OR TAMBO

SPECIAL REPORT: OR TAMBO

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Images courtesy of ACSA.

A conceptual design challenge Central Terminal Building at the OR Tambo International Airport Innovative designs create an even balance between the built infrastructural requirements and ORT’s operational, technical and economic considerations.

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Since the Airports Company South Africa’s inception in 1993, Johannesburg’s international airport adjacent to Kempton Park has seen a growth rate that has become almost exponential, putting the airport’s infrastructure under pressure and making extra capacity and efficient movement of passengers a top priority. Now known at the OR Tambo International Airport, or ORT, this airport is now a world-class air transport hub, which hosts airlines from all five continents and forms part of a global network of trade, distribution and other economic activities.

According to the Airports Council’s international passenger statistics, ORT is busier than Brisbane and Dubai airports and its passenger traffic has even overtaken that of Cairo. The biggest and busiest airport on the continent, ORT is now capable of handling 25 million passengers annually.

Due to the dramatic increase in the airport’s passengers, ACSA has actively pursued the development of ORT not only as an airport of excellence and an entry point into the rest of Africa but also as an ‘aerocity’. To facilitate the achievement of its development objectives ACSA divided ORT into nine precincts dedicated to increasing and enhancing the efficiency and capacity of all its operations. Most of these precincts have undergone major infrastructural changes and development. The new Domestic Terminal building, which was completed in 2003, boosted ORT’s capacity to more than 16 million passengers a year. A R44 million domestic-to-international passenger transfer facility was opened in April 2004 and the International Terminal’s major upgrade is nearing completion.

Artist’s impressions of the CTB. Images by BAI.

and project director for the CTB development. “As a hub airport ORT has a focus to maximise the efficient processing of passengers and goods and therefore the conceptual design challenge for the CTB has been to find an even balance between the built infrastructural requirements and the operational, technical and economic considerations of ORT.”

Further developments include the Central Terminal Building (CTB), a new apron, the Gautrain link and several multi-storey car parks. Surrounding road infrastructure and access roads have also been upgraded.

“The design of a building within the space designated for the CTB is unique and challenging. A very significant part of the overall development at ORT, the CTB had to produce an efficient seamless structure which optimises capacity for the expected 25-million passengers.”

“The airport aims for the highest standards of service and its operations are run very tightly,” says Steve Riley, Bentel Associates International’s (BAI) architect

“There was substantial debate as regards the design and finishes of the CTB. However, practical decisions were made and a complimentary design approach was

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utilised. The structure features a spacious triple storey internal space, an enormous central atrium with a glass dome allowing plenty of natural lighting, lots of large and spacious open areas and overhead walkways to other buildings,” comments Riley. Décor, finishes and interior design echo the adjoining buildings providing continuity and enhancing the efficient flow of passengers and visitors. The exterior design of the CTB complements the other buildings creating an overall similarity in style.

“With this development we are ensuring that ORT can cater for all the people who will be moving in many directions through this hub. The enormous central atrium serves as a single entry point for all arriving and departing passengers as well as visitors to the airport. From this central core they will then move in different directions into the various parts of the building and further into connections with other parts of the airport, depending on where they want to be.

We have dealt with several challenging dynamics in this design. This is a highly complex environment and in addition, the whole precinct has had to remain fully operational during the CTB construction process.”

The CTB concept design also includes a huge retail component. Retail, one of ACSA’s three principal sources of revenue, is a key element in the company’s strategy to maximise non-aeronautical income. In addition, the airport station for a Gautrain link has been integrated with the CTB. ACSA has worked closely with the Gauteng Provincial Government on the development of the Gautrain high-speed link to ORT. The CTB comprises the following levels: › A double-volume basement housing an extended baggage handling facility

Images by Sean Mowatt.

› T he International Arrivals level with links to the existing Domtex arrivals level

› A n International Departures level linking to the existing International Terminal Departures Level, the Domtex retail mall and the multi-storey parking garage

› A n international transfer core concealed as a mezzanine floor

› A Domestic Departure level which extends from the Domtex Domestic Departure Level

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As part of the entrance elevation treatment, a glass canopy was designed in order to detract as little as possible from the façade, preserving full visibility of the façade while still achieving adequate shelter for pedestrians entering the building. Amongst others, the design of the façade was influenced by the use of materials found in the adjoining facades, the layout and space planning within the CTB, the existence of the new raised upper-airside road and elements and forms traditionally associated with flight.

Construction of the atrium and main entrance.

› A level housing the viewing deck and office accommodation › A plant room and overall roof-level The building was designed using a 15-metre structural grid, a concrete frame and post-tensioned slabs. The plant rooms and overall roof-structure were designed as a steel structure. The west facades, central atrium and viewing deck comprise architectural steelwork.

The entire building is serviced from the basement levels via the over-sized Baobab columns that rise through each of the floors to the plant rooms at roof-level.

Taking these guiding principles into account, the architects sought to develop a design that was sculptural in form, that comprised materials that would stand the test of time and that would complement the architecture found on the western precinct.

In the early stages of the conceptual design, the primary challenge presented by the atrium was marrying the dualities of function and an appropriate expression for what essentially would be the hub of the airport precinct. The integration of the atrium and main external entrance posed similar disparities.

The architectural expression implied a combination of forms, both centralised and dynamic, thus alluding to the aerodynamic symbolism. Extended 3D exploration of these complex relationships produced a tilted circular butterfly ‘winged’ roof, over a conical clerestory. In order to keep the clerestory free of heavy structural elements, the roof needed support from within the atrium space, via gigantic V-shaped concrete columns culminating in four split-vector steel members for every V-shaped column.

The concept of an organically shaped ceiling over the check-in counters grew out of a desire to express the concept of a flowing stream of people, once again in the idiom of the aerodynamic form. The added benefit of this form is a fragmentation of the ceiling over the vast expanse of the check-in hall – a space prone to looking bland and lacking of architectural form.

“ACSA is committed to empowerment and the transfer of skills. We therefore had an exceptionally large professional project team. The concept design, its development and the documentation of the CTB project is a joint venture between BAI and Siyakha Architects, BAI’s associated empowerment company, Osmond Lange Architects and Shabangu Architects. The CTB was not only a design challenge but it also provided an opportunity to demonstrate BAI’s ability to interface and communicate effectively and efficiently at all levels,” concludes Riley. <