Banking on Frankfurt

Architectural Review, The, May, 2005 by Layla Dawson

For an architectural studio with a small oeuvre, within limited geographical boundaries, Sauerbruch Hutton have an exceptionally high profile, due perhaps to their concentrated architectural vocabulary which makes their projects instantly recognisable. Their latest competition win, for an extension to the KfW Banking Group headquarters in Frankfurt am Main, displays yet again the curves and colours characteristic of their work since their Berlin GSW Headquarters (AR August 2000), Biberach Pharmacological Research Centre (AR August 2003) and Dessau Federal Environmental Agency, due to be completed later this year.

West Arcade starts on site in 2006 and completion is planned for 2008. It is essentially an office building with 550 workstations, conference facilities and electronic data processing centres. A four-level podium structure, with a sheltered arcade walkway, will connect at eaves height to the existing bank building and then extend along the Zeppelinallee road line with an asymmetrical curved and three pronged footprint. A 14-storey, 54m high, tower placed on this irregular Y-shaped base has the plan of a leaf. This configuration is a friendly gesture to a neighbouring high-rise so that it can maintain its uninterrupted view into the nearby park. Right-angles seem to be anathema to Sauerbruch Hutton. As a result, though they are all large-scale complexes, their buildings have never appeared aggressive. The pattern of stacked floors, which might have become monotonous, is always broken by a patchwork cover of subtle colour variations. In West Arcade, colours will be warm hues of grey, from blue-grey and green-grey, to red. A double-skin facade will consist of external coloured or transparent glass, vertical perforated metal sun louvres in similar hues hanging within the sandwich, and internal clear glazing. On each floor this facade is divided into two 'boxes'. The bottom box unit allows external air to enter into the sandwich. As the air warms it rises and leaves the space via ventilation in the top box unit. This filtering system reduces street noise and wind gusting effects.

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The site in the west end of Frankfurt is near the Palm Garden, a horticultural park of exotic plants and greenhouses. The new building's foyer is positioned on the north side so that, on entering the building, visitors have an unhindered view into the park. In line with current European thinking on empowering building users, and making them more environmentally responsible, the architects are hoping to persuade the client to use solar energy. Compact volume, high insulation, efficient shading against glare and heat gain, and manually operated openings for ventilation are all part of a passive, sustainable building technology concept.

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