To build the platform, the architects used a technique that is thousands of years old in the region: pile construction.
The forum, a huge platform measuring 26'791.20 m2 (183.00 m x 146.40 m), was an artificial island rising above the water level. 480 piles supported the forum, which was made up of a total of 90 flat elements (12.20 m x 24.40 m).
Piles
The piles of the platforms were used for the second time at the Expo - they came from district heating systems in the Czech Republic. Batigroup had bought them, made them available to Expo.02 and then fed them back into its own construction process. It had the dismantled district heating pipes welded together in Cornaux to form 480 piles 0.53 metres in diameter and 48.00 metres long and then driven 32.00 metres into the ground at the Arteplage site.
Steel girders
The manufacturer, Ferroflex in Rothrist, leased the HEB 300 girders to Batigroup for the duration of Expo.02 and put them on the market in 2003, three years late. To ensure that the girders remained intact, Batigroup had the two reinforcing bars per girder welded onto steel shoes for the under-tensioning and had these welded over the ends of the girders. The struts of the under-tensioning stood on the reinforcing bars and were attached to the girder with screw clamps. This meant that at the end of Expo.02, the sub-tensioning could be unscrewed and removed without damaging the girder.
Platform element
The load-bearing surface of the platform consisted of a board stack construction made of fir wood. 240 wooden beams per platform element (12.20 m x 24.40 m x 0.33 m) were screwed together in two layers, each offset in height. The EPF Lausanne developed this system, called Dalle O'Portune, and it supports lorries weighing 28 tonnes. Kerto panels, Scandinavian laminated veneer lumber, lined the wing. All the wooden joints were screwed together. These were loosened again after Expo.02 and the wood was subsequently used for farm infrastructure.
Arteplage
Neuchâtel
Concept
Concept Bois Technologie SA, St-Sulpice www.cbs-cbt.com
General contractor
Batigroup, Basel
Responsible Batigroup
Jean-Marc Allegri (project management)
Lucien Mulhaupt (project management)
Jean-Claude Rais (siteanagement)
François Prongué (site management)
Alex Pritz (site management)
Engineers
Guscetti & Tournier SA (deleted), Genève
Géotechnique Appliquée Deriaz SA, Genève
Dauner Ingénieurs Conseils Sàrl (cancelled), Aigle
Concept Bois Technologie SA, St-Sulpice www.cbs-cbt.com
Allemand Jeanneret Schmid (New: AJS ingénieurs civils SA), Neuchâtel www.ajs.ch
Environmental support
Prona AG, Biel-Bienne www.prona.ch
Construction site equipment Cornaux
Batigroup, Neuchâtel
Foundations
Keller Spezialtiefbau, Baden-Baden, Germany www.keller-spezialtiefbau.de
Hydraulic engineering
Schweizer Wasserbau AG, Aesch
Steel construction
Zwahlen Mayr SA, Aigle www.zwahlen.ch
Timber construction
Concept Bois Technologie SA, St-Sulpice www.cbs-cbt.com
Responsible Expo.02
Bernard Bourquin, Head of constructions
René Spahr, Head of Arteplage Neuchâtel
Photos: © Atelier Oï SA; © Erdjan Opan; © Philippe Rualt; © Archive Ralph Ammann; Expo.02 Presentation
