Membrane Structures and Membrane Materials

Membrane Structures and Membrane Materials 2008年北京奥运会国家游泳中心水立方方案英国格林威治千年穹顶（Millennium Dome）

Content • Membrane Structures • concepts and features • development • applied fields • structures • Membrane Materials • structures • properties • Examples

Membrane Structures • Prestressing force can be produced by high strength membrane material, reinforced component (steel frame, steel column, steel cable) • To form some space shape as cover structures bearing outer load

Structure features • various shapes • light weight • good earthquake resistance • large span • natural light • energy efficient • self-purification • fast construction 1985年日本茨城县国际科学技术博览会拱形大门美国南加州大学La Verne分校的学生活动中心加州旧金山国际展览大厦“蝴蝶”

Development • In ancient times, hide wigwam • In the 1950s, German scholar FreiOtta • Soap Membrane Principle － any point on soap has the same tensile stress on any line • Membrane Structure Analysis－Minimum stress curved surface • In 1957，Cologne Federation Curtilage fair,louvered awning composite PVC • In the 1970s, PTFE (polytetrafluoroethylene, trade name Teflon) • In 1973, the earliest PTFE membrane engineering • At present, new development by computer technology and three-dimensional shape design.

青岛馥香谷会所 Membrane Structures • culture—exhibition center, theater, museum • gymnasium—gymnasium, natatorium • commerce —plaza, hotel, commerce street • traffic —airport, railway station, toll station,dock • industry —factory, greenhouse, logistic center • tourism —entrance of architecture, paragon, park 日本熊本市公园

Membrane Materials • basis metal basketwork－deciding strength and elasticity • PA polyamide • polyester fibre • glass fibre • aromatic polyamide fibre • coating － functions:fire prevention, waterproofing, ultraviolet protective property • organic silicon resin • polyurethane • butyl rubber、CR chloroprene rubber • PVC • PolytetrafluoroethyleneTPFE

Weave of Membrane Material Dense interleaving weave High tensile strength Thin interleaving weave, high adhesive force,good tear resistance Flat weave, thin,good tear resistance

Fire Prevention Property • A －non-burning glass fibre/TPFE composite material • glass fibre >150g／m2 • coating 400—1100 g／m2 • thickness of membrane material >0.5mm • B－burning but not all, glass fibre/PVC, glass fibre/CSM composite material • fire prevention • others same with A • C－burning but not spreading, polyamide/PVC polyester /CR • glass fibre >100g／m2 • coating 400—1100 g／m2 • thickness of membrane material >0.5mm • Grade 2 of Fire-resistance

Strength Property • tensile test-biaxial tensile test • Pretension will enforce load resistance ability • 0.7－1.2mm membrane 200－600kP／5cm • strength decreases with air pressure

Sound absorption property • Inner membrane has good performance in elasticity, air permeability and absorbing sound weave • double deck membranes will increase sound acoustics in the inner space dramatically • Good reflection in 500-2000 HZ tone frequency

Incubation and Energy Saving Property Group 1：traditional roof Group 2：polyester long fibre membrane material Group 3：PTFE glass fiber Group 4：SILICON membrane Group 5：PTFE glass fiber membrane and 250 M/M air layer Group 6：PTFE glass fiber membrane pluslight permeability heat insulation membrane

Light Permeability Light Permeability：3-20% inner membrane is 0.4mm so light has good permeability. Inner membrane does not affect the total light effect in double deck membrane.

Gasing－Air-supported membrane architecture • first patent in Britain， Lanchester in 1917 • blasting system • curving membrane area • interleaving cable • ground beam, wall beam • good lucency • for less snow area • over 250m span for lower cost 日本东京室内棒球馆

Stretching 深圳华侨城欢乐谷中心剧场张拉式索膜结构大连金石滩影视艺术中心青岛颐中体育场我国第一个自行设计和安装、整体张拉式索膜结构体育场北京郡王府广场

伯戴尔膜工程公司的入口雨篷 Stretching－hyperboloidalparaboloid • saddle-backed cell • quadrate or arrismembrane fabric • side cable set around the membrane • distance between diagonally dots are set in design • stretching by 4 angles to find space form and structure of hyperboloidalparaboloideasy to form close space

Stretching－wimble hanging chain • tent membrane cell • flying rings supported by knighthead • membrane embedded in rings • fixed sides • for multi-peak membrane architecture 美国加州某教堂

Dome structure • Elliptoidedged pressing rigid ring beam • Triangle grid strain system • loop successive cable net • vertical pressing beam • embedded in ring beam • Membrane in cable net • Prestressed dome • Easy drainage on membrane grade 佐治亚穹顶

Mast cable-stayed structure • A coverage of 80,000 m2 • 12 hundred-meter masts on the circle of reinforced concrete ground beam • Top structure of mast • circle of diameter 364m supported by inner spread steel • out-spread steel in ground anchor • Dome • arc framework • (sector) PTFE • 50m central height 英国泰晤士河畔的千年穹顶

Problems in Water Cube • Arboretum in London, Britain • Thick leaf mold in ETFT and steel structure • In big membrane, wrinkles are formed for uneven pressure in two directions • huge investment of a billion • 2000 yuan per square meter every 0.2mm ETFT • Depreciation up to 20－30 million per year • Layout “水立方”与“鸟巢”交相辉映

Membrane has great vitality through the development of new materials and technology • Most competitive architecture in the 21th century

Membrane Structures and Membrane Materials