A new Transportation Centre forms the hub of Inchon International Airport, South Korea
In the 19th century, the railway station was an essential civic landmark - a symbol of prosperity. Today, and particularly for East Asian countries, the airport plays this role.
The new Inchon International Airport in South Korea, with its Transportation Centre designed by Terry Farrell & Partners, has all the qualities of a landmark.
The airport was one of the world's largest construction projects and its scale is vast.
Work began in 1992 to reclaim a tidal marshland site between what were once two islands.Mountains were excavated as landfill to create a new airport zone measuring 8km x 6km. It is designed to serve Seoul (population more than 20 million and rising) and 43 other major Asian cities, with a projected capacity of around six million passengers a year. There are two runways, with space for a potential five, and a 50-gate passenger terminal, the first of several planned.
The new Transportation Centre is bi-laterally symmetrical about its north-south axis; it gives an identifiable visual focus to the vast and amorphous array of airport infrastructure, including the terminal which curves around it in an enormous arc.
The purpose of the centre is to bring together a number of transport systems, linking them and making them easily accessible to passengers. Most systems have been placed below ground level, so that the centre sits in a landscaped park. Its roof and swelling walls form an organic shape - reminiscent perhaps of a Korean fan or a gigantic crown-cap bottle opener - which give the airport an identifiable form when seen from the air or by those arriving by road or rail.
The roof and curved walls cover the main public concourse and hub of transport activity - the Great Hall, a huge vaulted atrium spanning 180m. It is formed by a steel structure of arched portal-frame trusses partly glazed and partly roofed with stainlesssteel panels. Swelling glazed walls cut into the hall on the east and west sides to form a baroque sequence of fluid shapes, overhanging platforms and concourses interlinked with balconies, escalators and ramps. On the south facade, the roof arches to create a vast glazed wall looking out on to the airport and giving views of terminal buildings and arriving and departing aircraft.
The layout is simple. All passengers pass through the Great Hall whose large, naturally lit spaces are visible from all arrival points.
A series of basement levels houses five rail systems (a new Seoul subway line, standard train, high-speed train and local train to the airport business centre); a bus and coach station; taxi, car rental, hotel and tour-bus pick-up points. The complex car-parking requirements of passengers, visiting public, employees, taxis, rental cars and buses are accommodated in 5,000 spaces in three basement levels.
In Farrell's original design, the flightcontrol tower, an organic bird-like form, hovered over the roof, supported on delicate legs and reached by a system of elevators.
This was not needed after the number of runways was reduced, and it was replaced by a 'pod' with a glazed underside which rests on three legs. The pod, together with an oculus in the roof below it, acts as an aerofoil ventilator and solar accelerator to ventilate the building naturally in summer.
The interior is fitted out in a restrained palette of materials - silver-grey fluorocarbon-coated aluminium wall panels, grey granite floors, clear glass curtain walls and satin stainless-steel cladding to the underside of the monorail.
While the basements that house the transport infrastructure are constructed of cast in-situ concrete, the enclosure of the Great Hall is a steel structure of arched portal-frame trusses. Using more than 6,300 tonnes of steel, the main frame was fabricated in two sections on the south side of the site while the concrete sub-structure was being cast, and subsequently slid on tracks into its final resting place.
The Transportation Centre and the airport were finished in time to be one of the first sights that greeted air passengers arriving for the World Cup in June.
A roof covered with a rainscreen of stainless steel panels
The roof spans 180m and is formed by a series of arched portal frame trusses, over 6m deep, which are formed of welded tubular members. The complex form was initially modelled by hand and 'sliced' into sections that could subsequently be rationalised by a CATIA program - commonly used in car design.
The organic curved forms of roof and walls are covered with a rainscreen system of triangular stainless-steel panels; the triangular shape was chosen as it would accommodate the complex three-dimensional curves of the roof and wall planes.
The roof covering is supported by a 600mm-deep steel space frame that rests on the main trusses and determines the curve of the roof. It is overlaid with absorbent material and an EPDM membrane.
Spigots are fixed to the nodes of the space frame and penetrate the membrane; they are fitted with shoes and proprietary rubber gaskets to create a waterproof lining. The spigots are topped with circular steel nodes. Z-shaped legs at the corners of the stainless-steel panels are bolted to the nodes; they are set with edges 50mm apart and adjusted by hand to fine-tune the curve of the roof.
The 12mm-thick panels are composed of an aluminium honeycomb core, bonded to inner and outer sheets of stainless steel.
Stainless steel was chosen for its resistance to weathering in a harsh and humid climate which experiences extremes of temperature and is exposed to marine salts.
A curved rooflight at the apex of the roof consists of fritted glass panels with solar-control coatings; the panels are flat and the frames are faceted to create the curved surfaces.
ARCHITECT Terry Farrell & Partners
EXECUTIVE ARCHITECT Samoo Architects & Engineers
STRUCTURAL, MECHANICAL & TRANSPORT ENGINEER DMJM