Pneumatic Structure

pneumatic structure

Membrane structure that is stabilized by the pressure of compressed air. Air-supported structures are supported by internal air pressure. A network of cables stiffens the fabric, and the assembly is supported by a rigid ring at the edge. The air pressure within this bubble is increased slightly above normal atmospheric pressure and maintained by compressors or fans. Air locks are required at entrances to prevent loss of internal air pressure. Air-supported membranes were first devised by Walter Bird in the late 1940s and were soon put to use as covers for swimming pools, temporary warehouses, and exhibition buildings. Air-inflated structures are supported by pressurized air within inflated building elements that are shaped to carry loads in a traditional manner. Pneumatic structures are perhaps the most cost-effective type of building for very long spans.

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pneumatic structure

A very lightweight enclosed structure, usually fabricated of a membrane of an impervious material and supported by the difference in air pressure between the exterior and the interior of the structure rather than by a structural framework. Fans must maintain the interior pressure slightly in excess of normal atmospheric pressure to prevent the structure from slowly deflating and collapsing. Used primarily as a temporary enclosure or to house sports facilities such as tennis courts and swimming pools. Also called an air-supported structure.

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Pneumatic Structure 

a soft envelope whose internal volume is supplied with atmospheric air from pumping equipment (fans, blowers, or compressors) to provide stability and resistance to external loads (supporting capacity). The first such structures were used in 1946 by the engineer W. Bird (USA) for the housing of a radar antenna structure. They subsequently became popular in many countries.

The envelopes of pneumatic structures are made of industrial fabrics coated with polymers, including rubber, or from reinforced films. Threads of synthetic fibers, or less frequently glass fibers, provide the reinforcement for the films and fabrics.

Pneumatic structures are divided into two types: air-supported structures, in which air under low pressure (excess pressure, 0.1–1 kilonewton per sq m [kN/m²]) is fed directly under the envelope, and air-inflated structures, in which air under high pressure (excess pressure, 30–700 kN/m²) fills only the supporting elements of the structure.

In the erection of air-supported pneumatic structures, the envelope is tightly fastened to the foundation. Airlocks are constructed for entering and leaving the building. Air-inflated structures are subdivided into inflated-frame and inflated-panel types. Also in use are hybrid envelopes of air-supported and supporting structures, as well as reinforcing cables, nets, stays, and membranes.

The advantages of pneumatic structures are light weight, the possibility of covering large spans without internal supports, complete prefabrication, rapid assembly, portability, transparency to light and radio waves, and low cost. Their disadvantages are the need for continuous maintenance of excess pressure in the envelope, the relatively short service life, and the poor fire resistance and acoustic insulation.

The use of pneumatic structures is expedient for permanent and temporary buildings for a variety of purposes (production and storage areas, as well as halls for performances, sports, trade, or exhibitions), mobile buildings (maintenance stations, medical aid stations, clubhouses, and libraries), transportation and hydro-engineering structures (bridges, dams, and gates), and auxiliary facilities in performing construction work (hoists, winter shelters, and formwork).

REFERENCES

Otto, F., and R. Trostel. Pnevmaticheskie stroitel’nye konstruktsii. Moscow, 1967. (Translated from German.)
Pnevmaticheskie konstruktsii vozdukhoopornogo tipa. Moscow, 1973.
Dent, R. N. Principles of Pneumatic Architecture. London, 1971.

V. V. ERMOLOV