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Located in downtown Dubai Business Center, at 2717 feet high, the Burj Khalifa has been the world’s tallest skyscraper since 2010, rising above the now second tallest skyscraper, Taipei 101, by over 1000 feet in a period of six years. The vision that the main architect, Adrian Smith, had for the structure was to create a building that reflected the form of a Hymenocallis flower.This idea was translated into the final design using a y-shaped form for the structure. The Burj Khalifa may be viewed as a great work of architecture for its innovation in design and elegance but the execution of the design to aid in constructability and minimizing loads, its multi-purpose uses to the public, and its local and global importance make the structure a prime example of structural art.

Qualifications as Structural art




Scientific
The form of the Burj Khalifa succeeds in providing an efficient structural system illustrating attention to permanence and durability of the structure. The top section of the structure has a diagonally braced lateral system with a structural steel spire designed to resist “gravity, wind, seismic and fatigue”. The y-shaped form has three ‘wings’ aligned with a grid that are buttressed to a central hexagonal core made of reinforced concrete. This system provides the structure with lateral and torsional stiffness. High-performance concrete corridor walls extend from the central core and end with thick hammerhead walls which resist wind shear and moments. The wings contain these corridor walls and concrete perimeter columns which are also located on outriggers. Here, the columns are efficiently linked to the thicker interior walls so that they support gravitational dead loads which in turn maximize the system’s resistance to lateral loads. The design of the interior walls and perimeter columns reduce creep and shrinkage by ensuring that the stresses on both are equal by creating thicker walls and thinner columns proportional to the magnitude of the forces.

The extreme height and slenderness of the structure is a result of a spiral pattern around the y-shaped plan created by the stepping back of different tiers of the structure with the wings aligned with the columns. This also provides a smooth load path without structural column transfers. The different shapes and staggering of the building reduce wind loads by ‘confusing the wind’ provides resistance against torsional forces. The concrete base ensures stability against natural elements such as the wind, seismic activity, corrosive ground water, and its own gravity load. The Willis Tower (formerly known as the Sears Tower) has a similar design as the Burj Khalifa to resist wind loads with spiraling setbacks but its base is made up of square tubes and a steel frame that occupy three times the square footage as the Burj Khalifa and at nearly half the height. For comparison, the Willis tower weighs 222,500 tons, at 1,450 feet high, and has a concrete foundation of 2,000,000 cubic feet and the Burj Khalifa weighs 500,000 tons with reinforced concrete for foundation with a volume of 441,433 cubic feet. This illustrates the efficiency of Burj Khalifa’s design which occupies less horizontal space and significantly more vertical space.

Social
It’s debatable whether the Burj Khalifa is worth the $1.5 billion cost for construction compared to the $950,000 for constructing the Willis Tower in 1973. However, considering the accommodations for the public and the conscious effort made to minimize costs with alternative construction methods, the structure is an accomplishment economically. The structure dedicates 160 floors to a hotel, residential area, offices, and a public observatory to name a few spaces. To ensure the safety of inhabitants, the structure is equipped with fire proofed materials, concrete staircases, and emergency elevators. The chief structural engineer for the project, Bill Baker, created the buttressed core structural system for the Burj Khalifa to achieve the record-breaking height without great costs. The setbacks, or extensions, of the y-shaped form aided in constructability because the extensions were built off of the central part of the structure (see images “Cross-section Comparisons” and “Different Tiers of Burj Khalifa”). The exterior consists of glass and cladding with reflective glazing of aluminum and textured stainless steel panels designed to withstand extreme seasonal heat and wind. The use of aluminum illustrates the importance of efficiency because the material is light, durable, and economical. Also, the joints of exterior glass panels are angled to disperse sunlight and the wind as an effective alternative to expensive curved glass.

Symbolic
During pre-construction, specific objectives had been made for the Burj Khalifa but after construction, the structure’s presence developed local and global meaning, making it an exemplary work of structural art. Initially, the plan for the construction of the Burj Khalifa was made to prove the United Arab Emirates’ capability and innovation as developing countries to the rest of the world. The government’s decision to build the structure in the business center of Dubai was centered around the idea of creating an economy based on tourism and international recognition. Since the completion of the Burj Khalifa, the structure is valued as a success in international collaboration, with specialists from China for the exterior cladding work, architects and engineers from S.O.M. in the US, and a variety of services from within the U.A.E. and it is also seen as an inspiration for the surrounding developing countries. The completed structure illustrates modernism mixed with cross-cultural aesthetic values within and beyond Islamic architectural and the form of onion domes. Smith comments on its local impact saying that the Burj Khalifa is a “harbinger of the future” as “developing countries follow [the Burj Dubai’s] prototype of the mega-scale, master-planned community” and prepare to “join the supertall race”.