Enjoy fantastic view of New York’s skyline thanks to ArcelorMittal Differdange steel

May 29, 2015 - The observatory of the One World Trade Center – One World Observatory - opens its doors today to the public. On this occasion, let’s go back to the construction of the tower, which contains more than 20,000 tonnes of ArcelorMittal steel of which some 12,500 tonnes of HISTAR® beams from our Differdange’s plant.

© Skidmore, Owings & Merill LLP - dbox Studio

The 4th highest skyscraper in the world

With its tapering triangular form, the One World Trade Center is New York’s new visual landmark and North America’s highest building, 14 years after 9/11. Previously named Freedom Tower, it was built between 2006 and 2014 and inaugurated in November 2014.

The tower’s structure is designed around a strong, surrounding steel frame made of beams and columns. The reinforced concrete core wall system at the centre of the tower acts as the main spine and provides support for gravitational loads as well as resistance to wind and seismic forces.

Le One World Center en chiffres :

  • 543 m de high
  • 104 floors
  • 54 high-speed elevator
  • 61 m concrete base
  • more than 325 000 m² of usable floor aera
  • 5100 m² of retail space

Europe-US collaboration for this iconic building

ArcelorMittal Europe and ArcelorMittal USA both supplied steel for this huge project.

ArcelorMittal Europe – Long Products supplied structural steel sections for the tower’s steel frame. More than 12,500 tonnes of HISTAR® beams and columns produced in Differdange (Luxembourg) were provided for the perimeter of the tower’s base, and sold through ArcelorMittal International North America.

ArcelorMittal USA provided 10,000 tonnes of steel plates produced in Coatesville that were used for the fabrication of girders supporting the building’s foundation, floor support girders and the construction of the antenna. The plates were also used in the foundation of the subway system beneath the building.

The “Freedom beams” made with HISTAR®

The so-called “Freedom beams” were only produced for the construction of the One World Trade Center. They are 9 to 17 metres long, weigh up to 1,1 tonne per metre, and are made out of HISTAR® grade 65 steel. ArcelorMittal Differdange is the only steel mill in the world that can produce these beams.

HISTAR® steels are structural grades with alloy content, combining high strength, good toughness and superior weldability. HISTAR® mechanical properties can reduce construction weight by 25-50% depending on structural lay-out and naturally provide high strength and exceptional durability. These characteristics are achieved by a quenching-and-self-tempering (QST) process available in Differdange only at the end of the rolling line, which considerably improves the mechanical and physical properties of the steel shapes.