Prime Tower, Zurich

Client Swiss Prime Site, Olten
Architects Annette Gigon / Mike Guyer, Zürich
Planning 2005-2008
Execution 2008-2011
Construction costs 355 Mio. Fr.
Services Load-bearing structure and excavation pit:
design phase
tender documentation phase
Photos Sebastian Grundgeir Photography
Gigon Guyer Architecs (model)
Engineering partner Dr. Schwartz Consulting, Zug
Freihofer & Partner, Zurich
Awards Award for good buildings City of Zurich 2011-2015
Publication - Design and Assessment of Structures as a Concerted Planning Process - Gebrauchsgrenzen hinterfragen - Windexponiert
Topics CommercialHigh-riseConcrete construction

The services included the planning of the load bearing structure, the foundations and the excavation pit for the development on the current Maag site. It consists of the approximately 130-metre-high Prime Tower, the seven-storey Cubus building, the seven-storey Platform building and the existing Diagonal building. The buildings are connected by a two-storey underground car park.

The Prime Tower consists of a reinforced concrete structure with centrally arranged cores, prefabricated columns and prestressed flat slabs. The cantilevered areas of the building are supported by inclined façade columns. The building is anchored in the Limmat gravel using large bored piles. The loads are transferred to the piles via solid concrete shear walls in the basement floors.

The Cubus and the Platform building consist of a reinforced concrete structure with flat slabs, columns and bracing cores. The existing Diagonal building consists of a steel frame structure lined with masonry. The load-bearing capacity for the new use is largely sufficient, as the building was planned for large payloads. However, the structure is insufficiently dimensioned for the transfer of horizontal loads. For this reason, the structural refurbishment measures are mainly limited to increasing the load-bearing capacity against the effects of earthquakes.