ArcelorMittal’s composite flooring deck and structural sections add lightness and transparency to Cargolux’s high tech headquarters

Detailed information

Architectural design: modern lines and transparency

In 2015, the German architectural office AS+P Albert Speer & Partner won the design competition for the new Cargolux Headquarters building.

Their concept picks up the linearity of the surrounding buildings and is dominated by the two-storey square ring that seems to float over the main building and the flight simulator training hall, providing office and conference spaces. With each side measuring 80 m, this square volume rests on only four access cores, creating cantilevers of more than 40 m.  

At ground floor level, the highlight is a glazed cube - the 9-metre-high flight simulator hall that rises from the basement and makes the simulators visible to the public from the outside. The backbone of the whole complex is a two-storey building with office spaces and training facilities that connects to a semi-subterranean car park with 350 parking spaces organised over six half levels.

Different structural concepts for each building volume

The structural systems and materials employed depended on the different building volumes’ function and design. They range from steel structures over composite structures to reinforced concrete structures.

The most striking of the building’s constructive volumes is the square office ring that tops the architectural complex. Weight reduction was the main objective in its structural concept in order to limit deformation and comply with the criteria for the glazing.

The load bearing structure of this two-storey volume that forms a square measuring 78 x 78 m consists of 1270 tonnes of steel in grades S355 and high strength HISTAR® 460 produced by ArcelorMittal Europe – Long Products. The structural concept is based on Pratt trusses in the facades composed of H and W profiles in the chords, square tubes as columns, and rectangular tubes as tensioned diagonals, all with sections of 300 mm. Contributing to the lightness, the flooring structure with a height of just 12 cm was realised with Cofrastra® 40 composite flooring deck supplied by ArcelorMittal Construction. The flooring sheets are supported and connected to the facade trusses by HE 500 B beams in a grid of 4.05 m with spans of 12.5 m.

Given the complex and repetitive assembly details and exterior fixings, the use of 3D modelling with BIM technology proved key to ensuring the geometric coordination of the structure between the designers and the contractors.

The pilot training centre, where the flight simulators are located, is realised in a steel structure that blends in the fully glazed, transparent curtain wall facades. It consists of circular columns (273/10) and perforated HE 800 B roofing beams (S355) that incorporate technical installations and support the metal roofing panels. The roofing beams are placed at 6.075 m distances, covering spans up to 22 m.

The core building of the complex - with office spaces, training facilities, and technical installations - has a reinforced concrete structure.

The self-supporting structure of the open car park, which was the first metal structure to be erected on site, is constructed in a steel-concrete composite frame with IPE 400 beams spaced 2.5 m and spanning 16.5 m. The 12 cm high composite flooring system is made with Cofraplus® 60 steel deck supplied by ArcelorMittal Construction. It offers 7000 m2 over a six half-level layout, with each half level equipped with a 15 m long self-supporting beam. The car park has a green roof and is partly integrated into the site topography.

The metal footbridge that connects the new headquarters building with the existing maintenance hangars also houses the company’s cafeteria. Two Vierendeel trusses made of square tubes (300/300 mm) connected at the top with regularly perforated HE 500 B beams allow the structure to bridge the access road with a span of 15 m.

An “engineering masterpiece”

Alexander Flassak, CEO of Cargolux, proudly calls the building an engineering masterpiece. He not only refers to the sophisticated structural design, but also to the thorough construction planning and site operations that had to be carried out in a short time frame and under certain constraints due to its location close to the airport. All of these factors required close collaboration of all parties involved. The building was completed at the end of 2019, after 23 months of construction works.

A total of 1500 tonnes of structural steel, 10 000 m3 of concrete, and 1100 tonnes of reinforcing steel were used to build this modern 10 000 m2 multi-purpose company headquarters.