The cable membrane structure system
The cable membrane structure -- cable membrane structure - Oak Jinding master -21 century building is stable surface tension compression with high strength flexible film material is subjected to other materials and the formation of the space structure, can withstand a certain load. The modeling of free, lightweight, soft, full of a sense of strength, flame retardant, simple manufacture, quick installation, energy saving, safety, easy to use and other advantages, so that it is widely used in the world.
Membrane structure architecture as a new architectural form in the fifty century in the international began to appear, has a history of more than 40 years, especially after the seventy's, the application of membrane structures has been developing rapidly. Membrane structure provides a new choice other than traditional beyond architectural model for architects.
Membrane structure changed the traditional building materials and the use of membrane material, its weight is only 1/30 of traditional architecture. And membrane structure can overcome the traditional structure in large span fundamentally (no support) architecture implemented on the difficult, can create great shining visual space. The modeling of free light, flame retardant, simple manufacture, quick installation, energy saving, easy and safe to use and other advantages, so that it is widely used in the world. In addition, it is worth mentioning that, in the sunlight, inside the buildings by covering the full nature of diffuse light, distinguishes the strong contrast with smooth and shadow, indoor space visual environment open harmony. At night, the lights inside the building through the roof membrane lit up the night sky, the shape of the building shows fantastic effect. This structure is especially suitable for large stadiums, entrance corridor, sketch, the public square entertainment, exhibition, shopping malls and other fields.
Glass fiber membrane PVC. The membrane material development and application of earlier, usually specified in the PVC coating on the glass fiber fabric on the intersection line of thickness not less than 0.2mm, the general coating is not too thick, can meet the use requirements. In order to improve the anti-aging properties of PVC itself, often to add some light, heat stabilizer coating, light colored transparent products should be with a certain amount of UV absorber, dark products often with carbon black as a stabilizer. In addition, surface treatment on PVC there are a lot of methods, metal films can be used in PVC are laminated with a layer of thin or sprayed aluminum fog, using mica or quartz to prevent surface sticky and contamination. Fiberglass silicone resin of architectural membrane materials. Silicone resin has high and low temperature resistance, excellent water repellent, antioxidant characteristics, the film material with high tensile strength and modulus, it also has good light transmittance. Vestar membrane materials the United States Owens Cornyn company development is made of this resin for coated glass fiber cloth, at present this kind of membrane material application is not much, the manufacturer is also less. Glass fiber synthetic rubber membrane material for building. Synthetic rubber (such as nitrile rubber, chloroprene rubber) good toughness, the aging stability of sunshine, ozone, heat, and has outstanding abrasion resistance, chemical resistance and flame retardancy, can achieve a translucent, but because of easy to yellow, it is generally used for dark coating. Expanded PTFE architectural membrane materials. Affixed cloth sides by expanded PTFE woven fabric fluorine resin film which was puffing membrane PTFE. Because of its cost is too high, the general construction considering two aspects of cost and performance, rarely choose this membrane, there are not much foreign manufacturers.
