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Introduction0 Membrane structure that is stabilized by the pressure of compressed

air.0 Air-supported structures are supported by internal air pressure.

0 A network of cables stiffens the fabric, and the assembly is supportedby a rigid ring at the edge.

0 The air pressure within this bubble is increased slightly above normalatmospheric pressure and maintained by compressors or fans.

0

Air locks are required at entrances to prevent loss of internal airpressure.

0 The first such structures were used in 1946 by the engineer W. Bird(USA) for the housing of a radar antenna structure. They subsequentlybecame popular in many countries and were soon put to use as coversfor swimming pools, temporary warehouses, and exhibition buildings.

0 Air-inflated structures are supported by pressurized air within inflated

building elements that are shaped to carry loads in a traditionalmanner.

0 Pneumatic structures are perhaps the most cost-effective type ofbuilding for very long spans.

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0 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 structurerather than by a structural framework.

0 Fans must maintain the interior pressure slightly in excess of normal

atmospheric pressure to prevent the structure from slowly deflating

and collapsing.

0 Used primarily as a temporary enclosure or to house sports facilitiessuch as tennis courts and swimming pools. Also called an air-

supported structure.

0 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.

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Pneumatic structures are divided into two types:

0 Air-supported structures, in which air under low pressure (excess

pressure, 0.1

1 kilo newton per sq. m [kN/m2]) is fed directly underthe envelope,

0 Air-inflated structures, in which air under high pressure (excesspressure, 30700 kN/m2) fills only the supporting elements of thestructure.

Construction

0 In the erection of air-supported pneumatic structures, the envelope istightly fastened to the foundation.

0 Airlocks are constructed for entering and leaving the building.

0 Air-inflated structures are subdivided into inflated-frame and inflated-panel types.

0 Also in use are hybrid envelopes of air-supported and supportingstructures, as well as reinforcing cables, nets, stays, and membranes.

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Roof for a Stadium

A Pneumatic Structure

Other Pneumatic Structures

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0 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.

0 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.

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0 The use of pneumatic structures is

Expedient for permanent and temporary buildings for a variety of

purposes (production and storage areas,

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).