Burj Khalifa Case Study: Buttressed Core, Wind and Foundation (SOM)

Burj Khalifa in Dubai is an 828 m mixed-use tower designed by Skidmore, Owings & Merrill (SOM) for Emaar Properties, started in 2004 and opened on 4 January 2010. For a case study it teaches three linked ideas: a Y-shaped "buttressed core" in which three wings brace a central hexagonal core, setbacks that spiral up the tower and were reshaped in the wind tunnel so that the wind never meets the same shape for long, and a piled raft on weak, carbonate rock.

Burj Khalifa at a glance

Design architect and structural engineer: Skidmore, Owings & Merrill (SOM), Chicago. Adrian Smith was consulting design partner, George Efstathiou partner in charge and William F. Baker the structural engineer (Architectural Record, 2010).
Architect and engineer of record: Hyder Consulting, which also designed the foundations, with Harry Poulos of Coffey as independent geotechnical reviewer.
Wind: RWDI, among others. Builder: a joint venture of Samsung C&T, BESIX and Arabtec. Client: Emaar Properties.
Location: Downtown Dubai, United Arab Emirates; site 104,210 m² (SOM).
Dates: design competition 2002 (Architectural Record) or early 2003 (SOM's engineers); construction from 2004; design finished 2006 (SOM); opened 4 January 2010.
Height: 828 m (2,717 ft) to the architectural top; 829.8 m to the tip; highest occupied floor 584.5 m (CTBUH Skyscraper Center).
Floors: 163 above ground and 1 below (Skyscraper Center); SOM's page gives 160 and 162.
Area: tower gross floor area 309,473 m² (Skyscraper Center); SOM gives 454,249 m² building gross area.
Status: hotel, homes, offices and observation decks; open to visitors.

Sources are listed at the end. Diagrams are MOA's own schematics, not copies of the architects' drawings; UAE law has no usable freedom of panorama for buildings, so we use no photographs.

The brief and the client

Emaar wanted the centrepiece of a new district, with homes, a hotel and offices in one tower. Ahmad Abdelrazaq, who worked on the structure at SOM and later for Samsung, says the original concept was mostly residential, which favoured concrete and narrow wings with views and daylight (Abdelrazaq, SMAR 2011).

SOM's engineers William F. Baker and James J. Pawlikowski write that SOM was approached in early 2003, followed by a short idea competition among invited teams (Civil Engineering, ASCE, October 2012). Blair Kamin, in Architectural Record, dates that competition to 2002. The final height was kept secret and confirmed as 828 m only at the opening (KHL, 5 January 2010). The tower was called Burj Dubai until that night, when it was renamed Burj Khalifa in honour of Sheikh Khalifa bin Zayed Al Nahyan, the UAE's president.

Site and context

The tower stands in Downtown Dubai, a 500-acre master-planned district in Kamin's account, with low-rise annexes at its base. Two site conditions drove the engineering. Wind: Baker and Pawlikowski give Dubai's most frequent strong winds as northwest, south and east. Ground: the geotechnical paper by Poulos and Bunce describes deep deposits of carbonate soils and rocks (ICCHGE 2008), and Tensar's summary of the design records weak marine silty sands over weak and very weak sandstone, siltstone and conglomerate (Tensar, 2020). To set out a site study of your own, see our guide to documenting a building for a case study.

Concept: a desert flower, a tripod and a spiral

SOM's project page says the design is inspired by the geometry of a regional desert flower and by the patterning systems of Islamic architecture. Baker and Pawlikowski trace the structure to SOM's Tower Palace III in Seoul (2004), a Y-shaped residential tower that behaved so well in the wind tunnel that its engineers saw the system could go much higher.

The massing follows from that tripod. Abdelrazaq describes three wings of four bays each around a central core, with one outer bay peeling away at every seventh floor as the tower spirals up. Asked about the height, Adrian Smith told Kamin, "I just wanted the proportions to be right."

Burj Khalifa floor plan and zoning

A typical floor is a Y: three wings at 120 degrees to each other around a six-sided central core. In Baker and Pawlikowski's account, the core holds all the lifts and vertical services, while each wing has its own egress stairs. Every wing is planned on a 9 m module. Corridor walls run down the centre of each wing, flats or hotel rooms sit either side, and the wings end in columns at the tip.

