Alta Tower in Le Havre by Hamonic + Masson

The centre of Le Havre is one of the most impressive post-war building ensembles in Europe. After almost complete destruction during the war, Auguste Perret designed a residential and business district that still sets standards today in terms of structural rigour and usability. In 1982, Oscar Niemeyer added a concert hall – popularly known as the Vulcan – and a library to the city centre.

Hamonic + Masson & Associés' Alta Tower incorporates elements of both: Perret's multi-storey buildings with their uniform grid, and Niemeyer's solitary buildings with their bold dynamism. In 2015, the Parisian firm won the competition for the new building against Rudy Ricciotti and Herzog & de Meuron. The 55-metre-high, 17-storey tower stands at the intersection of two twisting street grids. This gave the architects the challenge of creating something formally special.

The balconies cantilever up to 3 m at the corners of the building. © Clément Bonnérat

The tower contains 64 three- to five-room apartments and a crèche with more than 60 places on the ground floor. It was a challenge for the structural engineers to rotate the building by almost 90° – especially as the apartments inside were to be column-free and their floor plans were to be variably configurable. A central access core, approximately 6 x 6 m, supports the floor slabs, which extend to the facades without columns in the upper facades. The 1.5 to 3 m cantilevered balcony slabs are connected to this on the outside. They are made of pre-stressed concrete to keep them as slender as possible.