Building: Business Bay , Dubai, United Arab Emirates
Client: Albaraka Islamic Bank, Bahrain
Architect: Reiser + Umemoto RUR Architecture, PC
Structure Type: 22 Story / Concrete Structure
Ysrael A. Seinuk Area of Specialization:
2010 - ACEC National Honor Award for Excellence in Engineering Design
ACEC2010 - ACEC Diamond Award
ACEC2009 - CIB Award of Merit
Out of Country New York Concrete Industry Board
Among the iconic structures in Dubai, O-14 is truly unique. Its perforated concrete exterior shell is its main architectural feature and also its primary structural system. This exoskeleton-sunscreen wall features more than 1,300 openings of different sizes, arranged in an apparently random pattern. In fact, the seemingly arbitrary arrangement of the openings in the wall creates a diagonal grid that enables its use as a gravity and lateral supporting system.
A two-story podium encircles the 22-story tall commercial building. Structurally independent of the tower, the podium is supported by a 165-feet truss in the north, and nine circular columns in the interior. At the east and west property lines, it is supported by reinforced concrete walls. Five pedestrian bridges, each passing through a wall opening provide access between the tower and the podium.
The architect and structural engineer collaborated closely in configuring the entire facade. The sizes and locations of the openings were carefully coordinated in order to make the wall effective in channeling both gravity and lateral loads down to the base of the building. Several iterative analyses determined the final size and reinforcements of each solid shell element between the openings.
With four levels of parking below grade, a continuous 4-foot deep pick-up beam at the ground level transfers the vertical loads of the wall to 15 large garage columns. Meanwhile, the ground floor slab acts as a diaphragm, enabling the transfer of lateral forces to the foundation walls and core shear walls in the basements.
In plan, the exterior wall resembles a rectangle with curved corners and concave sides. Core walls surrounding the main office stairs and elevators, and the irregularly shaped exterior wall constitute the gravity and lateral supporting system of the building. The building is free of interior columns, with the floor slabs spanning between the interior core and the exterior shell.
The floor slabs connect to the exterior wall by crossing a 40-inch gap between the shell and main enclosure. This gap is a component of the "cooling system" for O-14, as it creates a space for hot air to rise, thereby cooling the surface of the glass windows behind the exterior shell. Because the openings vary throughout the facade, the slab connections are located at different points at each level.
The floor system of O-14 is a conventional flat plate system, with spans ranging from approximately 22 1/2 to 35 feet. Slab thicknesses are 8 inches and 12 inches in the typical office floors, with a 16-inch thick spandrel beam running along the perimeter of the floor slabs. In the underground parking levels, the floor slabs are 12 inches thick, with columns spaced at approximately 20 to 35 feet apart.
The entire structure is supported on drilled cast-in-place piles. With ground water 10 feet below grade level, the lowest basement floor, at approximately 51 feet below grade is a pressure slab with a minimum thickness of 40 inches. Lateral earth pressures at the basement levels are resisted by 30 two-inch thick diaphragm walls with tie-backs.