|Short description of the project
||In 1992, on the occasion of an international exposition commemorating the 500th anniversary of the discovery of the Americas by Columbus, 5ha of commercial area on the old harbour of Genova and approximately 20000m² in old warehouses and other buildings in the area were used. The old harbor and the historical city district, which had long been seperated architecturally and physically, were rejoined through redevelopment, old 16th century buildings were restored, and an aquarium and the Bigo were newly reconstructed, the former on Spinola Wharf, providing a link between the past and the future. After the exposition ended, the facilities were turned into a large waterfront park and have since been administered by the city.
The Bigo is made up of eight masts and was inspired by a derrick on a cargo ship that used to be anchored in the harbor. It serves as a symbol of the exosition and supports an observation elevator, from which people can enjoy views of the harbor, the exposition grounds and the city. Embrico Wharf was covered by a tent roof and served as the exposition plaza. The roof of PTFE membrane and glass is suspended by cables from four steel tubular arches. Since the end of the exposition, this facility has served as a skating rink in winter and a place where miniature soccer gams for children or outdoor concerts are held in summer.
"The Winds of Columbus" , nine kinetic wind sculptures by Susumu Shingu, stand next to this tent. Made of 'tenara', a laminated PTFE fabric, these elegant sculptures respond to every breeze and change in the quality of light and evoke the wind that enabled Columbus to make his historic journey.
(Shunji Ishida, Renzo Piano Building Workshop)
Bigo is the old Genovese word for a ship's crane and so it is an appropriate name for this structure, which supports a membrane canopy 60m long by 40m wide covering part of the old harbor which is now transformed into a public piazza and performance place.
The "Bigo" consists of 2 independent sets of cigar-shaped booms forming out from a small island located within the water of the dock. One set of booms supports the membrane roof and the other carries a vertical cable-car passenger lift from the quayside. Both sets are anchored down with tie bars to foundations beneath the harbor water. Each boom is "cigar-shaped", an effect achieved by welding together a series of rolled conic plate section with an increasing taper towards the ends. The longest boom, supporting the cable car, is 70m long and the two directly supporting the membrane canopy are 48m long.
Radiating out from the tip of each of the booms supporting the canopy are fans of 16 cables which support slender arch ribs from which in turn the membrane canopy is suspended.
The canopy consists of 5 discrete membrane panels (made of PTFE coated glass fiber) each of which has cables edges. The connection of the membrane to the boundary cable uses a specially designed aluminium extrusion and cable clamps giving a good architectural appearance.
Glass lenses close off the gaps between the membranes. The glass is supported from spinetubes that span between the membrane suspension points. A pantograph mechanism automatically adjusts the position of the glass to follow that of the membrane roof under changing loads.
Because of the unusual form of the roof and its location within the harbor, wind pressure distributions were derived using statistical analysis of local wind data and a wind tunnel test.
Also adjacent to this roof are 9 wind-mobiles by the Japanese sculptor Shingu. These use flat triangular panels of woven PTFE cloth held within frameworks that are free to spin simultaneously about horizontal and vertical axes.
(Brian Forster, Ove Arup & Partners)
[Membrane Design and Structures in the World, Kazuo Ishii, p 92, 94]