The Bochum-based architects Rübsamen + Partner who won the award in 1997 have created a design which focuses fully on the spatial effect, while the vaulting remains totally untouched. Instead, the glass floor takes up the lighting, with a mighty red wall with a yellow light cross at the end closing off the long subterranean space.
The design includes a concept by the Düsseldorf artist Eva-Maria Joeressen and a real-time sound installation by the composer Klaus Kessner. Architecture, light art and sound form a harmonious whole, undisturbed by advertising hoardings or information screens.
The subterranean hall, almost 90 metres in length, a width of 19 metres and a height of 14.5 metres, has one of the widest cross-sections ever made in free underground tunnelling. The ground rises almost imperceptibly and gently turns to the right. “Seen from one side, the immense volume opens up an impressive perspective to the passers-by coming down the stairs“, says the architect Dipl.-Ing Holger Rübsamen. “This is why we have decided to place the spatial effect itself in the centre of our design”.
Iridescent aluminium skin
To keep the ceiling free of all installations, the architects laid a laminated glass lighting floor over the entire length of the hall, with the slip-proof surface of the floor specially developed for this project. The glass panes are mounted on round adjustable stilt-type bearings with neoprene buffers. The mountings of the stilt-type bearings are anchored with 3,600 Upat UMV multicone resin anchors M12/80 and 160 Upat UMV multicone resin anchors M16/30 made of A4 stainless steel. The construction takes a live load of as much as 5 kN/m2 and can therefore also be used by rescue vehicles.
The indirect lighting rises from the 550 m² illuminated area; all fittings and furnitures, the glass lift cube and the signs are mounted on its surface according to reduced designs by the architects. The vault is fully clad over an area of 2,020 m² in greyishgreen aluminium sheeting, perforated for sound abatement, whose longitudinal stereotomy enhances the stretched appearance of the hall. A newly developed anodising process, lending the homogeneous surface a slightly iridescent colour appearance, was used in the making of the aluminium wall. In the grooves, the individually detachable sheet metal panels are bolted onto the rounded subframe made of capped aluminium profile sections with self-tapping screws. The holding elements of the subframe are fixed with 2,500 fischer long-shaft fixings SXS 10 x 16 F US made of A4 stainless steel. The fischer SXS is the first long-shaft fixing approved for single anchorings in cracked concrete.
The perspective accentuation of the space is enhanced by two delicate curved light bands underneath the ceiling of the vault which the artist Eva-Maria Joeressen has designed as a counterpoint to the brightly lit floor and the straightness of the tracks. At the end of the long stretched-out hall, they appear to link up with the arms of a yellow light cross which Joeressen has integrated into the almost room-high red wall as an abstracted image of the road intersection above ground: the cross becomes the signet of the space, forming its spatial end and standing in its perspective focus. The full effect of this design element has also been made possible only by a fixing solution by fischer. The yellow glass elements forming the cross are fixed by 60 fischer FZP-G glass fittings. The glass elements consist of 10 mm thick ESG-H with translucent screen printing on the back. Like inlay, the glass element lies flush with the level of the enamelled metal panels.
Sound installation in real time
Similar to the physical design of the underground station referring to the spatial conditions, the permanent sound installation by composer Klaus Kessner takes up the authentic conditions prevailing at the place and the movements taking place there. Anyone waiting for the train at the platform will hear unusual and eerie sounds coming from loudspeakers concealed in the walls of the vault and fed by invisible microphones which Kessner has installed at various points inside the station. The microphones pick up the voices of the passers-by and the noises of the trains and the road traffic which a computer transposes into an ever-changing sound image.