The retaining walls of the B3-2 pavilion designed by the Archea firm for the Urban Best Practice area at the World Expo of Shanghai of 2010 appear as a shell inspired both by the outward-turned spatialism introduced in the Sixties and Seventies by leading figures in Italian art, and by the more recent Op Art experiences that we may appreciate in artists as Enrico Castellani. The apparently soft shell features a rigid overall geometry, and is essentially concretized in mechanisms aimed at diffusing daylight, something that also applies to the roof formed of a sequence of reflecting surfaces that diffuse the light from above.
The structural system:
The structure, which was assembled in as little as 9 months, is designed so that it may be disassembled and reassembled elsewhere thanks to the dry-assembly techniques adopted, which makes it possible to recover more than 90% of the parts.
This has been feasible thanks to the layered construction:
- A load-bearing structure in steel; the ashlars of the reticular beams have been prepared in the factory and then connected to the columns on site during the first three months of construction. The system consists of 16 tubular pillars with a rectangular section of 800×550 mm or circular ones with a diameter of 550 mm, installed on plinths supported by piles (nr. 7 in the figure).
- A secondary structure of steel pylons placed at intervals of 1515 mm, fastened onto the foundation beam in reinforced concrete and to the intermediate façade beams placed at a height of 9.3 m. This serves both as support for the outer skin and for the inner walls (nr. 2 in the figure).
- A surface of drywall panels fastened internally to the secondary structure, perforated by a row of square windows of different sizes arranged obliquely with respect to the vertical (nr. 1 in the figure).
- A surface of insulating panels intended for industrial constructions, fixed to the outside of the secondary structure, that forms the true thermal and hygrometric barrier of the building (nr. 3 in the figure).
- Glazed frames (with double glazing to reduce thermal dispersion) have been installed in the appropriate positions; special panels have been superimposed on them to realize the openings on the façade (nr. 6 in the figure).
- The façade substructure has been fixed to the insulating panels; it consists of a trellis of uprights and crosspieces in extruded aluminium, installed at 45° and fit into brackets fixed by means of self-tapping screws directly onto the support structure (nr. 4 in the figure).
- The final layer of the façade consists of a covering of the aluminium frame formed of a fiberglass fabric kept in tension by special tightening cables inserted in the extruded tubular elements forming the frame. Special pieces have been realized for the corners and for the 4 highest points of the building, as well as for the windows of various dimensions and forms on the façade: squares, triangles, trapeziums and lozenges.
- The material, chosen on the basis of the necessary characteristics of eco-compatibility, consists of a silicon-coated fiberglass membrane that is highly resistant to traction, translucent and durable. About 810 panels, covering a total surface of 3070 m2, have been used.
- The panels have been produced and pre-assembled in Italy by Tensoforma Trading S.r.l. by means of a special assembly technique that makes it possible to control the pre-tension of the membrane and the consequent equilibrium of the panel system, and have then been transported by sea to Shanghai and assembled on site (nr. 5 in the figure).
- A series of RGB LED apparatuses (able to change colour on the basis of programmed scenic designs) are installed along the perimeter of the shell, and embedded in the floor of the outdoor square in such a way as to underscore every diagonal crossing of the structural web of the façade.
|Location||Shanghai - China|
|Purchaser||World Expo Shanghai 2010 Holding Company|
|Structure||Favero & Milan Ingegneria - Tensoforma Trading S.r.l.|
|Building Surface||3070 sq. m|