ETFE architectural membrane materials. By the ETFE (ethylene tetrafluoroethylene copolymer) raw material directly into the. ETFE not only has the good Foshan Nanhai Luo Village Cultural Square anti impact properties, electrical properties, thermal stability and chemical resistance, and high mechanical strength, good processing performance. In recent years, the application of ETFE membrane material can replace other products showed a strong advantage and market prospect in many ways. Material transparency this film is particularly good, known as "soft glass, light weight, only the same size glass 1%; good toughness, high tensile strength, not easy to be torn, ductility than 400%; weathering resistance and chemical corrosion resistance, high melting temperature can reach 200 DEG C; effective use of natural light. Energy saving; good acoustic performance. Self cleaning function so that the surface is not easy to stain, a small amount of rain washed away dirt and can be stained, cleaning cycle of about 5 years. In addition, ETFE film can be into a thin film of bubbles in the prefabricated off, convenient construction and maintenance. ETFE also has disadvantages, such as the external environment is easy to damage the material resulting in leakage, maintenance cost is higher, but with the construction of large gymnasium, tourist sites, lounge, ETFE highlights the advantages of their own. The current production of the film material companies rarely, only ASAHIGLAS (AGC), Asahi, Germany Cowell a few companies can provide ETFE membrane material, development and application of this kind of membrane material in developed countries but also in more than 10 years of history. The just completed Beijing Olympic Stadium "bird's nest" and "Water Cube" membrane structures by ETFE membrane materials, is currently the largest ETFE membrane structure, membrane materials imported products. The "bird's nest" by double membrane structure, using ETFE rain snow UV outer layer, inner layer with PTFE achieve heat preservation, anti condensation, sound and light effects of objective. "Double ETFE inflatable membrane structures using the water cube", a total of 1437 pieces of the air pillow, each piece as a "bubble", air pillow can control the amount of inflation, the shading degree and transparency of regulation, effective use of natural light, saving energy, and has good thermal insulation, eliminate echo, for athletes and spectators to provide a warm, comfortable environment. At present, the domestic film structure development is encouraging, with some large gym, lounge construction as well as the 2010 Shanghai World Expo and Guangzhou Asian Games and other international event held brought opportunities and challenges to the development of membrane structures in china. Especially in the membrane, China started late, low level of technology, most of the film material is still mainly rely on imports. PTFE, PVC and surface modified PVC and ETFE membrane material is the mainstream market, application of more extensive. Independent intellectual property rights of the existing PTFE membrane materials of our country, the performance also basically reached similar foreign product requirements. Many companies, research institutes and universities have conducted research on PVC surface coating materials, such as PVDF, of nanosized TiO2 paint etc. has achieved initial success, also in the surface self-cleaning treatment studies such as bionic lotus leaf structure of micro rough surface also started the. In the introduction of the world first-class production equipment and technology at the same time, speed up digestion absorption and innovation, the development of membrane surface treatment technology is suitable for the market demand of our country as soon as possible, to enhance our entire industrial textile product quality and market competitiveness has important significance.
Tensioned membrane structure (Tesioned Membrane Structure), is dependent on the tensile stress of the membrane itself with the support bar and cable membrane structure - Oak Jinding master cable constitute institution system. Exposure in the sun, inside the buildings by covering with a natural distinction between diffuse light, no strong contrast with smooth and shadow, indoor space visual environment open harmony. Night, building light through the roof of the film to light up the night sky, the shape of the building shows fantastic effect. Tensioned membrane structure is especially suitable for used to build the city landmark building roof, such as sports and entertainment venues, needs to have the effect of advertising shopping malls, restaurants etc.. City traffic hub is the key of building city lifeline, the use of functional requirements of each composition unit building clear sign. Therefore, in recent years, this kind of building more and more with the membrane structure. Architectural membrane materials for more than 25 years service life. During use, maintain mechanical form stable material constant can both in the snow or wind loads. Built in 1973 USA California La Verne university student activity center is tensioned membrane structure building has been 23 years of history. The testing and tracking of material loading and accelerate climate change experiments, it proved the membrane material mechanical performance and chemical stability index fell 20% to 30%, but still can use normally. The surface layer of the membrane is smooth, elastic, particles of dust, atmospheric chemical substances is extremely difficult to attachment and penetration, the erosion of architectural membrane rainwater can be restored to its original clean surface layer and the transparent.
Tensegrity structure (Tensegrity) is composed of a set of continuous rod and continuous or discontinuous pressure bar is formed by the combination of self stress, self support mesh frame structure, in which the "discontinuous pressure bar" is the meaning of the end part of the pressure lever do not touch each other, i.e., a node only connected with a pressure rod. Tensegrity is a structure of thought America architect R.B.Fuller first proposed, he thought the operation of the universe is carried out in accordance with the principles of tensegrity, namely gravitation is a balanced tension net, each planet is the network in an isolated point. Cable net in this structural system is equivalent to the gravitation in the universe, the compression bar independent corresponds to the planet in the universe.
