ICE London Civil Engineering Awards 2013

Al Bahar Towers

Architect & Lead Consultant: Aedas Architects Ltd
Client: Abu Dhabi Investment Council
Engineer: Arup
Cost Consultant: Davis Langdon
Landscape Architect: Townshend Landscape Architects
Architect of Record and Contract Administrator: Diar Consult
Architect of Record and Contract Administrator: Al Futtaim Carillion LLC

Images 1 and 7 © Arup. Images 2,6,8 and 9 © Christian Richters. Images 3,4,5 and 10 © Aedas.

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The Abu Dhabi Investment Council headquarters, known as the Al Bahar Towers, feature an innovative dynamic façade which opens and closes in response to the movement of the sun, reducing solar gain by over 50%, creating a more comfortable internal environment for occupants and producing a distinctive external aesthetic which helps to define the building as a gateway to the city.

The dynamic façade has been conceived as a contemporary interpretation of the traditional Islamic ‘mashrabiya’; a popular form of wooden lattice screen found in vernacular Islamic architecture and used as a device for achieving privacy while reducing glare and solar gain.

The ‘mashrabiya’ at Al Bahr Towers comprises a series of transparent umbrella-like components that open and close in response to the sun’s path. Each of the two towers comprises over 1,000 individual shading devices that are controlled via the Building management System, creating an intelligent façade.



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Each IP addressable unit comprises a series of stretched PTFE panels and is driven by a linear actuator that progressively open and close once per day in response to a pre-programmed sequence that has been calculated to prevent direct sunlight from striking the façade and to limit direct solar gain to a maximum of 400 watts per linear metre. The entire installation is protected by a variety of sensors that will open the units in the event of overcast conditions or high winds.


This is the first time such a responsive façade has been used at this scale and in the Gulf region. The following are among the benefits to have been derived from such an approach:
 

Lighting and Views:
- Reduced glare
- Less heavily tinted glazing and improved daylight penetration
- Less frequent use of internal blinds
- Less reliance on artificial lighting
- Improved views for occupants of the building
 

Energy Consumption:
- Over 50% reduction in solar gain
- Significant reduction in electrical energy consumption
- Significant reduction in cooling loads
- Improved comfort levels for occupants
- Total site CO2 emissions reduction of over 1,750 tonnes per year



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Working closely with colleagues at Arup, the Aedas team also drew upon the skills of its in-house Research & Development group to apply advanced computational design techniques in support of the project. During the competition stage, the group developed bespoke applications to simulate the movement of the façade in response to the sun’s path as proof of concept and, following award, went on to support the detailed design development by undertaking a variety of additional simulations.

Drawing upon the principles of Islamic composition, the same advanced techniques were also used to generate the form of the towers from which a single integrated building model was created that was then used to ensure the proper coordination of the various building elements throughout the documentation and construction stages of the project.

The building incorporates the use of solar thermal panels for hot water heating and will be one of the first completed buildings in the Gulf to receive a LEED Silver rating. The building will be completed on budget, is scheduled for occupation in the first quarter of 2013, and has already been included in the Council for Tall Buildings & Urban Habitat’s (CTBUH) list of ‘Innovative 20’ tall buildings that ‘challenge the typology of tall buildings in the 21st Century’.



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