The membrane structure project is divided into 7 categories, which are:
1) Pure steel arch structure
Using the traditional beam and column system, the roof is a round arch type , the distance between columns and beams is generally about 8m.
2) The main body of the concrete structure plus steel arches
The above two simplest membrane structures can have many changes according to the plane shape, such as square, diamond, etc., and the spacing of the arches Determined according to the strength of the membrane material used, design load, wind force, etc.
3) Concrete main structure plus steel cables
The ridge is curved upward and is located under the membrane cloth, and the valley cable is curved downward and is located above the membrane. The bending directions of the two steel cables are stretched in opposite directions, causing vertical forces in opposite directions, causing the membrane to be subject to vertical tension, and the horizontal tension in the membrane cloth is directly stretched.
4) Concrete main structure plus steel columns
5) Tensile tent membrane structure
6) Large-scale (span more than 200m) air-supported membrane Structure
Using steel cables made of flat steel and membrane cloth, a giant roof with a long span can be made. This kind of building has simple structure, convenient construction, high economic benefits and no need for maintenance. However, because it needs to be kept closed all year round and it is inconvenient to enter and exit, it is no longer newly built, but it is still a good structural form. Since the membrane structure requires precise design and tailoring to achieve the desired effect, David and Geiger, along with colleagues Mike and Mark from Columbia University and Joseph and Wright, jointly developed a nonlinear steel cable calculation program for The design of the gas-supported large-scale membrane roof project has laid the foundation. From 1973 to 1978, 12 large-scale indoor stadiums with air-supported membrane structures were built around the world. Compared with other stadiums completed during the same period, these membrane structure stadiums were not only cheaper, but also faster to construct. The roof of the 40,000m2 Silverdome Stadium was completed in just 11.5 months. It is the largest indoor stadium in the world.
7) Steel cable dome
Around 1980, Mr. Geiger created a new technology using a permanent membrane structure
This new technology is Based on engineering philosopher Buckminster. Fuller's theory. Fuller believed that modern structures are fighting against the gravity of the earth and constantly striving for the continuity of pressure, but this is not the case in nature. This is a philosophy that may seem plain, but is actually very wise. In an article he published in 1983, he suggested gradually reducing the impact of pressure on the structure and increasing the role of tension. Fuller named his new concept "tension style" , English is a synthesis of the two words "Tension" and "Integrity". In this ideal structure "the pressure member is an island in a sea of ??tension." Mr. Geiger further explained Fuller's philosophy. He believed that "the span of space is completed by continuous tension cables and discontinuous pressure rods." On the basis of this theory, he proposed that the cable dome is composed of the following members: the central tension ring reaches the pressure ring through a number of multiples of four notochores, ring cables, relay stay cables, pressure rods and stay cables. Beams form a complete closed tension arch structure system.
This invention was patented. Because it does not require air support and is relatively simple to manufacture, it has gradually replaced the air-supported membrane structure in the construction of large venues. In terms of structural technology, the steel cable dome uses the principle of prestressing to establish a new concept that completely breaks through traditional thinking.
The steel cable structure is prestressed, so that the original pressure rods become tension parts and are replaced by steel cables. This reduces the number of pressure rods and forms a very lightweight structure. Dome structure. The weight of a traditional steel frame structure increases dramatically as the span increases, but in the structural system of a steel cable dome, the unit weight always remains the same. This is a breakthrough in structural theory.
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