ArcelorMittal honoured with German Engineering Award for Steel Construction 2017

At the BAU trade fair in Munich, the Steel Construction Forum (Bauforum Stahl) presented ArcelorMittal with an award for innovative building using steel beams in composite construction (composite slim floor beams, CoSFB). The slim floor beams made in high-strength steel facilitate safe, fast and cost-efficient building when combined with deep rolled profiled panels for floor construction, such as the Galerie Kons in Luxembourg.

The Consortium for Office and Commercial Buildings (KONS), which included ArcelorMittal Construction and ArcelorMittal Europe – Long Products, Stahlbau Ziemann GmbH and M3 Architects, received the German Engineering Award for Steel Construction from the Steel Construction Forum. During the modernisation of the Galerie Kons, a popular shopping mall in the city of Luxembourg, ArcelorMittal used trapezoidal sheets and innovative composite steel construction to show that structural steelwork can combine the image of safe, modern and efficient with the demand for innovation.

The reasons given by the Steel Construction Forum for the award stated, “With the integrated CoSFB beams, it is possible to utilise almost the entire floor height for the flush beams. The static load-carrying capacity thus achieved significantly improves span widths, cost-effectiveness and resource efficiency of the flat floor system. The minimised use of resources demonstrates a high degree of engineering knowledge and clearly shows that, even for apparently mundane tasks, engineering input is a key factor for a project’s success.”

Mathias Braun from ArcelorMittal Europe – Long Products and Christoph Radermacher from ArcelorMittal Construction said, “The advantages of this composite construction method can be seen in the reduction of its dead load and the floor height, the outsourcing of production processes to the structural steel workshop, fewer storage and unloading zones, less site traffic and relief of strain on the cranes.”

From hotel to shopping mall

The Galerie Kons was originally built as a hotel directly opposite the main station. After the Second World War, the building was extended and then radically remodelled in the 1990s. Now the Galerie is being modernised. The Galerie Kons site offers approximately 4,400 m2 of floor space. It will house mainly offices and retail outlets when it opens in spring 2017. There is a large parking area in the basement and apartments in the somewhat quieter section.

It was necessary to demolish and remove approximately 83,000 cubic metres of construction volume while 32,000 cubic metres of enclosed space were given a facelift.

The solution was composite steel floors

In addition to the conventional construction method using cast-in-place concrete, which was not sustainable in terms of time and also material logistics, systems using precast floor slabs or prestressed concrete hollow beams were also investigated. Although they facilitate fast laying, they exceeded either the permissible dead load or the maximum construction height.

Ultimately, the solution was provided by a floor system using composite steel beams in the high-strength grades S355 and S460 by ArcelorMittal Europe – Long Products which were integrated into the floor. To comply with the mandatory fire resistance time of 90 minutes, the composite beams were filled with additional reinforcement in the chambers. The deep rolled profiled panels provided by ArcelorMittal Construction (Cofraplus 220) bear the concrete load without further support. The Cofraplus profiles were supplemented by an additional 10 cm thick concrete topping and reinforcement.

BREEAM certificate for sustainability

The specifications for the remodelling of Galerie Kons presented the engineers with major challenges. They had to comply with specifications for fire and noise control, energy efficiency and building regulations. The requirements of the BREEAM certificate, a demonstration of the future building’s sustainability, also had to be implemented.

Finally, the site was located in a popular area of the capital with high-traffic and built-up lanes so it was necessary to adapt the site logistics to the work process to ensure that construction ran smoothly. The tight supply chain was coordinated from the rolling dates onwards due to limited storage space and ambitious delivery dates.