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The 140-meter Diamantone, the tallest steel structure in Italy

Located in the Centro Direzionale di Milano, a major business district in Milan, the 140-meter Diamantone or Diamond Tower, became the tallest steel structure in Italy, and the country’s third tallest building, when it was completed in 2012. Diamantone, named for its irregular, faceted form that references a diamond, is the tallest of the three towers built on this plot, with the additional two buildings known as the Diamantini or the Small Diamonds. They were constructed as part of the extensive urban redevelopment program in Milan, known as the Progetto Porta Nuova.

ArcelorMittal Solutions Fire 
Heavies High strengh 
Bracing concrete core     sprayed
Columns perimeter columns: HD360/HD400 S460M   sprayed/board
Floor solutions   S355 cellular beams sprayed


Steel structure

Designed with steel columns, composite flooring, and a reinforced concrete core, the building is lighter than a conventional reinforced concrete structure. High strength steel was used in the structure, which has a higher yield strength compared to conventional, S235 grade steel. This resulted in up to a 50% reduction in the total material cost. Since the cost of the S460 M grade rolled sections is just 10-15 % higher than S235 grade material, 30-40% of the savings could be achieved exclusively in the material costs.

It also allowed column-free office space, enabling a preferential shallow foundation and providing significant advantages in terms of transportation of materials on-site.

The additional savings were achieved through a reduction in the amount of welding material, corrosion protection and transportation costs using less structural material and less surface area.

ArcelorMittal steel sections

The composite beams provided for Diamantone, were S355 grade, IPE and HE sections that contain several openings in the web for the integration of building services and can achieve spans of up to 11 meters. 1 800 IPE and HE composite floor beams were provided, with a total combined length of 13 520 meters. The steel deck of the composite floors had an undercut geometry that contributed to the reinforcement, allowing for a floor thickness of only 15-20cm. A total of 26 000m2 of composite decking was used.

Avoiding traffic impact

The challenges of a major construction project in a dense urban environment includes heavy traffic, reduced space for unloading, and virtually no storage space. Through a detailed production and logistics plan, the 3 800 tonnes of steel elements were delivered in 150 separate loads with limited interruptions to regular traffic and only 2 deliveries a day. Through these sustainable and efficient design and construction methods, Diamantone achieved a LEED Gold certification, one of the highest ratings recognised by the Green Building Council.

Height: 140m (459ft)
Number of Floors: 31
Gross floor area: 290 000m2
Building Function: Office
Structural material: Steel columns with composite floors a reinforced concrete core
Completion: 2012
Architect: Kohn Pedersen Fox Associates Pc
Structural Engineer and Work Supervisor’s technical support: ARUP
General Contractor: ATI CMB/UNIECO
ArcelorMittal Steel: 3 800 tonnes
Fabricator: StahlBau Pichler in Bozen/Bolzano

© Lorenzo de Simone