The Eden Project, a £57m showcase for global bio-diversity, is one of the most innovative and high profile Millennium Projects. It is the largest plant enclosure in the world built in the lightest and most ecological way possible.
The project consists of three principal structural elements brought together in a 15-hectare landscaped site, formerly a worked out Cornish clay-pit. These elements are the ‘biomes’, a sequence of eight inter-linked transparent domes that encapsulate humid tropic and warm temperate regions, a biome link building and a hilltop Visitors Centre.
The biomes represent the perfect fulfillment of Buckminster Fuller’s vision of the maximum enclosed volume within the minimal surface area.
Working in steel means that the size of the module can be kept as small as possible, allowing for rapid and low-maintenance erection. Durability of the structure is ensured by the method of steel protection.
The biomes are an exercise in efficiency, both of space and of material. Structurally, each of the eight interlinking domes is a hex-tri-hex space frame. This frame comprises two layers: an icosahedral geodesical made up of hexagonal steel modules and a secondary web of hexagons, pentagons and triangles.
The structure is so lightly engineered that the steel is the minimal thickness (2.9 mm wall) needed to achieve the maximum coating potential in terms of steel protection.
Wherever possible, due to the immense size of the project, high level maintenance access is avoided, with all mechanical and electrical equipment (except the vent opening mechanisms) situated at ground level.
The “skin” comprising triple-layered ETFE (ethylene tetra floura ethylene) pillows that vary in diameter from 5m to 11m, is smooth enough for dirt to be washed away by the rain, thus avoiding the need for cleaning.
The pillows provide the same degree of insulation as double-glazing, but are only 1% of the weight. Their size and highlight transmission ensure that the maximum amount of daylight can filter through the plant life beneath.
In this way, the form of the building is directly related to its function: a tangible expression of the client’s aim to draw global attention to human dependence upon plants.
Images © Peter Cook
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