The project calls for building half of the functional programme above ground, the other half underground. Instead of building an underground programmatic plate, we propose a negative urban space, a small piece of underground city, carved and modulated on the urban warp characteristic of Sicilian cities, from Palermo to Avola, but built from top to bottom.
Place Palermo, Italy
Program Administration offices, Housing, Schools, Archives, Library, Exhibition, Auditorium, Retail and Restaurant, Sport, Multimodal Hub
Client Regione Sicilia
Budget 270mio €
Lead Architect, Coordination XDGA (Xaveer De Geyter Architects)
Xaveer De Geyter, Federico Pedrini, Doug Allard, Elena Caruso, Anne-Sophie Rouillere, Catherine Cornu, Johan Cool, Menelik Jobert, Nathalie Devoghelaere, Philip Niekamp
Landscape XDGA – Federico Pedrini, Doug Allard, Elena Caruso, Nathalie Devoghelaere, Anne-Sophie Rouillere, Johan Cool
Structures MJW Massimo Majowiecki, Giovanni Berti, Davide Carreri
MEP + Local Architects Mate Engineering, Tommaso Cesaro, Michela Pucciarello,
Traffic and Mobility TRT, Fabio Torta, Tito Stefanelli
Sustainability (subconsultant) Transsolar, Nadir Abdessemed, Clara Bondi
The excavation corresponds to about four floors. These inverted buildings are then separated and organised on an orthogonal grid oriented NW SE, all gathered around a large tree-lined public space, square in shape and placed in the centre.
The large garden square, an oasis of eighty-one metres on each side, acts as a point of convergence of all flows: the connection to the nearby railway station arrives here and the main entrances to the various functions, including the office reception, face here.
On the north side of the square stands the large volume that will house the new regional administrative headquarters, a forty-two-storey parallelepiped with a base of eighty-one metres by thirty-two and fifty-five metres high.
The volume is served by four central distribution cores that also function as bracing pillars. The result is a slender shape, elongated from east to west, which optimises solar exposure.
This crystalline monolith is interrupted by a large void at mid-height, which divides it into two sections to accommodate a raised belvedere terrace. Structurally, the upper part is suspended from the central cores.
The parallelepiped is thus broken down into a stereoscopic image which gives the building four distinct characters depending on the cardinal point of observation.
To the south a double skin composed of ten 8.1m wide vertical bands, every second of which is a veranda. The other facades are triple-glazed curtainwalls to maximise indirect daylight. To the north the bands are horizontal, one transparent and one in opaque enamelled glass. To the east and west the glazing has cladding.
The underground plinth has a sober appearance. The buildings consist of thick walls made of raw earth obtained by reusing excavated material produced on site.
Its thermal mass has a positive effect on the local microclimate and has the capacity to absorb and release moisture to improve interior comfort.
The green spaces are grouped into three landscapes. In addition to the series of verandas, terraces and winter gardens located at various heights in the complex, there is a large roof terrace directly accessible from the street, a series of patios grouped around a large central tree-lined patio and a large Belvedere terrace in the centre of the tower. The network of underground streets leads to the central Grand Patio, a large public open space, a garden square, characterised by the monumental foliage of domestic pines.
The Mediterranean Terrace at ground level is a large, verdant public plaza, contrasting with the large hypogeum garden for its sparser, typically Mediterranean vegetation.
Approximately halfway up the volume of the tower, at the fifteenth floor, is a triple-height panoramic terrace. This elevated garden houses a small cafeteria and drinks kiosk. A public lift, with controlled access, offers a panoramic view of the Conca d’Oro.