floor Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest continually occupied floor within the building. Maintenance areas are not included.
http://www.burjkhalifa.ae/the-tower/fact-figures.aspx
Concourse level to level 8 and level 38 and 39 will feature the Armani Hotel Dubai. Levels 9 to 16 will exclusively house luxurious one and two bedroom Armani Residences. Floors 45 through 108 are private ultra-luxury residences. The Corporate Suites occupy fill most of the remaining floors, except for level 122 which houses a restaurant and level 124, the tower's public observatory. For the convenience of home owners, the tower has been divided in to sections with exclusive Sky Lobbies on Levels 43, 76 and 123 that feature state-of-the-art fitness facilities including a Jacuzzis on Level 43 and 76. The Sky Lobbies on 43 and 76 additionally house swimming pools and a recreational room each that can be utilized for gatherings and lifestyle events. Offering an unparalleled experience, both pools open to the outside offering residents the option of swimming from inside to the outside balcony. Other facilities for residents include a Residents' Library, and Burj Khalifa Gourmet Market, a gourmet convenience store and meeting place for the residents. Valet parking will be provided for guests and visitors
http://www.burjkhalifa.ae/the-tower/design.aspx#wind
BURJ KHALIFA'S GRAND VISION World's tallest building. A living wonder. Stunning work of art. Incomparable feat of engineering. Burj Khalifa is all that. In concept and execution, Burj Khalifa has no peer. More than just the world's tallest building, Burj Khalifa is an unprecedented example of international cooperation, symbolic beacon of progress, and an emblem of the new, dynamic and prosperous Middle East. It is also tangible proof of Dubai's growing role in a changing world. In fewer than 30 years, this city has transformed itself from a regional centre to a global one. This success was not based on oil reserves, but on reserves of human talent, ingenuity and initiative. Burj Khalifa embodies that vision.
Mr Mohamed Alabbar, Chairman, Emaar Properties, said: "Burj Khalifa goes beyond its imposing physical specifications. In Burj Khalifa, we see the triumph of Dubai's vision of attaining the seemingly impossible and setting new benchmarks. It is a source of inspiration for every one of us in Emaar. The project is a declaration of the emirate's capabilities and of the resolve of its leaders and people to work hand in hand on truly awe-inspiring projects. Emaar had but one inspiration, the unflagging enthusiasm set in motion by His Highness Sheikh Mohammed Bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE and Ruler of Dubai, who inspires us to reach for the stars.
http://www.burjkhalifa.ae/language/en-us/the-tower/vision.aspx
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
BROADCAST AND COMMUNICATION TALLEST BUILDING IN THE WORLD & OTHER RECORDS DINING HOTEL APARTMENTS CORPERATE SUITES CLUB OBSERVATION TOWER GOURMET MARKET SOURCE OF INSPERATION
What was involved in the construction process? Burj Khalifa Construction Timeline Excavation started
January 2004 Piling started
February 2004 Superstructure started
March 2005 Level 50 reached
June 2006 Level 100 reached
January 2007 Level 110 reached
March 2007 Level 120 reached
April 2007 Level 130 reached
May 2007 Level 141 reached - world's tallest building
July 2007
Level 150 reached - world's tallest free-standing structure
September 2007 Level 160 reached - world's tallest man-made structure
April 2008 Completion of spire - Burj Khalifa tops out
January 2009 Exterior cladding competed
September 2009 Official launch ceremony
January 2010
http://www.burjkhalifa.ae/the-tower/construction.aspx
CONSTRUCTION TEAM
Burj Khalifa was truly an international collaboration between more than 30 on-site contracting companies from nations around the world.
At the peak of construction, over 12,000 workers and contractors were on site everyday, representing more than 100 nationalities
http://www.burjkhalifa.ae/the-tower/construction.aspx
Another obstacle that had to be overcome during the construction of the Burj Dubai was the difficulty of pumping concrete at such great heights and was also challenging due to the extreme high temperatures in Dubai. Due to the high temperatures it was critical that the concrete’s consistency be just right. A variance could cause cracks in the concrete that could jeopardize the stability of the entire tower. To overcome this obstacle, high performance concrete was used and pumped and poured during night hours when it is cooler. Each new batch of concrete was tested to ensure it could withstand the weight pressures of the tower. The Burj Dubai is the world record holder for the highest concrete pump height.
Another obstacle that needed to be overcome was communication, as the tower grew taller and taller. Construction crews ran into a problem with the walkie-talkies they were using for communication when they got past the 30th floor. The walkie-talkies started experiencing delays or no reception at all.
Communication is critical to coordinate the crane operators and other builders working on the building. The communication problem was solved through the use of a wireless mesh network. The walkie-talkies now make use of ROIP and VOIP features. Project managers also make use of computer technology to help communicate the planning process through animation and graphing to help the workers and subcontractors understand various stages of the construction process.
http://www.burjofdubai.com/obstacles-during-the-burj-dubai-construction/
. At times, new floors were being added almost every three days. During the busiest construction periods, some 12,000 people worked at the tower each day, according to Emaar. Low-wage migrant workers from the Indian subcontinent provided much of the muscle http://www.post-gazette.com/pg/10026/1025931-37.stm
The Dynamic Tower will feature 80 floors that rotate—you can see the sun rise and set from the same room. Choosing the location for his "Jetsons"-worthy creation was easy, says architect David Fisher. "Dubai is the city of the future." Bill Baker structural Engineer © 2008
The architecture features a triple-lobed footprint, an abstraction of the Hymenocallis flower. The tower is composed of three elements arranged around a central core. The modular, Y-shaped structure, with setbacks along each of its three wings provides an inherently stable configuration for the structure and provides good floor plates for residential. Twenty-six helical levels decrease the cross section of the tower incrementally as it spirals skyward.
