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A Nissen hut is a prefabricated steel structure, made from a half-cylindrical skin of corrugated steel. Originally designed during World War I by engineer and inventor Major Peter Norman Nissen, it was used extensively during World War II. ==Description== A Nissen hut is made from a sheet of metal bent into half a cylinder and planted in the ground with its axis horizontal. The cross-section is not precisely semi-circular, as the bottom of the hut curves in slightly. The exterior is formed from curved corrugated steel sheets 10 feet 6 inches by 2 feet 2 inches (3.2 × 0.7 m), laid with a two-corrugation lap at the side and a 6 inch (15 cm) overlap at the ends. Three sheets cover the arc of the hut (about 54 sheets in all are required). These are attached to five 3 × 2 inch (7.5 x 5 cm) wooden purlins and 3 × 2 inch wooden spiking plates at the ends of the floor joists. The purlins are attached to eight T-shaped ribs (1¾ × 1¾ × ⅛ inch; 4.5 × 4.5 × 0.5 cm) set at 6 feet 0.5 inch (1.8 m) centres. Each rib consists of three sections bolted together using splice plates, and each end is bolted to the floor at the bearers. With each rib are two straining wires, one on each side, and a straining ratchet (or in some cases a simple fencing wire strainer). The wires are strained during construction. The straining wires do not appear in the original Nissen patent. The purlins are attached to the ribs using a "hook" bolt, which hooks through a pre-drilled hole in the rib and is secured into the purlin. The hook bolt is a unique feature of the Nissen design. Interior lining could be horizontal corrugated iron or material like Masonite attached to the ribs. Sometimes corrugated asbestos cement sheeting is used.〔(【引用サイトリンク】url=http://archaeologydataservice.ac.uk/catalogue/adsdata/arch-1045-1/dissemination/pdf/ )〕 The roof and lining form a circular space with a radius of 8 feet 0.5 inch (2.4 m), although, because of the inward curve, the floor is only 15 feet 10 inches (4.8 m). The space between the interior and exterior lining may be used for insulation and services, if required. The walls and floors rest on foundations consisting of 4 × 4 inch (10 × 10 cm) stumps with 15 × 9 inch (38 × 23 cm) sole plates. On these are 4 × 3 inch (10 × 8 cm) bearers and 4 × 2 inch (10 × 5 cm) joists at 2 feet 10 inch (86 cm) centres. The floor is made from tongue and groove floorboards. At East Hills and at Villawood the floor is concrete; the ribs in this case were simply attached to the concrete slab by a metal strap. At either end the walls are made from a wooden frame with weatherboards nailed to the outside. Windows and doors may be added to the sides by creating a dormer form by adding a frame to take the upper piece of corrugated iron and replacing the lower piece with a suitable frame for a door or window. Nissen huts come in three internal spans — 16 ft (4.9 m), 24 ft (7.3 m) or 30 ft (9.2 m). The longitudinal bays come in multiples of 6 ft (1.83 m). The corrugated steel half-circles used to build Nissen huts can be stored efficiently, because the curved sheets can be cupped one inside another. However, there is no standard model of Nissen huts, as the design was never static but changed according to demand.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nissen hut」の詳細全文を読む スポンサード リンク
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