Burj Khalifa Tower in Dubai - Research Paper Example

Burj Khalifa Tower in Dubai Burj Khalifa Tower in Dubai Introduction Over the buildings constructed during thelast 100 years, the Burj Khalifa at Dubai holds a special significance because of the sheer size and magnitude of the piece. It is considered not only a jewel of Dubai but also a piece of art that continues to inspire both architectural and structural design engineers in the manner in which this building was conceived and constructed. This article seeks to shed light on a number of aspects that went into the making of this wonderful piece of architecture. Source: A view of the Burj Khlaifa Project, Subramanian N, 2010 The design The Burj Khalifa is also referred to as ‘A Living Wonder’ or a ‘Vertical City’. Located in the heart of Dubai, this building is considered one of the tallest structures in the world. (Lego Architecture, 2010) Emaar Properties PJSC was the chief promoter of this grand structure while the architects were Skidmore, Owings & Merill LLP (SOM), a company based in Chicago. (Lego Architecture, 2010) The two persons at the helm of this design were Adrian Smith and Bill Baker who were the architect and chief structural engineer respectively. The task of building the world’s tallest structure was entrusted to Owings & Merill because of their vast experience in creating such huge if not similar structures like the Seara Tower and the John Hancock Center. (Lego Architecture, 2010) Around 90 designers and engineers worked in close synergy to create this monumental piece which marvelled not only in size but also reflected the cultural and religious sentiment of the region. The Style The Burj Khalifa at 828 metres infused a mix of modern 21st century architecture while still retaining the finer symbolic aspects of traditional Islamic architecture. Classified as a Supertall skyscraper, reflective glazing aluminium and textured stainless steel was used significantly while the construction was carried out using reinforced concrete and steel. The project began in 2004 and was completed by 2010. (Lego Architecture, 2010) There were more than 160 stories in this meteoric building with the floor area measured at 5.67 million square feet. The tower was inaugurated by His Highness Sheikh Mohammed Bin Rashid Al Maktoum Vice President and Prime Minister of UAE and also the ruler of Dubai. (Lego Architecture, 2010) Owings and Merill LLP were shortlisted from among a team of five international competitors to work on the Burj Khalifa. To their credit the Haj Terminal at Jeddah Airport and the National Commercial bank were works that were created by Owings and Merill and which had a significant presence of Islamic architecture in its style. The shape of this structure was inspired by the regional desert flower called Hymenocallis. (Lego Architecture, 2010) Source: The Hymenocallis Flower, Lego Architecture, 2010 This flower has petals in a triangular shape joined at the centre. The building has a similar pattern with stories rotated alternatively so that this Y shaped plan allowed for a maximum view at the same time facilitating good lighting conditions. (Novak C Lawrence, 2010) In the plan view of the structure, the tip of this structure elicits the traditional dome shaped image which is a recurring theme of traditional Islamic architecture. Economic considerations The statistics of materials and man-hours used in the construction of Burj Khalifa is impressive. Close to 330,000 cubic metres of concrete, 39000 tonnes of reinforcing steel, 103,000 square metres of glass surfacing and 15, 5000 square metres of stainless steel were used for its construction. A total of 22 million man-hours were consumed in building this masterpiece. The space features of Burj Khalifa stack up to 526,000 square metres of built area, 170,000 square metres of residential area, 28,000 square metres of business and office establishments. (Subramanian N, 2010) The rest of the space is taken up for accommodating luxury hotels. The building has 57 numbers of non-stop shuttle elevators and 8 escalators. Travelling at a speed of 10 metres/sec these are considered to be the world’s fastest elevators. The service elevator has a capacity of 5500 kilograms. Close synergy between the different departments like mechanical, electrical, plumbing, architectural, structural wing along with other consultants have meant that the execution of project had been meticulously planned. The water system of the building accounts for 946,000 litres of water on a daily basis. (Subramanian N, 2010)The hot and humid climate of Dubai means that there will be a significant amount of cooling that needs to be provided to keep the building conditions at a comfort level. During peak hours close to 10000 tonnes of cooling is required which will also therefore generate lot of moisture to get condensed from the air. Approximately 57 million litres of water is collected as a by product of cooling and condensation. (Subramanian N, 2010) The electrical load required during peak hours is 50 MVA. The first 37 floors of this tower are occupied by Giorgio Armani Hotel. The total cost of the project is estimated at 20 billion US dollars. The cost of constructing the tower adds up to 4.2 billion US dollars. Cultural & Social and other considerations Dubai is an all welcoming society and traditionally there has been no bias against any community. People visit Dubai not just as a tourist destination but also an attractive area for getting employed. While the population of Dubai is quoted at 1,112,000, the national population of Arabs would be around 90,000. (DeNicola Christopher, 2005) Expatriate people therefore make a significant chunk of the population. Multinational companies have workers engaged in high end jobs who in turn are attracted by the free trade zones and tax incentives provided by the government. Dubai with is eye on tourism has prior to Burj Khalifa carried out several projects which has added to its repertoire of being a city that must be visited once in lifetime. The Burj Al Arab which is a seven star luxury hotel built in the shape of a huge snail and the Palm Island which is an artificial island created in