What is the membrane structure of the Water Cube?

ETFE transparent and medium blue membrane material.

The membrane structure of the Water Cube is made of ETFE membrane, which is scientifically known as ethylene tetrafluoroethylene copolymer.

ETFE film is usually less than millimeter thick and is a transparent film. It is often made into an air cushion and used in the membrane structure. The earliest ETFE project has a history of more than 20 years, and the most famous one is the Yior Zhizhidian Garden in the United Kingdom.

ETFE membrane is a high-quality alternative to transparent building structures and has proven itself as a reliable and cost-effective roofing material in many projects over the years with its many advantages. The membrane is made of artificial high-strength fluoropolymers, and its unique anti-adhesive surface makes it highly stain-resistant, easy-to-clean and easy to clean. Usually rainwater removes the main dirt.

The full name of the Water Cube is the National Aquatics Center, located in the Beijing Olympic Park, one of the landmark buildings of the 2008 Beijing Olympic Games. It and the National Stadium are located on both sides of the north end of Beijing's central axis, forming a relatively complete image of Beijing's historical and cultural city. During the Beijing Olympics, a total of 25 world records were broken in various events held in the Water Cube.

To put it simply, it is blown out with air, not the one that is blown out, but the ethylene tetrafluoroethylene copolymer film that is solid with mu, also known as e t f e film, blown into the air, and then built up. So what is the e t f e membrane? In fact, it is an organic synthetic material, which was first developed in the seventies of the last century.

It started as an insulating material in the aviation industry. Later, with the continuous improvement of the technical level, it can be processed into this kind of flake. That's the precursor to this e t f e.

When building the Water Cube, how can you sew two layers of membrane together, and then blow air into it? It is the bricks of different sizes that we see on the exterior wall of the Water Cube, which look very technological, and they call this an air pillow. Almost 3,000 air pillows were used for the entire Water Cube.

Some people may ask, is it strong to use this air-blown membrane as a water cube on the exterior wall? It's really a matter of thinking about this in engineering. In a very objective way, it is certainly impossible to say that the strength of this membrane structure is as high as that of a concrete structure.

But he also has his own strengths. The first is that he is light. The thickness of a layer of film is about millimeters.

So the burden on the entire building support is much smaller. In addition, the toughness, ductility and tensile strength of this e t f e film are also quite good. A person of normal weight has no problem playing with a trampoline on an air pillow.

I remember seeing an interview before, and the engineers of the Water Cube said that putting a car on it would not be crushed.

Taking a step back, if it's really broken, the membrane is broken, the air leaks and the grip is lost, then what should you do? The membrane structure of the Water Cube has an overall monitoring system. Air leaks can be detected.

If it is serious, it is not difficult to change the air pillow. The Water Cube's monitoring system is really powerful. Because the air pillow is filled with air, the temperature difference in Beijing is 50 degrees in a year, the air will expand and contract, and the air in the air pillow will expand in summer, will it burst the air pillow?

In winter, the volume of air becomes smaller. Will the Water Cube be deflated? This air monitoring system will play a role, which will adjust the pressure inside the air pillow, so that the water cube is always in a relatively good state.

。"Water Cube" is a combination of 12 hedron and 14 hedron with 6,700 tons of steel structure, and the membrane structure of the Water Cube is made of ETFE membrane material, which is a double-layer air pillow inflatable membrane structure, consisting of a total of 3,097 air pillows, covering an area of 10,000 square meters and an area of 260,000 square meters. ETFE membranes are a member of the plastic family.

It is light and thin, generally only millimeters thick, but it is very resistant. The air pillow made of this membrane has good weather resistance and can withstand rain and snow for many years. In addition, it has a very good light transmittance, with a light transmittance of 97%, which allows the swimming pool to receive more light and heat, helping the swimming pool to keep warm, saving 9% of energy costs compared to general energy-efficient buildings.

The Water Cube is a large-scale public building that is completely enclosed by membrane structure, which is a great challenge for the design and construction of ETFE membrane materials, ventilation and air conditioning, fire prevention, sound, light, electronic control, etc. In this almost transparent hall, the light is required to be scattered light, and there can be no glare that affects the athletes' competition; This closed pavilion should have a certain self-regulation function for the temperature difference, and cannot become a greenhouse; The wall made of this membrane material can absorb internal and external noise to a certain extent.

The Water Cube is a double-layer ETFE system, one layer on the outside and one layer on the inside, the quality of this ETFE membrane material is only 1% of that of the same size glass, it has good toughness, it can absorb more sunlight, and it will not spontaneously combust, in addition, they also have a wonderful self-cleaning function.

ETFE membranes.

Self-cleaning: The surface of the membrane structure is basically free of dust. Except in extreme weather such as sandstorms, natural precipitation is generally sufficient to keep it clean and new.

Energy-saving: More than 3,000 translucent air pillows can make most areas of the swimming center unlit during the day, and the light entering the room is the softest.

Thermal insulation: In terms of temperature control alone, the membrane structure can help the "Water Cube" save 30% of electricity.

The outer membrane structure of the "Water Cube" is made of ETFE material, which is light in texture, but the strength is beyond imagination, and it can withstand the rolling of cars after inflation; The ductility of the film is very good, and the fire resistance, heat resistance are obvious. It can be pulled to three to four times its length without breaking, and the ignition point must be above 715 degrees to burn into a hole, but it does not spread, and there is no smoke, and no burning material falls.

This is the world's first fully enclosed stadium with a large area of ETFE.

The membrane on the surface of the Water Cube is an ETFE membrane material.

The characteristics of ETFE membrane materials include the following aspects:

1) High optical performance: It is mainly reflected in the high light transmittance, at least above 90%, and at the same time, the light transmittance of the material has a certain selectivity and controllability. You can choose to let ultraviolet light pass through to ensure the photosynthesis of plants in the room, or you can reduce the light transmittance by printing patterns on the surface of the film, and you can also make different colors of ETFE films (e.g.

White, red, blue, black, etc.) are colorful, and at the same time, they can also reduce the light transmittance. (2) Good ductility: The membrane material has excellent tensile and ductility, high yield strength and breaking strength, and the characteristics of good ductility are also the fundamental reasons for the diversified development of ETFE membrane structure.

2) Stable chemical properties: ETFE membrane has good acid and sulfur resistance, and can be used in various climates.

3) Physical properties: The membrane material has certain flame retardancy, self-cleaning performance, high anti-fouling and easy to clean.

The Water Cube building uses ETFE membrane material, which is a transparent membrane material.

With a service life of at least 25-35 years, ETFE membranes are ideal for use in permanent, multi-layered movable roof structures.