Never before have huge structures on the scale of the Galets been constructed of plastic membranes, metal rings and air. Anyone with ambitions to imitate these UFO-like objects on the platform of the Arteplage Neuchâtel will do well to read the following instructions carefully!
As a rule, the building kit for an Expo.02 Galet (pebble) consists of a few lengths of plastic, an outsized oval metal ring, several columns to bear the whole construction at a height of 20.00 metres, and a ventilator to inflate it. In order to ensure that the different elements are correctly assembled, around thirty architects and planners from Switzerland, Germany and Italy are needed for the planning, as well as about sixty workmen for the actual construction stage.
Weld the 15.00 x 2.50-metre lengths of plastic into two large tarpaulins and hang them one over the other in the metal ring. Now fill them with air and observe how the membranes gradually assume the shape of a huge balloon.
In order to stabilise this wobbly construction, the air pressure inside must remain constant. This is achieved by placing a ventilator inside the envelope. The number of revolutions per minute required to maintain normal air pressure is relatively low. It is, however, advisable to install a stand-by power-generating unit to ensure that there is no interruption in the ventilator's function, since this would result in the envelope running short of air. If snow collects on the Galets in winter, this can be melted by heating the stream of air. The Galets are assembled at a height of 18.00, 20.00 and 22.00 metres. They serve Expo.02 as a roof for the exhibitions on the Neuchâtel platform. The structure is not borne by the platform itself but is anchored in the lake bed by metal columns. A hydraulic installation raises the galets to the desired position during the final phase of construction.
60.00 to 105.00 metres in diameter
The maximum diameter of the smallest Galet is 60.00 metres, that of the largest an impressive 105.00 metres. The three constructions cover an area of 3'500, 4'000 and 9'000 square metres. The whole platform covers an area of 27'000 square metres, equivalent to that of four football grounds. So make sure that you have enough space at your disposal before assembling the Galets - even if you are not working with the same dimensions as Expo.02.
The Neuchâtel Galets are the largest structures of this kind ever to be constructed. Their construction was made possible by use of computers for the complex calculations, as well as for the constant supervision of the unconventional structures during operation.
Incidentally, the Neuchâtel Galets are looking for a purchaser when Expo.02 is over - perhaps someone for whom these building instructions are insufficiently detailed to enable to build their own galet? If the Galets do not find a buyer, they will be dismantled and the elements of the building kit recycled.
Photos: © Michel Jaussi www.jaussi.com