This document discusses pneumatic structures, which are membrane structures supported by air pressure. It defines pneumatic structures as membranes carrying loads through tensile stresses and stabilized by prestressing the membrane through external forces or internal pressurization. The document then covers the origins of pneumatic structures, how they work, their key characteristics like being lightweight and flexible, different types including air-supported and air-inflated, materials used, and historical uses.

1. STRUCTURE SYSTEM

2. PNEUMATIC STRUCTUREPNEUMATIC STRUCTURE
INTRODUCTION :-INTRODUCTION :-
•PNEUMATIC STRUCTURE IS A MEMBRANE WHICH CARRIES LOAD
DEVOLPED FROM THE TENSILE STRESSES.
•ITS STABLIZATION IS DONE BY PRESTRESSING THE MEMBRANE EITHER
BY:-
a) APPLYING AN EXTERNAL FORCE WHICH PULLS THE MEMBRANE TAUT
b) INTERNAL PRESSURIZING IF THE MEMBRANE IS
VOLUME ENCLOSING. SUCH STRUCTURES ARE CALLED “PNEUMATIC
STRUCTURES”.
•THESE STRUCTURES CAN CREATE ARTIFICIAL ENVIRONMENTS
ADAPTABLE TO HUMAN USE .
•THE PNEUMATIC FORMS ARE BOUND TO
INCREASE N POPULARITY, OWING TO
THE TREMENDOUS FREEDOM THEY
PROVIDE TO THE ARCHITECTS IN
DESIGNING LARGE FREE SPACES
WITHIN THEM.

3. ORIGINORIGIN :-
• THE WORD PNEUMATIC IS DERIVED FROM THE GREEK WORD
“PNEUMA”(MEANING BREATH OF AIR) ,THUS THESE ARE THE STRUCTURE
WHICH ARE SUPPORTED BY AIR.
• “PNEUMATIC STRUCTURE” HAS BEEN USED
• BY MANKIND FOR THOUSAND OF YEARS.
• BUT IN THE BUILDING TECHNOLOGY IT WAS
• INTRODUCED ONLY ABOUT 40 YEARS AGO.
PRINCIPLE:-PRINCIPLE:-
1) ITS PRINCIPLE IS THE USE OF RELATIVELY THIN MEMBRANE
SUPPORTED BY A PRESSURE DIFFERENCE.
2) THROUGH INCREASING THE INSIDE AIR PRESSURE NOT ONLY THE
DEAD WEIGHT OF THE SPACE ENVOLPE IS BALANCED, BUT THE
MEMBRANE IS STRESSED TO A POINT WHERE IT CANNOT BE
INDENTED BY ASYMMETRICAL LOADING .
GENERAL CHARACTERISTICSGENERAL CHARACTERISTICS:-
1) LIGHT WEIGHT:-1) LIGHT WEIGHT:-
a) THE WEIGHT OF THE STRUCTURE AS COMPARED TO THE AREA IT
COVERES IS VERY LESS

4. 2) THE WEIGHT OF THE MEMBRANE ROOF , EVEN WHEN IT IS STIFFENED
BY CABLES, IS VERY SMALL
3) LOW AIR PRESSURE IS SUFFICIENT TO BALANCE IT
4) EVEN WITH SPANS OF MORE THAN 100MTS, THE WEIGHT OF THE
STRUCTURE DOES NOT EXCEED 3KG/SQUARE METRE .
2)2) SPANSPAN :-
• NO STRUCTURE CAN GURANTEE TO GIVE THE SPANS UPTO CERTAIN
LIMITS CABLE STRUCTURES ARE EXCEPTIONS( CABLES FOR BRIDGES
USUALLY).
• FOR A BUILDING, THEN THE LIMITATION IS 500 FEET SPAN DUE TO
ITS SELF WEIGHT.
• ANOTHER ADVANTAGE OVER OTHER STRUCTURES IS THAT, FOR
PNEUMATIC MEMBRANE , THERE IS NO THEORTICAL MAXIMUM SPAN AS
DETERMINED BY STRENGTH, ELASTICITY, SPECIFIC WEIGHT OR ANY
OTHER PROPERTY.
• IT IS HARDLY POSSIBLE TO SPAN A DISTANCE OF OVER 36KM. WITH A
STEEL CABLES AS THEY WOULD FAIL BECAUSE OF THEIR INABILITY TO
SUSTAIN THEIR OWN WEIGHT. BUT WITH PNEUMATICS, SUCH SPANS
ARE QUIET POSSIBLE.
3) SAFETY3) SAFETY:- PNEUMATIC STRUCTURES ARE SAFER THAN ANY OTHER
STRUCTURE. OTHERWISE, A PROPER CARE SHOULD BE TAKEN WHILE