the shape of Palm trees extending into the ocean are other noteworthy structures built to house numerous shopping malls and five star hotels. (DeNicola Christopher, 2005) The Dubai Shopping Festival also attracts a significant amount of tourists and the presence of Burj Khalifa is going to further add to this influx. The growth of Dubai over the last decade has been phenomenal since it was only forty years back that the primary source of income for the community was gold and fishing trade. (DeNicola Christopher, 2005) This has now paved way to real estate boom where tourism and an attractive shopping destination is what are drawing in crowds to Dubai. Several Multinational companies along with engineering firms have also set shop in Dubai because of the large scale of infrastructure projects that have commenced. In catering to the wishes and lifestyle of the westerners who flock to this destination the government has loosened all restrictions and has also gone as far as prohibiting the call for prayer from the Jumeirah Mosque on the basis of complaints by European nationals. (DeNicola Christopher, 2005) This has rubbed off the wrong way on the local populace and they see this kind of pandering to the West as being too submissive and extreme. However all said and done there was no significant opposition to the Burj Khalifa which at the moment is a symbol of great pride for the Arab population who feel that having the tallest building in the world located in Dubai is indeed an achievement. Politics and Public perception Politics and public perception also played a significant role in Sheikh Rashid Al Maktoum going ahead with the project as he had the backing of several of his aides, other equally important rulers and the general populace who saw pride in the piece that was being constructed. That the structure holds a special mention in the global scenario is a matter of extreme pride and efforts of the Sheikh in this achievement is being well appreciated. Philosophy & Religion Though the Burj Khalifa does not represent any religious monument of any sort, its mode of design represents some of the finer aspects of traditional Islamic architecture. There are many that argue as to the symbolism of this huge structure and the philosophy that went into its making. The only answer to that would be the ruler of Dubai in constructing this piece seeks to imprint Dubai into the global context. The height of the structure emphasizes that Dubai with it Burj Khalifa, towers above all its contemporaries and seeks to look down on other structures of equal grandeur which need to necessarily be located in the Middle East. In constructing this structure Dubai sends out a clear signal of economic and technological strength to the rest of the world. Structural & Design Innovations One of the main concerns while constructing this structure was safety of this structure to withstand seismic and wind loads. Wind loads were quite critical since sandstorms are a common feature in the desert and the height to diameter ratio being of such a disproportionate amount, effective measures needed to be built into the design to take care of wind loads. Taking into account the direction of prevailing winds the structure during the initial design phase was rotated by 120 degrees to reduce the direct impact of wind forces and provide a more contoured smooth passage for the wind. (Lego Architecture, 2010) Architecturally most of the sections used have vertical elements as horizontal projecting elements would have the tendency of accumulating the dust from any sandstorm. Mostly the building uses a mix of polished stainless steel and glass structures to prevent dirt from accumulating. (Subramanian N, 2010) While it adds to the aesthetic value this design brings in value addition to the monumental structure. Source: The external facade of Burj Khalifa, Lego Architecture, 2010 To account for the extreme height of the building, a new structural system was devised known as the buttressed core. In this system of design there is central hexagonal core which is strengthened and reinforced by three buttresses that form the ‘Y’ shape of the structure. (Subramanian N, 2010) To each wing there exist a concrete corridor walls and columns which buttress the other wings via a link connecting it to the hexagonal shaped central core. The structural system is so designed that with each rise, the building sets itself back in a spiral pattern. There are a total of 26 helical levels. Loading is distributed by aligning the above columns with the below walls to allow for smooth transfer of load. With each tier the width of the tower changes. This prevents the wind from building up vortices as with each elevation the wind encounters a different building pattern. (Novak C Lawrence, 2010) This system of design creates a robust structure that is well supported laterally and is not susceptible to twisting. To the top of the building is a spire made up of 4000 tonnes of steel and this acts as the central sculpted cone of this building providing the finishing touch to the Burj Khalifa. Wind Design The Burj Khalifa among various other factors was specifically designed to take extreme wind loads. Conditions of similar nature were simulated on prototypes to get loading conditions. The 3 dimensional models was generated using ETABS, a software created by Computers & Structures Inc of USA and details such as RC walls, slabs, piles and link beams were modelled and the corresponding wind and seismic loads applied. (Subramanian N, 2010) Creep and Shrinkage were also accounted in this design. For effective element analysis the 3D model had over 73500 shell elements with 75000 nodes. Link beams with a width of 650mm and height of 825mm were modelled and strut-and-tie method was used in these calculations.