The central core emerges at the top and culminates in a sculpted spire. A Y-shaped floor plan maximizes views of the Arabian Gulf. Viewed from the base or the air, Burj Khalifa is evocative of the onion domes prevalent in Islamic architecture.
http://www.burjkhalifa.ae/the-tower/design.aspx#wind
FOUNDATION The superstructure is supported by a large reinforced concrete mat, which is in turn supported by bored reinforced concrete piles. The design was based on extensive geotechnical and seismic studies. The mat is 3.7 meters thick, and was constructed in four separate pours totaling 12,500 cubic meters of concrete. The 1.5 meter diameter x 43 meter long piles represent the largest and longest piles conventionally available in the region. A high density, low permeability concrete was used in the foundations, as well as a cathodic protection system under the mat, to minimize any detrimental effects form corrosive chemicals in local ground water.
http://www.burjkhalifa.ae/language/en-us/the-tower/structure.aspx
PODIUM The podium provides a base anchoring the tower to the ground, allowing on grade access from three different sides to three different levels of the building. Fully glazed entry pavilions constructed with a suspended cable-net structure provide separate entries for the Corporate Suites at B1 and Concourse Levels, the Burj Khalifa residences
http://www.burjkhalifa.ae/language/en-us/the-tower/structure.aspx
STRUCTURAL SYSTEM In addition to its aesthetic and functional advantages, the spiraling “Y” shaped plan was utilized to shape the structural core of Burj Khalifa. This design helps to reduce the wind forces on the tower, as well as to keep the structure simple and foster constructability. The structural system can be described as a “buttressed core”, and consists of high performance concrete wall construction. Each of the wings buttress the others via a six-sided central core, or hexagonal hub. This central core provides the torsional resistance of the structure, similar to a closed pipe or axle. Corridor walls extend from the central core to near the end of each wing, terminating in thickened hammer head walls. These corridor walls and hammerhead walls behave similar to the webs and flanges of a beam to resist the wind shears and moments. Perimeter columns and flat plate floor construction complete the system. At mechanical floors, outrigger walls are provided to link the perimeter columns to the interior wall system, allowing the perimeter columns to participate in the lateral load resistance of the structure; hence, all of the vertical concrete is utilized to
support both gravity and lateral loads. The result is a tower that is extremely stiff laterally and torsionally. It is also a very efficient structure in that the gravity load resisting system has been utilized so as to maximize its use in resisting lateral loads. As the building spirals in height, the wings set back to provide many different floor plates. The setbacks are organized with the tower’s grid, such that the building stepping is accomplished by aligning columns above with walls below to provide a smooth load path. As such, the tower does not contain any structural transfers. These setbacks also have the advantage of providing a different width to the tower for each differing floor plate. This stepping and shaping of the tower has the effect of “confusing the wind”: wind vortices never get organized over the height of the building because at each new tier the wind encounters a different building shape.
http://www.burjkhalifa.ae/language/en-us/the-tower/structure.aspx
SPIRE The crowning touch of Burj Khalifa is its telescopic spire comprised of more than 4,000 tons of structural steel. The spire was constructed from inside the building and jacked to its full height of over 200 metres (700 feet) using a hydraulic pump. In addition to securing Burj Khalifa's place as the world's tallest structure, the spire is integral to the overall design, creating a sense of completion for the landmark. The spire also houses communications equipment.
http://www.burjkhalifa.ae/language/en-us/the-tower/structure.aspx
How does a tall building like the Burj Dubai maintain stability? Burj Dubai has been renamed to Burj Khalifa. The official height is:
828 m | 2716 feet http://www.burjdubaiskyscraper.com/
The architectural firm of Skidmore, Owings and Merrill used a series of design models and wind tunnel tests that resulted in substantial reductions in building motion and wind loads. Altering the shape and widths of the floors helped to reduce wind shear forces. The tower’s foundation is a concrete podium weighing 110,000 tons and consisting of 192 piles that are buried 164 meters deep. The large foundation is to prevent the tower from sinking into the sand. The frame of the building is made of structurally reinforced concrete and a steel spire. To manage wind loads, a buttressed core system was used with 3 wings forming a y-shape that help to brace the core structure. The design helps to distribute the weight of the tall tower.
http://www.burjofdubai.com/obstacles-during-the-burj-dubai-construction/
. To support the tower’s record heights and slim footprint, he developed the “buttressed core” [2] structural system, consisting of a hexagonal core reinforced by three buttresses that form a Y shape. This innovative system allows the structure to support itself both laterally and torsionally. It also eliminates the need for column transfers, and moves loads in a smooth path from the tower’s spire into its foundations
http://en.wikipedia.org/wiki/William_F._Baker_(engineer)
Over 40 wind tunnel tests were conducted on Burj Khalifa to examine the effects the wind would have on the tower and its occupants. These ranged from initial tests to verify the wind climate of Dubai, to large structural analysis models and facade pressure tests, to micro-climate analysis of the effects at terraces and around the tower base. Even the temporary conditions during the construction stage were tested with the tower cranes on the tower to ensure safety at all times. Stack effect or chimney effect is a phenomenon that effects super-tall building design, and arises from the changes in pressure and temperature with height. Special studies were carried on Burj Khalifa to determine the magnitude of the changes that would have to be dealt with in the building design.
http://www.burjkhalifa.ae/the-tower/design.aspx#wind