Classification by support
Membrane structures are divided into flexible supporting structure system, rigid supporting structure system and mixed supporting structure system according to supporting conditions.
Classification by structure
Membrane structure can be divided into skeleton membrane structure, tension membrane structure and inflatable membrane structure.
Classification of membrane structure architectural forms;
Structurally, it can be divided into three forms: skeleton membrane structure, tension membrane structure and inflatable membrane structure.
1. Frame supporting structure
The roof skeleton made of steel structure or laminated timber adopts the structural form of tensioned membrane material, and the lower supporting structure has high stability. Because of the simple shape of the roof, the opening is not easily restricted and the economic benefit is high, it is widely used in any large or small space.
2. Tension suspension structure
It is composed of membrane material, steel cable and strut, and tension is introduced into the membrane material by the steel cable and strut to achieve stability. In addition to practicing creative, innovative and beautiful modeling, it is also the structural form that can best show the spirit of membrane structure. In long-span space, steel wire mesh composed of steel wires and compressed materials is often used to support the upper membrane material. Due to high construction precision, strong structural performance and rich expressive force, the cost is slightly higher than that of skeleton membrane structure.
3. Pneumatic membrane structure
The inflatable membrane structure is to fix the membrane material around the roof structure, and use the air supply system to raise the indoor air pressure to a certain pressure, so that the pressure difference between the inside and outside of the roof can resist the external force. Because the air pressure is used as the support and the steel cable is used as the auxiliary material, more space can be obtained without any beam or column support, so the construction speed is fast and the economic benefit is high, but the blower needs to be kept running for 24 hours, and the cost of continuous operation and machine maintenance is high.
Classification of membrane materials
Level a
Class a is the best, which is glass fiber fabric coated with PTFE (permanent membrane material);
Class b
Next is Class B, made of fiberglass fabric and covered with PVC.
Class c
Class C is the worst of the three, and it is made of PVC wrapped with polyester (polyester) fabric. According to the coating materials, there are polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polyvinyl chloride (PVC), polyurethane (PU), rubber and so on. Its service life varies with different surface coatings, generally reaching 12-50 years.
polytetrafluoroethylene
PTFE membrane is a material coated with PTFE resin on superfine glass fiber fabric. The film has good welding performance, excellent ultraviolet resistance, aging resistance and flame retardancy. In addition, its antifouling and self-cleaning performance is the best among all building membranes, but its flexibility is poor, its construction is difficult and its cost is amazing. Under the leadership of Geiger Company, Dupont Company, Corning Glass Fiber Company, Baird Construction Company and Chemical Fiber Weaving Company jointly developed permanent membrane materials. Its processing method is to quickly put the glass fiber fabric into the PTFE melt for many times, so that both sides of the fabric have uniform PTFE coatings, and the permanent PTFE film is formally born. Since then, permanent membrane structures have become popular in the United States, and many scholars have conducted in-depth research on membrane structures. The follow-up test results after 20 years show that the mechanical properties and chemical stability of this film material have only decreased by 20%~30%, and the color has hardly changed. The surface of the membrane is smooth and elastic, and dust and chemical particles in the atmosphere are extremely difficult to attach and penetrate. After being washed by rain, the building membrane can restore its original clean surface and light transmittance, which is enough to show the strong vitality and broad market prospects of PTFE membrane materials. The development and application of this membrane material in foreign countries are mature, and there are many manufacturers, such as Mehler Company in Germany, Verseidag Company, Taiyoko-gyo Company in Japan, Zhongxing Chemical Industry Co., Ltd., Chemfab Company in the United States, ObeiKan Company in Saudi Arabia, etc.
Glass fiber polyvinyl chloride
This membrane material was developed and applied earlier. Generally speaking, the thickness of PVC coating at the intersection of latitude and longitude of glass fiber fabric is not less than 0.2mm, and the general coating should not be too thick to meet the use requirements. In order to improve the aging resistance of PVC itself, some light and heat stabilizers are often added to coatings, a certain amount of ultraviolet absorber is added to light-colored transparent products, and carbon black is often added to dark-colored products as stabilizers. In addition, there are many methods for surface treatment of PVC, such as laminating a very thin metal film on PVC or spraying aluminum mist, using mica or preventing surface adhesion and pollution in time.
Glass fiber silicone resin
Silicone resin has excellent high and low temperature resistance, water repellency and oxidation resistance. The film has high tensile strength and elastic modulus, and also has good light transmittance. Vestar film developed by Owens-Knin Company in the United States is made of glass fiber cloth coated with this resin. This kind of membrane is not widely used and there are few manufacturers.
Glass fiber synthetic rubber
Synthetic rubber (such as nitrile rubber and neoprene rubber) has good toughness, stability to sunlight, ozone and thermal aging, outstanding wear resistance, chemical resistance and flame retardancy, and can reach a translucent state, but it is generally used for dark coatings because it is easy to yellow. Expanded polytetrafluoroethylene building membrane material. Expanded PTFE building film is made by sticking fluororesin films on both sides of the base fabric woven by expanded PTFE fibers. Because of its high cost, this membrane material is rarely used in general buildings and few foreign manufacturers, considering both cost and performance.
ETFE
Directly made of ETFE (ethylene-tetrafluoroethylene * * *) raw materials. ETFE not only has excellent impact resistance, electrical properties, thermal stability and chemical corrosion resistance, but also has high mechanical strength and good processability. The application of ETFE membrane can replace other products in many aspects, showing strong advantages and market prospects. This film material has excellent light transmittance and is called "soft glass", and its weight is only 1% of that of glass of the same size. Good toughness, high tensile strength, not easy to tear, ductility greater than 400%; Strong weather resistance and chemical corrosion resistance, and the melting temperature is as high as 200℃; Can effectively use natural light and save energy; Good acoustic performance. The self-cleaning function makes the surface difficult to be polluted, and a small amount of polluted dirt can be removed by rainwater flushed zone. The cleaning cycle is about 5 years. In addition, ETFE film can be prefabricated into film bubbles, which is convenient for construction and maintenance. ETFE also has some shortcomings, such as the external environment is easy to damage materials, leading to air leakage, high maintenance costs and so on. However, with the construction of large stadiums, tourist sites and waiting halls. ETFE has highlighted its own advantages. Only a few companies such as ASAHI (Japan) (AGC) and Kewell (Germany) can provide ETFE membrane materials, and the developed countries abroad have only developed and applied this membrane material for more than ten years.
Shijiazhuang Zhuoken Membrane Structure Engineering Co., Ltd. is a membrane structure company specializing in tensioned membrane structure, ETFE membrane structure, PTFE membrane structure, landscape membrane structure, cable membrane structure, space membrane structure, membrane structure garage, membrane structure parking shed, membrane structure stand, membrane structure sunshade and membrane structure canopy. The business covers Shijiazhuang, Baoding, Tangshan, Langfang, Xingtai, Zhangjiakou, Chengde, Cangzhou, Hengshui, Handan, Qinhuangdao and other cities, and it is one of the largest professional membrane structure companies in China.