Shape of things to come - New HQ takes the form of a sphere in the desert

When a leading Abu Dhabi property developer held an international design competition to choose the architect for its new headquarters, it specified a 40-storey office tower. The firm never dreamed the floor area would be provided by an alternative design that puts a whole new spin on the traditional office high-rise.

Local architectural firm MZ Architects won the competition with a design by architect and general manager Marwan Zgheib. This presented a semi-spherical building comprising two bivalve-like facades linked by a narrow band of indented glazing, with the entire volume defined by solid circular bands of steel. To enhance the dynamic curved form, the glazed area between the two shells narrows towards the centre, creating a gap of approximately 1.8m. The glazing widens at the top and bottom to 8m.

Managing partner Tony Abi Gebrayel says the concept of a spherical building was originally mooted in the 1920s, as an ideology of pure geometry. But it is only in recent years that the computer software has become available to engineer such a building.

"It is in fact an extremely stable geometry, with steep V columns and two cores anchoring the base. The double core was required to mitigate the effect of the increased surface area exposed to the wind."

Abi Gebrayel says the structure is based on a triangular diagrid, which allows greater flexibility than a conventional rectangular form.

"The diagrid is an essential part of the structural design, as it supports the slabs to ensure a column-free space. This improves the building's efficiency, providing layout flexibility for tenants. Although there are just 23 floors, the building has the same floor area as a typical 40-storey tower. And because each panel on the diagrid has three sides, rather than four, it was easier to accommodate the curved shape of the curtain wall."

Large diamond-shaped mullions on the curtain wall reinforce the sense of scale there are four storeys between each node of the diamond.

Abi Gebrayel says that the narrower base of the building makes it less suitable for traditional, street-front retail premises. But it makes it ideally suited to corporate headquarters, which don't require large ground-floor areas. The variation in the size of the floorplates on each level from 200m² to 2500m² also provides diversity for tenants with different space requirements.

The entry to the building leads to a soaring, double-height atrium, with marble floors and stone-clad walls finished in a diamond grid pattern that mimics the exterior of the building. Shared informal meeting spaces on the ground level ensure this is not purely a circulation space.

Designed to meet LEED certification criteria, the building maximises natural light, with meeting areas and offices spread around the perimeter of each floor. Abi Gebrayel says the building's efficiency is classed as 82%, making it the most efficient design for the floor area.

Aldar Properties occupies two floors and the remaining floors are tenanted.

"The building has succeeded in raising the profile of the company, which is developing many new properties in the burgeoning Al Raha Beach city," says Abi Gebrayel. "From a distance, the building looks like a giant sculpture or a monument. It can even be seen from the Formula One racetrack.

"The reflective nature of the facade is a key drawcard. The bottom half reflects the landscape, while the top reflects the sky. There is a clear horizon across the middle, and at certain times of the day, the orb of the sphere is perfectly matched by the orb of the sun."

Story by: Colleen Hawkes