Early wing walls split living rooms from kitchens and baths, which put many doors through structure and made Dubai's rule on daylight in kitchens hard to meet. Once studies in autumn 2003 showed the central core alone could resist twisting, the main walls were moved to line the corridors (Baker and Pawlikowski). The floors themselves are 200 to 300 mm two-way flat plates spanning about 9 m from the core walls to the perimeter columns (Abdelrazaq).

The Armani hotel takes the lower 38 floors (Doka), with homes, offices and observation decks above. Unit counts differ: SOM lists 577 homes and 304 hotel keys; KHL (2010) gives 1,044 apartments and 49 office floors.

Schematic plan of a typical Burj Khalifa floor: three wings at 120 degrees around a grey six-sided core holding the lifts. Each wing has two red corridor spine walls ending in a short hammerhead wall, an egress stair, black perimeter columns along its sides and a red nose column at its tip. The outer bay of the top wing is shaded and dashed to show it is removed at the next setback. A notes panel lists published facts: wings of four bays on a 9 m module, the core resisting twisting while the wings resist shear and overturning, gravity load steered to hammerhead walls and nose columns, 200 to 300 mm flat plate floors spanning about 9 m, core walls from 1,300 to 500 mm, and one outer bay stepping back at every seventh floor — Three wings brace a six-sided core; walls at the corridor ends and columns at the wing tips add much of its resistance to overturning. Diagram: MOA

Structure: the buttressed core

Baker and Pawlikowski define it as a tripod: a strong central core anchors three wings, each buttressed by the other two. The core resists torsion; the wings add shear resistance and depth against overturning. SOM's page calls the result "extremely stiff torsionally". Baker, interviewed in 2025, compared it to a Gothic cathedral, where buttresses brace the walls (Khaleej Times).

Three rules made it buildable:

Manage gravity. The setbacks were arranged so that the nose of each tier sits on the cross-walls of the tier below. Gravity load is pushed out to the corridor-end walls and the nose columns, where it does the most good against wind. Abdelrazaq notes that most of the overturning resistance comes from the tower's own weight.
No transfers. A strict 9 m module and no transfer structures: columns stand over walls all the way down. SOM says this let construction proceed without the delays that column transfers cause.
Engage the perimeter. At the mechanical floors, outriggers (four-storey shear wall panels) tie the perimeter columns to the core. They redistribute loads up the height and control differential shortening, so most base columns are only slightly thicker than those at the top (Baker and Pawlikowski).

Core walls range from 1,300 mm to 500 mm thick, linked at every floor by 800 to 1,100 mm deep link beams. Concrete runs to level 156; above that, a braced steel frame carries the spire to about 750 m, and a steel pinnacle pipe runs from 2,100 mm diameter at its base to 1,200 mm at the top (Abdelrazaq).

Wind: "confusing the wind" with the setbacks

When SOM first tested the tower in the wind tunnel, Baker and Pawlikowski write, it showed large movements and base moments, and the cause was the shape and orientation rather than the structure. Over several rounds of tests the team changed the number and spacing of the setbacks and the shape of the wings. They also found that wind striking the pointed nose of a wing excited the tower less than wind striking the hollow between two wings, and chose the tower's orientation against Dubai's most frequent strong winds with that in mind.

Because the width changes at every setback, SOM says, the wind meets a different shape at each tier and its vortices cannot organise. The Khaleej Times reports that the tower was first designed at 518 m, and Baker says the wind refinement "allowed us to grow by 310 metres". Sources differ on direction: Baker and Pawlikowski say the final setbacks run clockwise, reversing an earlier scheme; Kamin describes a counterclockwise spiral.

Schematic elevation of Burj Khalifa: a stepped concrete tower narrowing in tiers, with a dashed central core, red bands marking mechanical floors with outriggers, and a red braced steel spire on top. Wind vortex spirals of different sizes sit beside the tiers with a note that each tier is a different width so vortices cannot line up. Labels give 828 m to the architectural top (2,717 ft) and 829.8 m to the tip, about 750 m for the top of the braced steel frame with the pinnacle pipe narrowing from 2,100 to 1,200 mm diameter, level 156 where concrete ends, 584.5 m for the highest occupied floor, 452 m at level 126 with C80 walls below and C60 above, and 95 m at level 26 with C80 podium and walls below. A notes panel adds C50 floor slabs, concrete pumped to a record 606 m in April 2008, and setbacks spiralling from wing to wing at every seventh floor — The tower narrows in tiers so the wind meets a different shape at each one; concrete grades step down with height and a steel spire finishes it. Diagram: MOA

Burj Khalifa foundation and foundation depth

The tower sits on a 3.7 m thick raft of self-compacting reinforced concrete, its base at -7.55 m on the Dubai Municipality datum (Abdelrazaq). Under it are 1.5 m diameter bored piles. Abdelrazaq says they reach about 45 m below the raft, founded at -55 m, for an assumed capacity of 3,000 tonnes each; Tensar's summary gives 192 piles 47.5 m long under the tower, and 734 piles 30 m long under the podium. A 2025 Khaleej Times article gives 194 piles, so the count differs by source.

