Amsterdam Bijlmer ArenA StationEdit profile
Amsterdam Bijlmer ArenA Station forms part of a masterplan proposed by Dutch architect Pi de Bruijn. This included a 70m wide pedestrian boulevard aligned diagonally to the railway tracks to connect the two districts. Although initially the clients were just planning to add a pair of 200km/h tracks on the Amsterdam-Utrecht line alongside the existing ones, they agreed to rebuild a 2km stretch of existing railway with the sole aim of increasing the available height above the planned boulevard by almost 2m. Bijlmer Station had to remain open for the entire duration of construction. This had an important influence on the final design by Grimshaw and local practice Arcadis. A viaduct carrying the extra pair of tracks was constructed first and trains from an existing pair of tracks were then rerouted onto it, liberating the latter area as a construction site. This area of embankment was then excavated against temporary sheet piling installed to retain the adjacent “live” one. The process was repeated until there were eight new tracks running at the raised level. The roof enclosure followed sequentially. Every aspect of the design process was informed by the need to civilise these viaducts and to create a pleasant and safe ground level public space. To avoid a dark 100m long tunnel, the concrete structures were spaced apart. Each 20m span was supported at each end on just one column via an integrated cantilevered saddle. Arrays of columns were then aligned on axis with the boulevard to maximise visual connectivity from east to west. However, the most important decision concerned the roof design in general and its soffit treatment in particular. It is the modulation of this surface, its ribbons of roof glazing and its acoustically absorbent Oregon pine surfaces that convey civility from the perspective of the boulevard below. The base-element of the roof structure is a “V” shaped continuous hollow steel boom with steel arms cantilevered on either side to support all the roof glazing. The combined assembly is supported on a series of tubular “A” frames with only a single deep longitudinal stabiliser near the south end. Beyond their last supports these booms cantilever up to 18m thereby enhancing the sense of linearity and direction. The timber lined elements straddle each track-bed and are open at ridge level to help the station achieve climatic control through entirely passive means. The ridges assist natural ventilation and allow areas for pressure release in respect of 200k/h trains. Mesh screens positioned either side of ridge openings improve performance further by reducing wind velocity. Overlapping roofs and glazed screens help provide shelter from the elements. Roof glazing is positioned directly above platforms only. It constitutes less than a third of the roof area, but is sufficient to provide heat gain in winter. This means that only the independent retail units within the station require heating. In summer the station is naturally cooled and ventilated. Colder air is drawn into the station at boulevard level and then forced up through ridge openings by the stack effect principal alone. The lack of land to either side dictated a corresponding diagonal station hall facing the boulevard under the tracks. This diagonal slant dictated that the escalators, stair, lifts and roofs all be staggered. To signal the presence of the buried station hall from the surrounding area it was decided to gently arch each boom structure and to split all roof planes above the primary vertical circulation. The station’s angular aesthetic is derived from this methodology. The building has been warmly received in Amsterdam and is generally perceived as a catalyst for the development of the area on both sides of the tracks. Several related projects are already under way, including a parade of shops facing the station hall on the boulevard’s north side and the complete overhaul of the square immediately to the east currently cluttered with a series of temporary buildings.