Tours Duo: two towers of a singular shape optimised with ArcelorMittal steel

Detailed information

The ‘summit’ of the Rive Gauche redevelopment

This new mixed-use development on the Rive Gauche (Left Bank) in Paris completes the urban redevelopment plan that had been ongoing for the past 20 years. It was built on a 5000 m² plot of former industrial wasteland in the French capital’s 13th arrondissement. Situated close to the city’s Boulevard Périphérique ring road and the Avenue de France, the two high-rise buildings ascend in a V-shape from a common base open to the public and offer almost 110 000 m² of offices spaces and shops, a four-star hotel with a bar and a panoramic restaurant, an auditorium, green terraces, and a publicly accessible covered rooftop area with views over the heart of Paris.

Architect Jean Nouvel, creator of Parisian landmarks like the Musée du Quai Branly and the Philharmonie de Paris, designed the Tours Duo as the summit of this redevelopment project. Their inclinations make them visible from many different places around the city and allow us to enjoy the reflections of the adjacent railways and buildings on their facades. Their shapes make them appear dynamic and almost human – as though they are two neighbours having a chat.

Duo 1: a structural solution featuring ArcelorMittal steel

The five-degree slope of the 39-storey Duo 1 and the tiers of Duo 2 (28 storeys) required inventiveness in terms of procedures, construction methods, and materials employed. The structure of the higher Duo 1 tower includes ArcelorMittal steel.

Duo 1 has a composite steel and concrete structure. Around a concrete core with unusually thick walls (necessary due to the inclination), floors 16 to 28 were constructed with a steel frame featuring ArcelorMittal steel.

The shape of the tower required structural optimisation, which included limiting the floor-to-ceiling heights as much as possible within the norms established in current standards. Therefore, the space required for false ceilings and floor thicknesses had to be reduced as much as possible while integrating the technical systems (HVAC, electricity, etc.) into the floor beams. The solution lay in the use of composite floors and steel beams with web openings for the technical ducts – and ArcelorMittal provided the suitable products for these requirements.

For the steel frames of floors 16 to 28, ArcelorMittal Europe – Long Products supplied more than 1000 tonnes of HD sections used as columns and IPE, HEA, and B sections employed as floor beams that were fabricated and customised for the project at ArcelorMittal’s Steligence® Fabrication Centre.

ArcelorMittal Construction’s Cofraplus® 60 composite flooring sheets helped to reduce the floor thickness – an important factor in the structural optimisation design.

Apart from material supply, ArcelorMittal provided technical assistance. ArcelorMittal’s engineering team assisted with the cost optimisation of the steel frame by proposing rolled sections instead of welded sections and finding a solution for the elimination of reinforcements in the beams’ web openings.

Digitalisation and sustainable building certification

The project made extensive use of BIM (Building Information Modelling) which provided important advantages: a digital twin was created to facilitate maintenance, optimise space, and contribute to making Tours Duo an efficient and sustainable building.

The Tours Duo attained three sustainable building certifications (WELL Building Standard™ - Platinum, LEED® - Platinum, and NF BT HQE Sustainable Building - Exceptional) and two labels (Effinergie+ and WiredScore® - Platinum) covering criteria related to respect for the environment and the well-being of future occupants.