Because the rock is weak and carbonate, the design had to allow for the friction along the piles degrading under repeated wind loading (Poulos and Bunce). Tensar reports an estimated settlement of 45 to 65 mm; the Khaleej Times says the tower settled about 50 mm. Sixteen survey points on top of the raft tracked it during construction, and Abdelrazaq reports that measured and predicted settlements agreed well. For difficult ground at house scale in India, see our guide to building on black cotton soil.

Schematic foundation section of Burj Khalifa: a grey 3.7 m thick raft just below ground, its base at -7.55 m on the Dubai Municipality datum, standing on a row of long pink bored piles that reach about -55 m, through weak marine silty sands into weak and very weak sandstone, siltstone and conglomerate. Small red arrows along the outer piles show skin friction. A notes panel lists published facts: piles 1.5 m in diameter, 192 under the tower according to Tensar or 194 according to a 2025 Khaleej Times report, assumed capacity 3,000 tonnes per pile, test piles loaded to 64 MN, estimated settlement 45 to 65 mm with about 50 mm reported, and 734 piles 30 m long under the podium — A thick raft spreads the tower's load onto long bored piles that grip weak rock along their length. Diagram: MOA

Materials and construction

Abdelrazaq says concrete was chosen for its mass, stiffness, pumpability, local availability and suitability for homes. A March 2008 report on the pumping gives the mixes: C80 with 20 mm aggregate for the podium and walls up to level 26 (95 m), C80 with 14 mm aggregate for walls up to level 126 (452 m), C60 above that, and C50 for all floor slabs (KHL, 19 March 2008). For grades on Indian sites, see our post on cement types and grades.

Concrete went up by pump. Putzmeister says its pumps reached 606 m vertically in April 2008 and placed about 165,000 m³ of high-strength concrete over 32 months (Pumps & Systems, 2015). Because of the heat, pours were done at night, the concrete was chilled at the plant with some mixing water replaced by ice, and it was held at 28°C on its way to site.

Walls were cast in 3.7 m lifts in Doka's self-climbing formwork, at a three-day cycle (Doka).

Light, climate and services

Baker told the Khaleej Times that only one-sixth of the building is in the sun at any time, and that its condensate recovery collects the equivalent of 20 Olympic pools of water a year. SOM describes "sky-sourced" ventilation that draws cooler, drier air from the top, and "life boat" lifts for evacuation. Kamin describes the skin as a glass and aluminium curtain wall with stainless steel fins. The Skyscraper Center lists 58 lift cars with a top speed of 10 m/s.

Reception: praise, doubts and the record

Kamin's 2010 review called the tower "gargantuan yet persuasive", architecture and not only a record. He also reported the doubts: a German planner called it a vanity project, Kamin said it was no paragon of sustainability, and many flats and offices stood empty after Dubai's 2009 property crash. The opening slipped from the original end-2008 target because of labour disputes, supplier problems and interior finishes (KHL, 2010).

On the structure, Abdelrazaq's monitoring of settlement, shortening, sway and two remote earthquakes (2008 and 2010) found measured and predicted behaviour in close agreement.

Burj Khalifa cost, in dollars and in rupees

Emaar put the cost of the tower at US$1.5 billion when it opened in January 2010 (Al Jazeera, 4 January 2010). At the January 2010 average rate of ₹45.8944 to the US dollar, from the US Federal Reserve's G.5 release, that is about ₹6,884 crore. This conversion does not account for inflation and is not a "cost to build today". Doka's page lists an unexplained "development cost" of US$20 billion; do not quote it as the tower's cost.