5. ESTABLISHING
• ACCIDENTAL CIRCUMSTANCES ARE AVOIDED AS THEY ARE VERY
LIGHT.
• THERE ARE WARNING SIGNALS WHILE THE RELEASE OF RETURN
VALVE. SAFETY FACTOR+ WARNING TIME IS QUIET LONG AS
COMPARED TO OTHER STRUCTURES.
• PNEUMATIC STRUCTURES CANT BE DESTROYED BY FIRE QUICKLY AND
TOTALLY.
4.4. THEFTTHEFT:- IT IS VERY SAFE NO BODY CAN OR PASS THROUGH A
PNEUMATIC STRUCTURE. IF AN AIR BAG IS CUT WITH A KNIFE/ PIN, A
BANG IS PRODUCED.
5.5. HUMAN HEALTH:-HUMAN HEALTH:-IN MOST CASES, PRESSURE OF NOT MORE THAN 80-
100mm AND NOT LESS THAN 60mm.BUT MAN CAN WITHSTAND
PRESSURES BETWEEN 0.20 ATM TO 3 ATM. THEREFORE NO HEALTH
HAZARD IS PRESENTED BY CONTINOUS STAY IN A PNEUMATIC
STRUCTURE.
6.6. QUICK ERECTION AND DISMANTLINGQUICK ERECTION AND DISMANTLING:- SUITABLE FOR TEMPORARY
CONSTRUCTIONS BECAUSE THEY ARE AS EASY TO DISMANTLE AS TO
ESTABLISH.
• 1 SQ.KM. OF AN AREA CAN BE BROUGHT DOWN IN 6 HOURS. AND
ESTABLISH IN LESS THAN 10 HOURS. THE 4 HOURS DIFFERENCE IS DUE
TO ESTABLISHMENT OF PEGS ETC.

6. 6. ECONOMYECONOMY:- IT IS NOT EXPENSIVE WHERE IT IS USED FOR SHIFTING
STRUCTURES. FOR PERMANENT STRUCTURES, IT IS VERY
EXPENSIVE. OTHERWISE THE COST PER SQURE FOOT OF AIR
SUPPORTED STRUCTURES IS AMONG THE LOWEST FOR LARGE SPAN
ROOFS.
GOOD NATURAL LIGHTGOOD NATURAL LIGHT:- GIVES GOOD NATURAL LIGHT AS
TRANSLUCENT/TRANSPARENT PLASTIC SHEETS ARE USED TO
COVER AIR BAGS.WE CAN EVEN BRING THE WHOLE SUN INSIDE.
THERE IS A LOT OF FLEXIBILITY IN GETTING SUN LIGHT(50%-80%).

7. TYPES OF PNEUMATIC STRUCTURES:-
THESE ARE PRIMARY CLASSES OF PNEUMATIC STRUCTURES:- AIR
SUPPORTED STRUCTURES AND AIR –INFLATED STRUCTURES
AIR – SUPPORTED STRUCTURESAIR – SUPPORTED STRUCTURES:- IT CONSIST OF A SINGLE
MEMBRANE(ENCLOSING A FUNCTIONALLY USEFUL SPACE) WHICH IS
SUPPORTED BY A SMALL INTERNAL PRESSURE DIFFERENCE.THE
INTERNALVOLUME OF A BUILDING AIR IS CONSIQUENTLY AT A
PRESSURE HIGHER THAN ATMOSPHERIC. THE AIR SUPPORTED
STRUCTURE USES A LOW POSITIVE PRESSURE TO SUPPORT A
MEMBRANE OVER A GIVEN AREA. AIR MUST BE SUPPLIED CONTANTLY
BECAUSE OF THE CONTINOUS LEAKAGE, PRIMARILY THROUGH THE
BUILDINGS USED MOST OFTEN BECAUSE OF:
. THEIR RELATIVELY LOW COST
. THEIR SIMPLICITY OF DESIGN AND FABRICATION

