JEC COMPOSITES MAGAZINE - Issue #33 - June 2007 - 44

44 he temporary hangar, which also serves as a place of maintenance for the aircraft, is covered by two Ferrari membranes: Précontraint® 1352 for the roof, and Précontraint® 1002 for the walls and the three motor-operated sliding doors. These extra-large (3 m x 21 m x 7 m) fabriccovered doors are lightweight and easily handled, but just designing and making them was a tough proposition. The doors are located on the building’s 68-metre-long facade and remain open most of the time so, with winds up to 184 km/h on the peninsula, the hangar is subject to wind suction loads of 159 daN/m2. This made for a very serious uplift problem. Natural light reaches all parts of the building. T Helicopter hangar with metal-fabric composite structure At the Lanvéoc-Poulmic naval air base on the Crozon peninsula in Brittany, France, Super-Frelon and Lynx aircraft are being housed in a 3,150-square-metre metalfabric structure made by the Toile et Structures Company, pending a permanent hangar structure that is scheduled to be ready by 2009. A real challenge FEATURE “Construction” The challenge facing the Toile et Structures Company was to adhere to a solution involving three-dimensional, variablegeometry arches with lower chords made of cables and diagonal cables between the tubular spreaders*. The result is a lightweight structure with savings on materials, simplified assembly (clevis and pins only), transportability, and ease of fabrication and installation. “Thanks to this solution, we were able to deliver a building 3,150 m2 in area and 12 metres high that weighed only about JEC Composites Magazine / No33 June 2007 24 kg/m2 (including the walls), or as much as a standard roof without the framework!” declared Dominck Owen-Jones, head of the Textile Architecture department at Toile et Structures. Innovation has been a focus in this project, especially concerning the fasteners for the textile composite membrane. The use of bolt ropes exterior to the sleeves made it possible to deliver the membrane on spools. In this way it could be gradually unrolled for installation and kept out of the wind insofar as possible. Another distinctive feature is the building’s anticlastic (saddle-shaped) roof, with stability guaranteed by the membrane’s tension state (pretension: 200 daN per linear metre). Natural light reaches all parts of the building, so technicians can carry out their daily tasks in good lighting conditions. Because it will eventually be dismantled, the translucent textile structure was designed to be transportable for reassembly at another site. Table: Technical specifications of the textile membranes Précontraint® 1002 Précontraint® 1352 Yarn Total weight Width Tensile strength Tear strength (warp/weft) Adhesion Fire rating Treatment Quality assurance 1,100 Dtex PES HT 1,050 g/m2 180 cm 420/400 daN/5cm 55/50 daN 12 daN/ 5 cm M2 1,100/2,200 Dtex PES HT 2,000 g/m2 180 cm 800/700 daN/5cm 11/13 daN 13 daN/ 5 cm M2 Standards NF EN ISO 2286-2 NF EN ISO 1421 DIN 53.363 NFG 37.107 NFP 92.503 surface lacquer with PVDF alloy for improved dirt resistance ISO 9001 ISO 9001
JEC COMPOSITES MAGAZINE - Issue #33 - June 2007

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #33 - June 2007
