Situated close to Hardbrücke railway station in Zürich, Gigon & Guyer Architekten’s Prime Tower and its three annexes, the Platform, Cubus and refurbished Diagonal, are part of a former industrial site that is being developed as a business and residential district, masterplanned by Diener & Diener. Currently the tallest building in Switzerland, the 126-metre structure has an irregular octagonal plan with retail spaces at ground level, offices on the upper floors, and a restaurant, lounge and bar on the top floor.
The cores and emergency stairs are positioned to allow up to four tenants to occupy each floor, or alternatively, for a single business to take several floors with internal atriums and staircases. Additional office space is created on the higher and therefore more sought-after floors, by the projecting floor plates. These also result in greater spatial diversity. The cantilevered projections are supported by slanting reinforced concrete columns, which run over two- or three-storeys. Green-coloured, triple-glazed, frameless window units give the polygonal structure a multifaceted appearance. To enhance working conditions, and meet the requirements for smoke ventilation, alternating windows can be opened parallel to the building.
Architect: Gigon/Guyer Architekten; structure: Walt & Galmarini, Dr Schwartz Consulting, Dr Lüchinger & Meyer Bauingenieure, Bänzinger Partner, Richterswil and Freihofer & Partner, services: Hefti Hess Martingnoni, PB P Berchtold, Hans Abicht; landscape: Schweingruber Zulauf; main contractor: Losinger Construction, Karl Steiner; photos: Thies Wachter.
First published in AT228, May 2012