NEW BNL HEADQUARTERS - ROME
High-end office building composed by 4 basement/podium levels (part underground and part open on one side) hosting parking, storage and technical spaces, plus 12 above grade storeys hosting office spaces and ancillary functions. The roofs are used for technical spaces, terraces and a photovoltaic field. A total of approx. 72.000 m2 of gross floor area, with the following subdivision:
23.000 m2 basement/podium levels;
45.000 m2 above grade floors;
4.000 m2 roofs.
The area has a high grade of seismicity according to the Italian Code. The building features a length of approx. 220 m; a structural cuts this length, by allowing longitudinal slow differential displacements but stiffly connecting the two parts under earthquake actions; the joint is equipped with visco-elastic STU (shock transmitter units). The joint is placed in the area where the building features a wide opening that allows for the sight of the existing historical water tower, protected by the Cultural Heritage Authority. On the south end, the building features a “bow” shaped volume, cantilevering for the full length of three spans or 27m.
The basement/podium is built into an excavation surrounded by concrete diaphragms; the structures are made of concrete, using flat slab floors on columns at typical grid spacing 12x9 m. Foundations are under water table level, and are based on bored piles connected by a water-tight concrete slab.
Above grade structures are of composite steel-concrete type:
- tridimensional steel frames, stabilized by concrete stair/elevator cores; the concrete slab acts as an horizontal diaphragm connecting all elements; typical grid is 12x9 m: main beams @9 m are perforated to allow for MEP penetrations, according to a detailed fully integrated design process;
- floor slabs are cast over corrugated steel sheets; the sheet panels are of deep rib type, allowing for spans up to 9 m; concrete top is connected to beams by connection studs in order to form a composite-behaviour system;
- stairs and elevator cores are made in reinforced concrete, and they act as the stability system for horizontal actions as well as support for the floors;
- the “bow” area features a truss mega-structure deployed along the facades.