( Subramanian N, 2010) Wind tests were conducted on prototypes of the model at Guelph, Ontario, Canada prior to finalizing the design. Close to 40 wind tunnel tests were conducted which resulted in designers adopting the upward spiral receding shape thereby reducing vortex formation. (Subramanian N, 2010) Care was also taken in checking that each stage of the construction the structure along with the cranes was safe. Results of the dynamic analysis show that at the highest point, the building could sway within a safe limit of 1.5m. Source: Wind Tunnel model at Guelph, Ontario Canada, Subramanian N, 2010 Civil Foundation Details Samsung Engineering & Construction who had wide experience both in the Taipei 101 tower and Petronas Twin Tower was entrusted with the task of construction. Raft foundation of thickness 3.7m was used which in turn was supported by reinforced concrete piles. C50 grade self-consolidating concrete (SCC) was used and the volume of concrete used amounted to 12500 m^3. (Subramanian N, 2010) A total of 194 numbers, 1.5 m diameter and 43m long cast-in place piles were used with the bearing capacity of each pile close to 3000 tonnes. Source: Piled raft foundation, Subramanian N, 2010 The Treamie method using polymer slurry was used in creating this high density and low permeability pile using C60 grade SCC concrete. Sufficient cathodic protection was also installed in the foundation to account for corrosive action of ground water which has a tendency of forming electrochemical cells. The C60 High Performance concrete uses Portland cement and fly ash as its keys ingredients and possesses a Youngs Modulus of 43,800 mPa. (Subramanian N, 2010) Two large concrete pumps were used in transferring the concrete mix to heights over 600m. To reduce cracks that might crop up during shrinkage, the concrete was mixed at night when temperatures in Dubai are at its lowest and the humidity is higher. Ice was also added while mixing the concrete. Cranes and Tower Cladding Three numbers of Favco tower cranes were used alongside the central core and are capable of lifting loads up to 25 tonnes. The exterior surface of Burj Khalifa is made of reflective aluminium and stainless steel spandrel panels having tubular fins. A total of 28261 panels have been used and temperatures ascertained show that the top of the tower is 6 degrees cooler than the base. (Subramanian N, 2010) The advantage of this design is that it possesses strong resistance to heat and solar rays. There are 18 permanent track and fixed telescopic building maintenance units who are responsible cleaning of the outer facade of the Burj Khalifa building. If cleaning is carried from top to the bottom accessibility is available till the seventh floor. However it has been estimated that a total of four months would be required to clean the entire outer facade of the structure. Other Highlights The walls were constructed using Doka’s SKE 100 automatic self-climbing formwork. Construction hoists of capacity 3200 kg at speeds of 120 m/minute were used in movement of material and manpower to stipulated heights. To maintain plumbness of the structure with each ascending spire, a GPS system was put in place to check for verticality. Walkie-Talkies with ROIP and VOIP features were used for communication over vertical distances of 30 floors. (Subramanian N, 2010) All sub-contractors were taken into confidence during each stage of the construction project. Graphical 3D models updated at the end of each stage were shared to let these workers feel more involved in the work. The interior design of Burj Khalifa was done by Nada Adric of SOM. Some of the features include the use of glass, stainless steel, polished stones which had silver travertine floors. Rugs made by hand with Venetian stucco walls and approximately 1000 pieces of art and painting were also an important facet of this structure. (Subramanian N, 2010) To bring about an effective ambience a 275 m long fountain has been installed at the front of the tower at an approximate cost of 220 million US dollars. Approximately 22000 gallons of water is sprayed to a height of 150 m. (Subramanian N, 2010) These water fountains are coloured using a mix of 6000 electric bulbs and 50 coloured projectors Conclusion There have been various interpretations as to the significance and importance of the Burj Khalifa in the context of Dubai and its scheme of things. One school of thought feels that this structure represents opulence and extravagance. With the amount of electricity and other water resources that the building consumes in carrying out its daily routine activities, the Burj Khalifa is adding to the burden of the region when seen in the global context. Many feel that this structure was built just to satisfy the personal ego of the ruler of Dubai and to achieve the distinction of having overtaken the height of the Petronas twin tower which was till that point in time being considered as the tallest tower in the world. The other school of thought would like to view this structure not in terms of the money involved, the energy it consumes or the increase in carbon footprint in constructing this piece but purely in terms of being a structural and architectural masterpiece. To construct a 828 metre high vertical tower in the heart of Dubai and in an area where wind loads are extremely high required detailed engineering of the highest kind. Further the shape of the structure which was not just aesthetically pleasing but also contributed to the accumulation of dirt or sand on the external facade was an innovation. The sheer size of this structure which was also built in record four years speaks of the meticulous planning that went into the design and construction of the Burj Khalifa. Purely viewed in the context of architecture, the Burj Khalifa holds a special significance among all pieces of modern structural buildings built in the 21st century. Reference List Lego Architecture, 2010, Burj Khalifa, Retrieved from http:// cache.lego.com/bigdownloads/buildinginstructions/4647837.pdf DeNicola Christopher, 2005, Dubais Political and Economic Development: An Oasis in the Desert, Retrieved from http:// www. library.williams.edu/theses/pdf.php?id=48 Novak C Lawrence, 2010, Challenges and Innovation in Civil & Environmental Engineering, Spring 2010 Seminar Series, Retrieved from http:// www. nd.edu/~jjwteach/2010_spring_flyers/Flyer_Novak_20100407.pdf Subramanian N, 2010, Burj Khalifa-World’s Tallest Structure, NBM & CW, Vol 15, Retrieved from http:// www.sefindia.org/q=system/files/BURJ+KHALIFA...Building.pdf Read More