George Keleris has been a member of the Institution for 20 years. Here he discusses his work on Queen Alia International Airport in Jordan, which has been shortlisted for The Structural Awards 2017.
Queen Alia Airport is located approximately 30km South of Amman, capital of the Kingdom of Jordan, and was conceived in 2005 through a collaboration between Foster + Partners and BuroHappold Engineering.
The architectural concept involved a striking roof structure, under which the entire airport building could operate. The airport is orientated approximately east-west, and consists of three major buildings arranged symmetrically along a longitudinal axis, reflecting passenger flow.
When you approach the design of an airport this consideration of the way passengers will move through the building is crucial, as is the provision of a comfortable, pleasant and secure environment. It was also important, as the gateway into Jordan, that the airport made the right first impression on visitors, respecting and relating to its environment. These considerations governed the design throughout.
The structure is highly complex, but the roof was perhaps the dominant challenge: it’s the main feature that reflects Jordanian culture: the repeated dome roof shape, viewed from above, recalls traditional Bedouin tents, while the various concrete shapes draw upon the shape of desert palms when viewed from below.
Foster + Partners wanted to limit the number of internal columns supporting the roof, in order to provide as much clear space as possible in a modular arrangement: typically, a structure like this would have column supports on an 8m - 9m grid but we needed to develop a structural system that was able to span up to 25m between columns. This challenge saw us develop a theory around concrete domes that would “arch” between the infrequent columns. The vaulted roof shells are either square or triangular on plan, and consist of composite RC/precast shutter domes bound by arching ‘X-beams’ along their perimeters.
The design also sought to create a comfortable environment that was as efficient as possible. The roof – a key part of the building’s sustainable strategy – integrates architecture and engineering, and is made of “massive” concrete elements, which absorb much of the summer through its inherent thermal mass, insulating passengers from the harsh environment and minimising the need for (active) mechanical cooling systems.
Together with Foster + Partners we developed a construction system that followed a “kit of parts” approach, effectively simplifying the system into a giant Lego set, where the individual components are easily connected on site. Construction costs are now very much governed by the time it takes to build things, so a system like this speeds things up immensely.
The greatest achievement for us as engineers is how we have met the architect’s objective entirely through the expression of the structural system. The form and finish are all “naked” and for all to see and it looks beautiful.
Once constructed, it was evident to the client that they had something special. The entire design team was represented at the opening ceremony with the King of Jordan and we all could see his delight. We look forward to the Structural Awards ceremony on 17 November and viewing the other great engineering projects on show.
Image by J&P (Overseas) Ltd - all others by Foster + Partners.
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