Eden Project hopes it will be one of the world's leading botanical gardens. When complete, it will display hot tropical and warm temperate plants in walk-through, apparently natural, eco-systems, within two huge hothouses made up of intersecting geodesic domes.
Covering 1.5ha, the larger hothouse will comprise seven geodesic domes. The smaller hothouse will have six intersecting domes.
Consultant Anthony Hunt is now checking the detailed design for the hothouses, produced by German specialist subcontractor Mero. Mero will erect a jumbo falsework system this month and start steel erection in September. Steelwork is expected to finish by February.
Anthony Hunt and architect Nicholas Grimshaw & Partners developed the concept for the hothouses' lightweight geodesic structure to meet demand from the project's horticulturists for column-free open space on a giant scale. The two hot houses, joined by a cedar shingle-clad and earth roofed 'link building' will cover 1.5ha and 0.7ha respectively, without internal support.
Cladding will be ultra-light triple-layered ethylene tetrafluoroethylene panels. ETFE is relatively light - a fraction the weight of glass - which means less structural steel is needed.
Though the domes are highly intricate in detail, Grimshaw project architect Jolyon Brewis describes the principle as 'simple and repetitive'.
Each one is composed of two grids connected by stiffening triangles. The inner grid comprises hexagonal and triangular cells, the outer grid is made up
of steel framed hexagonal cells. The ETFE cladding will be installed, pre-mounted in profiled aluminium frames in the hexagons of the outer grid.