METALBAU FRUH.

The Great Glass House is the largest single-span glasshouse in the world and the focal point of the National Botanic Garden of Wales (AR April 2000), a new 230 hectare park in Carmarthenshire. central Wales. Designed by Foster and Partners, it is an oval glass dome -- 95m long and 55m wide -- which will house over 100 000 plants and 10 000 species, many of which are endangered.

The domed roof, elliptical in plan, is a spare, elegant structure, comprising a series of 24 tubular steel arches which spring from a concrete ring beam. The longest arch spans 54m and rises to 14m above the main floor. The arches vary in length to reflect the elliptical plan. The end of each arch is fitted with a solid stainless-steel sphere which sits in a socket fixed down to the ring beam. This joint allows rotation to accommodate movement due to thermal expansion of the arches. The roof is glazed with trapezoidal 4 x 1.5m single-glazed panels of 16.8mm PVB laminated glass, silicone bonded to a silver anodized aluminium sub-frame.