Linking two districts which are currently divided by the railway, Bijlmer-Arena will be one of the largest stations in the Netherlands and form a major interchange with metro and bus routes

Rob Steenhuis,
Managing Director,
Arcadis Architecten

FUNDAMENTAL to the architect's brief for rebuilding the station at Amsterdam Bijlmer-Arena was the requirement that it should act as a local landmark, be easy to use and incorporate a variety of commercial activities. The result combines function, ambition and vision, with an elegance produced through a successful collaboration between two architectural practices, Grimshaw and Arcadis.

After three years of discussions, ProRail, Netherlands Railways, the city council and Arcadis reached agreement on the positioning of the railway to satisfy the needs of all stakeholders. As well as the original double-track metro and two mainline tracks, an additional four tracks have been provided for ProRail, with a flyover improving the connections to and from Schiphol Airport as part of the quadrupling of the Utrecht - Amsterdam route. The tracks have been raised almost 2 m above their previous level, putting the platforms 10 m above grade and creating large voids between the viaducts which will maximise daylight penetration to create a well-lit and secure environment below.

Design work began in September 1997, and once the initial draft design was agreed, the architects' contributions complemented each other to create a building which is much more than the sum of its parts. Jan van Belkum was lead architect for Arcadis and Neven Sidor for Grimshaw. Arcadis has been responsible for the infrastructure engineering and technical installations throughout the project.

The urban development masterplan drawn up by Pi de Bruijn centres on a 70 m wide boulevard located diagonally beneath the tracks. As well as providing a link to the station, this ensures that the areas to either side of the tracks have sufficient connectivity as part of the development of cinemas, shopping malls, leisure facilities, offices and schools around the ArenA stadium, regeneration which will see the number of passengers rise to 60 000 per day, with peak flows of 25 000 in 90 min when AFC Ajax are playing.

The station had to remain fully operational throughout reconstruction. This was achieved by phased construction of four separate concrete viaducts and five self-supporting steel roof elements running the length of the roof. Each bay of the viaduct comprises a pair of large round columns with widened heads, supporting four interconnected 26 m hollow prefabricated beams, with cantilevered platform slabs supported by steel props to either side. The columns maintain the sightlines, standing parallel to the main axis of the boulevard.

Bold design

The station hall is located on the south side of the boulevard, where space has been created for retail units, cafés and a passageway to the bus station beyond. The retail zone continues on the north side of the boulevard, with a parade of shops running to the stadium.

At rail level the station has three 14·5m wide island platforms, with two 7 m single platforms serving the outer tracks. All are 344 m long, except the middle island used by the metro, which is only 155 m in length.

NS standards dictate that canopies should be at least 200 m long, and the form of the roof is key to the station architecture, as the most visible element of the building. Designed to express the dynamics and comfort of high speed travel, the roof is aligned with the diagonal boulevard and features a substantial split in its longitudinal silhouette to draw attention to the escalators linking the platforms with ground level.

Viewed from the boulevard, the timber and steel soffit of the roof structure provides the bold public face of the station as it flies overhead. Each pair of tracks is capped with a matching 200 m roof vault, and each vault is linked to the next to form an overall structure of four identical parallel segments. Each of these is supported in turn by four raking A-frame columns, with a special stabiliser element at the southern end, and features 18 m cantilevers beyond the last structural support which amplify the sense of linearity and direction.

The tubular steel A-frames have paired pin connections at ground level and support a continuous V-shaped plate-steel fabricated beam that varies in height from 1 700 to 4 500 mm and in width from 800 to 1 850 mm. The underside of the V-beam rises above platform level from a height of 3·10 m at the perimeter to 6·50 m at the centre, and the highest point of the roof is nearly 20 m above platform level.

Exposed steel ribs are fixed either side of the V-beam at 3·8 m centres to support platform glazing as well as solid roof areas, which are constructed as an insulated double-skin metal deck with perforated acoustic cladding of Oregon pine on the inside. For cost reasons all roof members have been designed to have the same angle and length, with the variations in the profile of the V-beam accommodated in the clear opening that runs along the apex of each vault. The opening is framed with perforated metal mesh panels varying in height from 800 to 2 500 mm at the highest point of the roof. Fins capture diffuse light glowing through each roof apex at night, enhancing the prominence of the station as a unique focal point on the skyline.

Considerable research has been undertaken into passenger flows, wind pressure, vibration, acoustics, passenger security, maintenance and management, and this informed the design in a number of ways. Air vents in the roof and side elevations reduce overpressure caused by the wind and express trains, while the vertical mesh panels minimise wind-driven rain penetration.

Acoustic attenuation has been achieved with absorbent materials behind the perforated timber soffits, acoustic sheeting placed alongside trackbeds, and curved acoustic sheeting underneath concrete viaducts, which are completely separate from the roof structure to isolate dynamic train movements.

One of the main aims was to design a station which feels secure both day and night. Light grey mosaic tiles and terracotta panels protect the concrete columns and perimeter walls from graffiti, and long voids have been cut into platforms to relieve the 100 m overshadowed section of boulevard below. These voids provide extra visual connectivity between platforms and ground level, and allow daylight to reach the boulevard and bus station areas.

The same concerns influenced the design of the station hall located at the heart of the project. Adjacent to the bus station, this will provide a wide variety of commercial facilities including a large cafeteria and restaurant. Future commercial development will be located along the north side of the boulevard, as well as opposite the bus station below the viaduct.

The station is due be completed by September 2007, along with the section of boulevard from the eastern side of the station to the Ajax stadium.

• CAPTION: Exposed steel ribs at 3·8 m centres support platform glazing and solid roof areas
• CAPTION: A 70 m wide boulevard is being created to link the east and west sides of the railway as part of an urban regeneration scheme
• CAPTION: The main building contractor for the project is Besix, and the steel structure has been supplied and assembled by Victor Buyck Steel Construction
• CAPTION: The sequential construction of four parallel concrete viaducts allowed trains to be diverted while the former embankment was removed
• Photos: Robert Oestermans