The project concerns the construction of the new corporate headquarters of ENI, Italy’s energy giant, in Milan.

Located in the municipality of San Donato Milanese in the city’s southeast, the headquarters will be based on a design by Morphosis Architects, the U.S. architecture firm led by Pritzker Prize winner Thom Mayne. 

The complex will consist of three interconnected buildings for 4,600 employees on 65,000 square metres of gross leasable land or a net 57,000 square metres. The complex will include a cafeteria, a conference centre and a public exhibition space. Each of the three buildings will be connected to one another by so-called sky-bridges. The Icon Tower will be the tallest at 11 floors and will have space for 1,300 employees. The Landmark Tower will instead be the largest, covering 23,700 square metres on nine floors. The Skygarden Tower at the centre of the complex will house a conference centre. Some 310 people are at work on the project, with their number expected to rise eventually to about 400.

The project will apply standards of energy efficiency and environmental sustainability to meet Gold Leadership in Energy and Environmental Design (LEED), one of the most popular green building certification programs in the world 

Three interconnected towers for the new HQs

The New Eni HQs is composed of three buildings, each with an independent entrance halls:

• Icon Tower: it's the tallest building with 10 floors above ground. It holds the HQ canteen of approximately 5.600 m2, which will seat approximately 1,100 employees.
• Landmark Tower: it's the largest building of the three, with an area of approximately 23,700 m2 on 8 floors.
• Skygarden Tower: it is the central building with 9 floors above ground. It holds the congress center with 360 seats, a cafeteria (with independent canteen), a catering area and a meeting area. Its top part hosts a panoramic garden with pedestrian walks and evergreen plants.
   

Finally, on the unique basement level for all buildings is a parking lot that can accommodate about 900 vehicles (cars, motorcycles, and bicycles).

Project challenges: Transfer Bridges

The most complex project challenges are those faced to build the bridges and the transfer structures between the buildings, bolted metal carpentry whose main membranes were partially assembled and then raised.

The Icon and Landmark buildings are connected to each other at the seventh-floor level by an 85-m spanning steelwork bridge. The width of the bridge varies from about 15 m to 3 m, as does its height: it starts at 20 m at the Icon, aligning with its deck, and reaches 6 m in height once it reaches the Landmark.

The bridge is built using two large Warren-type reticular beams (without uprights), connected to each other at the level of the seventh floor and on the roof with floor reticular beams braced with Sant'Andrea cross profiles. The bridge transfers the vertical loads at the Icon to suitably tapered reinforced concrete pillars to allow support and onto reinforced concrete partitions on the Landmark.

The connection between the Icon and Skygarden buildings is made through a carpentry metal bridge, approximately 68 m long, which is level at the second level. The bridge consists of three spans: two with about 15 m clear span and one with 38 m span; it has a constant width of 3.30 m and height of 6 m.

The bridge structure consists of a 1.60-meter-high box girder made of welded plates of thicknesses ranging from 8 to 24 mm. Appropriate stiffeners are provided at the supports. The walking surface is made of a 15-cm-thick reinforced concrete slab cast on 5-cm-thick precast reinforced concrete formwork slabs. At the ends of the bridge are joints that make its structure independent of that of the Icon and Skygarden.

Sustainability and improved energy performance

The building produces energy, independently, through its solar panels

The New Eni HQs was developed in compliance with the stringent standards of energy efficiency and environmental sustainability with interventions, design and plant choices that determine the efficiency and low environmental impact of the complex.

The design of the new Eni HQ since its conception has pursued LEED (Leadership in Energy and Environmental Design) environmental sustainability certification with final goal level Gold. With regard to the energy and atmosphere side, the systems serving the building are of the low-enthalpy type (radiant ceiling panels), with high-efficiency production of the air-conditioning fluids. The entire building has a high-performance covering, with low solar factor and low thermal transmittance values.

All the iron and concrete are provided from locations that are less than 200 km distant from the construction site, containing recycled quantities greater than 90% (iron) and more than 5% of the concrete. All paint, varnishes, coatings, fitted carpets are with low VOC emission.

In building the New Eni Management HQ, all the indications of the Level(s) framework, the European level for the design and construction of sustainable buildings (intended for office or residential use) based on the entire life cycle of the building, were also respected.

The façade design is inspired by the geological formation of the Earth, visible in the optical effect adopted for the micro-perforated metal sheet exterior cladding and the stratified shapes of the buildings that seem to emerge from the site.

The new complex meets the goal of ensuring better performance with regard to energy and the natural lighting of the environments, through a double-skin system extended to all building façades, with the sole exception of the ground floor. Here, a Clear Glass that covers the total building height, and to the headers, which have a variable slope in the vertical and horizontal planes, where there is a Dark Grey façade obtained with colored paste or coated glass.

Each type features the same system of continuous façade with double-glazed class sealed to the cell's frame with SSGS structural silicon (Structural Sealant Glazing System), which in turn supports the external shielding system with different configurations:

• The "Orange" façade is made of a covering with drilled metal panels (55%) with different inclinations and organized in panels.
• The "Blue" façade is made with a combination of different types of panels made with horizontal drilled thin metal sheets (55% drilled), of different dimensions and inclinations.