BURJ KHALIFA: TECHNICAL REVIEW AND SPECIFICATIONS

The Burj Khalifa serves as the global benchmark for supertall construction and remains the tallest building in the world. Rising 828 meters (2,717 feet) above Downtown Dubai, this megastructure represents a paradigm shift in high-rise engineering, moving beyond the traditional tubular steel frames of the 20th century to a high-performance reinforced concrete buttressed core system.

This technical review analyzes the structural innovations, the aerodynamic shaping strategy, and the advanced building systems that allow the Burj Khalifa to function efficiently in an extreme desert climate.

ARCHITECTURAL DESIGN AND THE BUTTRESSED CORE

Designed by Adrian Smith at Skidmore, Owings & Merrill (SOM), the Burj Khalifa's form is derived from the Hymenocallis flower (Spider Lily) and Islamic geometries. The tower features a tripod-shaped footprint with three wings extending from a central core. This Y-shaped floor plan provides the maximum amount of perimeter for windows, offering unobstructed views of the Arabian Gulf and the city.

From a structural perspective, this Y-shape forms the "buttressed core." Each of the three wings buttresses the others via a six-sided central core, providing exceptional torsional resistance. As the building rises, the wings set back in a spiraling pattern. These setbacks are not merely aesthetic; they reduce the cross-section of the tower as it ascends, decreasing the wind forces applied to the structure.

WIND ENGINEERING AND VORTEX SHEDDING

The primary challenge for a building of this height is not gravity, but wind. To mitigate the effects of vortex shedding—where wind creates alternating low-pressure zones that cause lateral oscillation—the tower's setbacks are arranged in a helical pattern.

By changing the width and shape of the building at each tier, the design confuses the wind. The wind vortices never have a chance to organize into a coherent pattern that would amplify the building's sway. Extensive wind tunnel testing confirmed that this geometry allows the tower to perform exceptionally well, even during severe Shamal sandstorms.

FOUNDATION AND GEOTECHNICAL SYSTEMS

The Burj Khalifa sits on a massive podium supported by a pile-raft foundation. The superstructure is supported by 192 bored reinforced concrete piles, each 1.5 meters in diameter and 43 meters long. These piles are driven deep into the soft rock and rely on skin friction to support the 500,000-tonne weight of the building.

To combat the highly corrosive, saline groundwater of the Dubai coast, the foundation system utilizes a specialized cathodic protection system. This electrical system prevents the steel reinforcement within the concrete piles from rusting, ensuring the structural longevity of the foundation.

VERTICAL TRANSPORTATION

The vertical transportation system, supplied by Otis, is one of the most complex ever devised. The tower houses 57 elevators and 8 escalators. The service elevator acts as the world's highest service lift, traveling the full height of the central core.

The building utilizes double-deck elevators for the observation deck (At the Top), traveling at speeds of 10 meters per second. To manage the "stack effect" (the movement of air due to pressure and temperature differences), the elevator shafts are pressurized and equipped with airlocks to prevent the whistling noise and door jams common in supertalls.

FACADE AND CLADDING SYSTEM

The exterior cladding consists of reflective glazing with aluminum and textured stainless steel spandrel panels. The system is designed to withstand extreme summer temperatures, high wind pressures, and airborne sand.

The glass is coated with a high-performance Low-E (low emissivity) silver coating that reflects a significant portion of the intense solar radiation. The facade covers an area of approximately 132,000 square meters—equivalent to 17 soccer fields. The cleaning system involves permanent track-mounted telescopic cradles stored in mechanical garages at three different levels of the tower.

MECHANICAL SYSTEMS AND CONDENSATE RECOVERY

In the hot and humid climate of Dubai, the air conditioning system produces a significant amount of condensation. The Burj Khalifa employs a condensate recovery system that collects this moisture from the cooling units.

This recovered water is piped to a holding tank in the basement car park. The system collects approximately 15 million gallons of water annually, which is then used for the irrigation of the landscaping and the Dubai Fountain lake, significantly reducing the potable water demand.

TECHNICAL DATA SHEET

Official Name: Burj Khalifa
Location: 1 Sheikh Mohammed bin Rashid Blvd, Dubai, UAE
Architect: Skidmore, Owings & Merrill (SOM)
Structural Engineer: Bill Baker (SOM)
Main Contractor: Samsung C&T, Besix, Arabtec
Completion Year: 2010
Architectural Height: 828 meters (2,717 feet)
Floor Count: 163
Structural Material: Reinforced Concrete and Steel Spire
Elevator Supplier: Otis
Primary Function: Mixed-Use (Corporate Suites, Residential, Hotel Armani)

FREQUENTLY ASKED QUESTIONS

Does the Burj Khalifa sway?
Yes, all supertall buildings sway to dissipate wind energy. At the top, the Burj Khalifa can sway by about 1.5 to 2 meters during extreme weather, but the movement is slow and generally imperceptible to occupants due to the high mass of the concrete structure.

What is the tip of the building made of?
The top 200 meters of the tower is a steel spire structure. Unlike the lower reinforced concrete sections, the spire is a steel pipe frame. It houses telecommunications equipment and completes the architectural height.

Is the foundation sitting on bedrock?
No. The ground in Dubai consists of sandstone and siltstone. The piles rely on friction against this soil (skin friction) rather than resting on a solid bedrock layer.

How long does it take to clean the windows?
Under normal conditions, it takes a team of 36 cleaners approximately three to four months to clean the entire exterior facade once.