The conceptual design of tensioned membrane structure
Only the correct expression of structural logic buildings have a strong persuasive power and expressiveness "this sentence reveals the essence of tensioned membrane structure. For the membrane structure, any additional support and modification are redundant, the structure itself is not consistent with the other; in other words, the configuration is not possible, because that kind of film is not flowing is the lack of stability. Tensioned membrane structure beauty lies in the perfect combination of the "force" and "shape". The basic composition unit of tensioned membrane structures usually have: membrane materials, cable and supporting structure (mast, arch or other rigid component).
Membrane material is a new building materials, has been recognized as the sixth building materials after the brick, stone, concrete, steel and wood "". The membrane material itself cannot compression cannot bend, so to make membrane structure normal work must introduce appropriate pre tension. In addition, another important condition to guarantee the normal work of the membrane structure is to form reciprocal surface. The traditional structure in order to reduce the deformation of the structure is necessary to increase the resistance of a structure; and the membrane structure is by changing the shape to disperse the load, so as to obtain the minimal growth. When the membrane structure deformation in the neighborhood of the equilibrium position, can produce two kinds of restoring force: one is caused by geometric distortion; another is caused by the material strain. Usually geometric stiffness elastic stiffness than much, so to make every film has good stiffness, should as far as possible the formation of negative Gauss curvature, namely respectively along the diagonal direction form of "high" and "low". "High" is usually provided by the mast, perhaps is because of this reason, some literature also put the tensioned membrane structure called the hanging membrane structure (suspension membrane). Cable elastic boundary as the membrane material, divided into a series of membrane material diaphragm, thereby reducing the free support length of the membrane material, the more likely to form a larger curvature thin film surface. Literature suggests, free support length should not be more than 15 meters of the membrane material, and monolithic membrane coverage area is unfavorable more than 500 square meters. In addition, another important role of cable is to provide additional support to the mast and other supporting structure, ensuring not caused the collapse of the supporting structure for the breakage of the membrane material.
Membrane structure design mainly includes the following contents:
1, the initial state analysis: ensure that generate shape stability, stress distribution of 3D surface evenly balanced, and can resist all possible load condition; it is a revisionist process. 2, the self weight load state analysis: the membrane structure is very light, only 1 / 5 to 1 / 40 of steel structure, concrete structure; therefore, the membrane structure has a good adaptability to the seismic force, and the action of wind sensitive. In addition to consider snow load and live load. Due to the current observation data is less, so the design of membrane structure is usually adopted the method of coefficient of safety.
3, main structural components to determine the size, and the finite element analysis of supporting structure. When the design method of the support structure and membrane structure is at the same time, should pay attention to the conversion coefficient between different design methods.
4, connection design: including the size of bolts, welds and secondary component.
5, tailoring the design: this process should provide necessary test data, including young's modulus of the selected membrane material and cut compensation value (determined by biaxial tensile test). Membrane structure need to consider the issue in the plan stage:
1, the size of the pre tension and tension mode;
2, according to the control load to determine the size of the diaphragm and cable layout;
3, considering the membrane surface and the shape of the fixed device to avoid seeper (snow);
4, the design of key nodes, in order to avoid stress concentration;
5, considering the membrane transport and hoisting;
6, durability and fire.
Points to consider in the design of membrane structure stage of:
1, ensure the membrane surface is enough to obtain curvature, large stiffness and aesthetic effect;
2, the refinement of supporting structure, in order to fully express the transparent space and light shape;
3, to simplify the connection node between the membrane and the supporting structure, reduce the amount of construction site.
The main problem of the membrane structure:
1, the form finding (Form-finding) or further called "form theory";
2, considering the structural response of membrane materials and anisotropic under relaxation;
3, the dynamic stability of structure under wind load;
The 4, cutting optimization;
5, membrane interaction between cable and supporting structure.
