Office and residential tower, Chêne-Bourg
Location Chêne-Bourg, Switzerland
Date 2014

Competition, 5th prize

Gross floor area 18'000 m²

Grégoire Martin
Julien Charmion-Henry
Celia Laserna
Gabriela Pratas
Vincent Blanc-Tailleur

If the tower block is an urban form that evokes height above all, its relation to the ground is vital for the good functioning of the programmes allotted to it. The two stabilising wings play a key role here in this respect. First, they concretise the links between the main public stopping space of the square and the building’s sides. Second, they invite pedestrians in by indicating the location of the entrances.

The north wing, partly retracing the northern alignment dictated by the district’s localised plan, projects outwards towards the green lane and one of the train station entrances. It accommodates, under a sheltered porch, the entrance to the apartments. On a house-like scale, it aims to be as domestic as possible. The south wing detaches itself from the verticality of the south-facing facade to form a special connection with the future Place de la Gravière. Their combined energies define a high quality public space.

In this mix of classicism and flexibility, the search for a suitable architectural language is intuitive. On the one hand, it alludes to an ancient construction method, used only for stone, in which lintels are supported by pillars and which incorporates elements of reduced size and complexity. This building method stems from a structural requirement, focusing first on the solid parts before creating the openings. On the other hand, it is inspired by a more recent typology that already uses prefabricated concrete but with a different dialectic, since it takes the opening as its starting point to form an element that is both frame and window. This construction method originates from the attractiveness that an opening in a wall brings to the quality of the spaces on the other side of it.

An expression of both openings and structure, the I-shape designed element develops a scale and a configuration, like a window, proportionate to the stature of the building’s residents. It also cuts down on linear joints susceptible to rapid degradation. Its I-shape evokes the pillar, reinterprets the lintel which, made of reinforced concrete, offers solid support for the overhangs. It redirects the vertical force lines away from the joints and creates wings on either side of the pillar whose varying width defines the sizes of the openings. The classicism lies in the systematic interconnection of bases, pillars and lintels, while flexibility is expressed through the different deployment of the tower block’s set back wings.