Hekla Tower in Paris

Part of the development of the La Défense business district, this 220 m high tower, which is intelligent and adaptable, is made up of 48 floors, 37 of which are offices and 5 of which are services (76,000 m² – 1,700 m² of current office space). Three levels house “L’espace Club”, topped by a rooftop with terraces or loggias on each floor. The top of the tower offers magnificent panoramic views of Paris and La Défense through a three-dimensional cap.

The mission of the bureau Greisch for this project consists in the study of the stability of the North facade and the roof cap.

The study of the northern tip of the building focuses on the stability of the facade projections called “jouées” and that of the external staircase, which is almost 30 m high. The design is guided by the control of deformations with a double objective: to reconcile the thermal expansion movements of the framework with the problems of settling, inherent in a high-rise building, while respecting strict criteria for the deformations of the facades.

To achieve this, the staircase structure is entirely suspended on a single level. This singular choice allows its movements and those of the building to be independent.

The terraces on the upper floors are intended for the creation of a landscaped garden where tall trees are to be planted. A cover made of metal framework and facade elements on several levels dresses this volume while leaving a large opening at the top for the passage of the cleaning equipment.

All the interventions of the bureau Greisch are also directed by the need for a perfect integration of the structure, deliberately visible, to the global architectural concept. This is achieved by a “made to measure” dimensioning with hidden assemblies using several times elements of variable geometry and/or reconstituted by welding (PRS).