The development direction of the membrane structure and membrane structure is a structure form in the latest development, it takes the excellent properties of fabrics as the material, or is inflated into the membrane, by air pressure supporting membrane surface, or by flexible cables or rigid support structure will face taut, thereby forming a structural system with a certain stiffness, able to cover a large span space. Since the 1970's, the membrane structure in foreign countries have been gradually applied in sports buildings, shopping malls, exhibition center, traffic service facilities such as large-span buildings. Membrane structure has become a major design scheme selection in the structure. Has become an important field of chemical fiber and textile applications. In recent years in the Chinese building structures have also made great progress. USA Pavilion Expo Osaka is used in gas bearing type air membrane structure. The quasi elliptic, axial size is 140m * 83.5m exhibition hall is the first film structure of large span in the world, and is used for the first time in polyvinyl chloride (PVC) coated glass fiber fabric. As a real modern engineering structures, the world exposition in Osaka exhibition hall marks the beginning of the era of membrane structure. Since then, membrane structure has been rapid development in the world. From the span, plane American Pontiac "silver dome" gas bearing type air film structure with 234.9m * 183m, began using polytetrafluoroethylene (PTFE) coated glass fiber fabric, a large gymnasium similar in North America built nine seat. In terms of area, suspended membrane structure of Saudi Arabia Chittagong airport departure hall covers an area of 420000 m2. As a new form of the membrane structure, cable dome in 1988 was first used in the Seoul Olympic Games gymnastics and fencing hall, then in some sports architecture popularized. Millennium Dome with its unique membrane structure, display the current level of development of construction technology and materials science.
Currently there are many manufacturers can produce PVC coated polyester fabric, but its performance is still not fully meet the requirements of fabric construction, as permanent materials for building needs to be further improved. It is reported that recently some companies are trial with PVDF surface layer of polyester fabric and PTFE glass fiber fabric, appearance and performance are greatly improved. Recently, foreign media show a hitherto unknown to the attention of China architectural design. In December 23, 2005 American "business week" selected Chinese ten new architectural wonders, including the Beijing Olympic main stadium, the National Swimming Center, Beijing Capital International Airport, Shanghai world financial center, the National Grand Theater, CCTV, Shanghai Chong Mingdong beach eco city, contemporary MOMA, Commune by the Great Wall, the East China Sea Bridge (Shanghai). The Beijing is located in the building have as many as seven. "Chinese is gradually become the most with the architectural and engineering design and creative stage." The development of the cause of building China, is to create a stage for today's top architecture and technology. The report firstly analyzes the economic reasons of new buildings China rise and the external environment. The article said, when the global attention of Beijing 2008 Olympic Games, not only is the world's fastest and most powerful athletes is to strive for the highest honor and intensify their efforts, a new generation of innovative building is Beijing land after another. Due to the strong support of be on the upgrade of the economy, the world's largest aviation port, energy saving and environmental protection building and the world's tallest outdoor sightseeing Taiwan will soon settle down Chinese one one.