What designers in India can take from it

Our reading, not claims from the sources:

Shape the building for wind before sizing the structure. The Burj grew taller because its form changed in the wind tunnel, not because members got bigger. On a tall tower in Mumbai or another coastal city, get wind advice while the massing is still soft.
Agree one grid for parking and homes. Many Indian residential towers stack flats over parking, where columns that do not line up end in heavy transfer slabs. Settling one module early, as SOM did with 9 m, avoids them.
Treat hot-weather concreting as design. Night pours and chilled mixes were standard on the Burj. In an Indian summer, how high-grade concrete is placed belongs in the specification, not only on site.
Measure what you predicted. Survey points on the raft and strain gauges let the Burj team check the building against the model. A mid-rise on doubtful ground can have a few settlement points read through construction.

If you are choosing a tall-building thesis, our B.Arch thesis topics by typology lists mixed-use and high-rise briefs where these questions come up. Our 30 St Mary Axe case study is a useful contrast: a steel diagrid at the edge, not a concrete core at the centre.

Visiting Burj Khalifa

The tower is open to visitors through its observation decks. Doka gives 456 m for At the Top and 555 m for At the Top, SKY; the Skyscraper Center lists the observatory at 555.7 m. Check times and bookings on the official Burj Khalifa site. For the real drawings, see SOM's project page and the engineers' papers listed below.

Looking for an architect who thinks about structure and climate from the first sketch? Find an architect on MOA.

FAQ

Who designed Burj Khalifa?

Skidmore, Owings & Merrill (SOM) of Chicago, with Adrian Smith as consulting design partner and William F. Baker as structural engineer. Hyder Consulting was architect and engineer of record, and Emaar Properties was the client.

When was Burj Khalifa built and how long did it take?

Construction began in 2004 and the tower opened on 4 January 2010, about six years later. The original target was the end of 2008.

How tall is Burj Khalifa in metres and feet, and how many floors does it have?

828 m (2,717 ft) to the architectural top and 829.8 m to the tip, with the highest occupied floor at 584.5 m (CTBUH). Floor counts differ: the Skyscraper Center gives 163 above ground, SOM gives 160 and 162.

How deep is the Burj Khalifa foundation?

A 3.7 m raft sits on 1.5 m diameter bored piles about 45 to 47.5 m long, founded around 55 m below the Dubai datum. Sources give 192 or 194 piles under the tower.

What was the Burj Khalifa construction cost in rupees?

Emaar gave US$1.5 billion in 2010. At the January 2010 average rate of ₹45.89 per dollar (US Federal Reserve), that is about ₹6,884 crore, not adjusted for inflation.

Sources

SOM: Burj Khalifa (accessed 4 Nov 2026)
CTBUH Skyscraper Center: Burj Khalifa (accessed 4 Nov 2026)
William F. Baker and James J. Pawlikowski, Civil Engineering (ASCE), vol. 82 no. 10, October 2012, pp. 58 to 65: Higher and Higher: The Evolution of the Buttressed Core (library record; accessed 4 Nov 2026)
Ahmad Abdelrazaq, SMAR 2011 conference: Validating the Structural Behavior and Response of Burj Khalifa (accessed 4 Nov 2026)
Harry G. Poulos and Grahame Bunce, 6th International Conference on Case Histories in Geotechnical Engineering, 2008: Foundation Design for the Burj Dubai, the World's Tallest Building (abstract; accessed 4 Nov 2026)
Andrew Lees, Tensar: A tall order, 13 August 2020 (accessed 4 Nov 2026)
Blair Kamin, Architectural Record: Burj Khalifa, 16 August 2010 (accessed 4 Nov 2026)
Somya Mehta, Khaleej Times: Burj Khalifa's structural mastermind reveals construction journey, 2 January 2025 (accessed 4 Nov 2026)
Steve Skinner, KHL: Burj Dubai opens with name change, 5 January 2010 (accessed 4 Nov 2026)
KHL: World record pump height, 19 March 2008 (accessed 4 Nov 2026)
Putzmeister, Pumps & Systems: Concrete pumps reach record-breaking heights at Burj Khalifa, 20 July 2015 (accessed 4 Nov 2026)
Doka: Burj Khalifa reference project (accessed 4 Nov 2026)
Al Jazeera: Dubai opens world's tallest tower, 4 January 2010 (accessed 4 Nov 2026)
US Federal Reserve: G.5 Foreign Exchange Rates, 1 February 2010 (accessed 4 Nov 2026)
Burj Khalifa: official site (accessed 4 Nov 2026)
Wikimedia Commons: Copyright rules by territory: United Arab Emirates (accessed 4 Nov 2026)