Although the desing constraints are rather severe ONL has found a strategy which features a combination of an iconic architecture and a functional lay-out. ONL has valuable experience with realizing nonstandard arcitecture for normal standard budgets. In ONL's design philosophy, architecture, construction and decoration are integrated in one consistent design attitude. The structural logic is expressed in the architecture, the decorative patterns of the facade are the detailed expression of the architectural tesselation of the surfaces. This integrated approach forms the basis for the marriage of cost-effectiveness and architectural eloquence.

ONL has decided to develop a vase shaped tower, narrow at its base, gaining volume in the shaft and tapered towards the top. Since plot C.08 is a plot with a medium sized tower [GF + 1 + 19 Floors] ONL ONL wishes to have a narrower top to allow for more open views from the higher buildings around. The vase has been styled by subtly slicing and chamfering the otherwise rectangular floorplan. Relatively modest interventions and parametric modifications of the rectangular basic shape while retaining the structural integrity of the design create the iconic appearance of the tower.

ONL's unique parametric design system forms the basis for the nonstandard approach and allows for the apparent variations in window shapes and sizes. The by ONL-MS Design & Build [ONL's engineering branch] developed software for the competitive file-to-factory production process guarantees the cost-effectiveness of their iconic designs.

Glass, contrast colour and LED light

The smooth façade is the architectural expression of the triangulated structural concept. The structure includes diagonal in every structural bay which makes the construction extremely rigid. Because of its structural logic and the high frequency of the tesselation the loadbearing facade structure [executed either in steel or prefabricated concrete] can be calculated to be slim, lightweight and hence cost-effective.

The cladding of the glass façade follows the frequency of the tesselation and is attached directly to the structural components. Therefore a secondary support structure is not needed to hold the components of the glass façade in place. Thus the budget for the façade can be used to its full extent for the visual appearance.

The material ONL has chosen for the façade is glass. Transparent vision glass for the window openings and non-vision spandrel enamel glass panels for the coloured surfaces inbetween the windows. The body colour for the glass spandrel panels is 'emalit contrast' in red copper. The colour appears to be slightly shifting when looking at it from a different angle, herewith bringing more life in the façade treatment. The windows are lit by a set of three programmable RGB LED light fixtures embedded in the day sides of the exterior walls. ONL imagines that each day of the week the glow of the window day sides is programmed to light up in another colour. On special occasions the light may be programmed to draw simple signs and images on the thus pixelated façade using the windows as the pixels.

Base shaft capital

The vase shaped volume makes every floorplan unique. The vase shape integrates base, shaft and capital into one coherent gesture. Each floor has a slightly modified outline, while retaining its full functionality of a vertical central core with elevators, stairs, shafts, electricity room, etisalat room and toilets, surrounded at all four sides by a corridor and the peripheral zone with offices. The central core is placed a-symmetrically as to allow for the positioning of internal meeting rooms, which do not require daylight. The proposed straightforward lay-out allows for direct daylight into all office spaces.

The basement contains all parking spaces. The podium offers a large retail space, perhaps open for negotiation with additional parking spaces, which appear to be slightly too economical in the actual lay-out. The feature entrance is developed as a generous specification of the parametric façade system, offering large openings with recessed fully glazed façade for the double height entrance lobby. The roof of the podium is developed as a stylish roof garden, preferably with a small pavilion and some art sculptures.

The top floor will be dedicated to fitness, clubbing and other leisure activities open for office personel. From there an inviting stair is leading up to a feature bar and from there to the roofgarden. The façade form the periphery of the roofgarden, glazed at balustrade level and with non-glazed openings at the contour of the topping. Strong light will shine from inside the roofgarden towards the exterior as to establish an atmospheric night feature of a the fairy-like arabesque.

Sustainability

The shape of the tower improves the sustainability in respect to wind loads since the corners of the floorplan, especially in the shaft and the capital part, are chamfered and rounded off.

The window openings count for 20-25% of the façade surface, at the same time reducing the cooling loss through the windows and reducing the amount of heat coming into the office floors. Silvery transparent coated glass takes care of a good ZTA / LTA value.

The façade is completely covered with glass, 20-25% vision glass 75-80% contrast coloured spandrel panels. The structural glazing technique guarantees minimal concentration of moist dust grains and sets the sound basis for low maintenance costs. Self-cleaning glass will be considered but has to be proofed for the harsh Emirates climate.

All office space are not deeper then 6m, making all workers profit from direct daylight, and hence saving on lighting costs. The offices are divided in two zones, one closer to the daylight using less artifical light. The zones can be switched on/off separately.

The fully ICT driven file to factory process alows for a maximum control on the produced materials. All components are mass-customized, which means that there will be no waste material whatsoever. Mass-customization offers high-level of sustainability as seen in relation to traditional mass-production methods

The load-bearing structural façade needs no separate support structure for the façade cladding system. The same tringulation / tesselation is used for the structural support system as for the cladding system. ONL's innovative structural façade system reduces working hours, time and hence money and is naturally sustainable due to its its common sense straightforwardness.

Size: 21.700 m2

Site: Capital Centre Development, Abu Dhabi

Design: ONL [Oosterhuis_Lénárd]

Lead designers: Kas Oosterhuis, Ilona Lénárd

Project architect: Gijs Joosen

Design Team: Marthijn Pool, Ronald Brandsma, Petr Vokal, Jan Gasparik, Tim McGinley