This paper lists the appraisal result says, before 2008, the completion of the National Swimming Center (Water Cube), the National Stadium (Bird's Nest), the National Theatre China public are very familiar with the well-known venues more behoove into the "big ten" list. From the introduction and evaluation on them can be seen in the selection of the pursuit of environmental protection, natural esteem. For example, known as the "Water Cube" in the National Swimming Center, is energy-saving and environment-friendly building. The pool of water will be heated by solar energy, and then use a double filtering device can realize the water pool, and even the excess rainwater will be collected and stored in the underground pool. The complex engineering system and curved steel structure makes the external structure like a bubble, this unique structure design makes the "Water Cube" almost withstand any earthquake. This paper introduces the "bird's nest" wrote, to make the Beijing Olympic Games main venue of the 91000 seat, may be environment-friendly stadium has the largest gain of natural ventilation, the architect drew inspiration from nature, created an incomplete seal, but also can keep out wind and rain for athletes and spectators to shell. The stadium looks like a bird's nest made of woven branches; and the inner, from the lounge to the hotel, each a separate space is an independent unit, so that the natural air circulation become possible. The article points out, as the whole country's most popular color of the city, Beijing has attracted many famous architectural master career. Selected Beijing "Commune by the Great Wall," the works of contemporary architectural art is designed and built by 12 outstanding Asian architects. The design of Beijing "contemporary MOMA" to show that the new trend of environmental protection and new technology applied in residential and it represents the architectural development, sustainable development can be regarded as a model for large-scale residential building. It uses a ground source heat pump system is the largest in the world, will be used to help the connected by twentieth layers of Coffee Museum, dry cleaners and other series of service facilities in 8 buildings of the District, with most efficient way to keep the constant temperature and humidity, which is a major highlight of the building. Residential unit is also a major bright spot, is can be recycled wastewater, the wastewater filtering kitchen and wash basin, toilet recycling.
Tensegrity structure (Tensegrity) is composed of a set of continuous rod and continuous or discontinuous pressure bar is formed by the combination of self stress, self support mesh frame structure, in which the "discontinuous pressure bar" is the meaning of the end part of the pressure lever do not touch each other, i.e., a node only connected with a pressure rod. Tensegrity is a structure of thought America architect R.B.Fuller first proposed, he thought the operation of the universe is carried out in accordance with the principles of tensegrity, namely gravitation is a balanced tension net, each planet is the network of an isolated point. Cable net in this structural system is equivalent to the gravitation in the universe, the compression bar independent equivalent to the planet in the universe in twentieth Century 60 years with the development of modern flexible building materials, architects from the tent of simple building structure with the oldest, constructed a magical form -- membrane structure. It can form a single surface, structure form surface of different construction, meet the architects on architecture and aesthetics highly unified requirements.
The flexible material with transparent and anti ultraviolet function, is applied widely in some outdoor architectural and environmental sketch. It is precisely because of this feature, lighting design at night make membrane structure with distinct environmental symbol characteristics. Beautiful shape of the membrane material, stainless steel parts and fasteners with compact design is reasonable, the surface treatment of steel support structure strict, create a beautiful form, membrane structure design reasonable, occupies the position of play a decisive role in building environment design in today's world of.
stadium stands and entertainment space in recent years, with the construction of the concept of space continuously improve the deepening and scientific means, "return to nature", "bath natural warm" is a modern building environment the mainstream of development. Indoor and outdoor sight has become increasingly blurred, there appeared many also are also outside, mutual penetration of the indefinite space, such as: hall decoration, patio, four seasons hall, botanical garden, park square, the viewing platform, stage, stadiums, sporting, cultural entertainment. Because the membranes of light permeability, daytime sunlight can form slow fire light through the membrane material, make the film covering space within the reach of natural effect and outdoor almost the same, so the membrane structure can create the space form is comparable with the natural environment.
The central area of a city, signs of pieces reflect a city's geographical features and folk customs, at the same time, is also a symbol of urban culture development degree. Landscape design requirements and has a wide range of readability, tastes, both extraordinary artistic value, but also can make the popular and mass close. Distinct personality and identity of membrane structure with its elegant shape, soft and with a power curve and large span and large space, applied to the urban design in sketch.
Green promenade, in recent years, in the densely populated cities, in the configuration of the surrounding residential area of green space and pedestrian. Residents can not in a vehicle under the influence, relaxed and happy to walk, the rest in the residential area near the middle of the street area, and feel very comfortable. In the green space in the structure of a membrane pieces or corridor, waterside pavilions, leisure umbrella, not only vividly to beautify the environment (like a vast oasis in the middle of the little white sail), and have a strong functional (people can rest for a moment during walking hours), but also increase the sense of space staggered.