8. AIR – INFLATED STRUCTUREAIR – INFLATED STRUCTURE:-IT IS SUPPORTED BY PRESSURIZED AIR
CONTAINED WITHIN INFLATED BUILDING ELEMENT. THE INTERNAL
VOLUME OF BUILDING AIR REMAINS AT ATMOSPHERIC PRESSURE.
THE PRESSURIZED AIR IN THE PILLOW SERVES ONLY TO STABLIZING
THE LOAD CARRYING MEMBRANE . THE COVERED SPACE IS NOT
PRESSURIZED .
ADVANTAGES OF AIR- INFLATED / AIR FRAME STRUTURE :-
. THE ABILITY FOR SELF SUPPORT
. THE POTENTIAL TO SUPPORT AN ATTACHED STRUCTURE

9. CLASSIFICATION OF PNEUMATIC STRUCTURESCLASSIFICATION OF PNEUMATIC STRUCTURES:-
PNEUMATIC STRUCTURES CAN BE FURTHER SUBDIVIDED AS:-
1)TYPE OF DIFFRENTIAL PRESSURE
2)DEGREE OF DIFFRENTIAL PRESSURE
3)TYPE OF SURFACE CURVATURE
4)PROPORTIONS
1.1. TYPE OF DIFFRENTIAL PRESSURETYPE OF DIFFRENTIAL PRESSURE:-.
a) PNEUMATIC STRUCTURES USE EITHER
POSITIVE PRESSURE OR NEGATIVE PRESSURE.
b) IN (+) PRESSURE SYSTEM,THE MEMBRANE
IS ALWAYS CURVED OUTWARDS,WHEREAS IN
NEGATIVE PRESSURE SYSTEMS THE MEMBRANE IS CURVED INWARDS.
c) BEING CURVED INWARDS THERE IS A TENDENCY OF WATER LOGGING
& SNOW ACCUMULATION .
d) MOREOVER,NEGATIVE PRESSURE SYSTEMS REQUIRE HIGH
SUPPORTS AT THE EDGE OR IN THE CENTRE WHICH MAKES IT MORE
EXPENSIVE.
e) BOTH OF THESE SYSTEMS ARE USED FOR STORAGE PURPOSES AS
THEY CAN KILL THE RODENTS.

10. 2.2. DEGREE OF DIFFERNTIAL PRESSUREDEGREE OF DIFFERNTIAL PRESSURE:-
LOW PRESSURE SYSTEMS -
THESE SYSTEMS ARE PROVIDED WITH
LOW PRESSURE AIR ;HENCE HAVE TO
BE PROVIDED WITH CONTINUOUS SUPPLY
OF AIR.EG-AIR SUPPORTED STRUCTURES.
HIGH PRESSURE SYSTEMS -
USED FOR EASY ERECTION & DISMANTLING
; THE PRESSURE DIFFERENCE IS B/W
2000-7000MM OF WATER PRESSURE
(100 TO 1000 TIMES) LOW PRESSURE
SYSTEMS.THESE HIGH PRESSURE AIR
INFLATED SYSTEMS ARE EITHER HAVING
A SINGLE VALVE SYSTEM OR A DOUBLE
VALVE SYSTEMS WHICH AVOIDS IT’S
COLLAPSE.

11. TYPE OF SURFACE CURVATURESTYPE OF SURFACE CURVATURES:- THESE STRUCTURES CAN ALSO BE
CLASSIFIED ACCORDING TO THE TYPES OF CURVATURE ON THE OUTER
SURFACE-
a)SINGLE CURVED
b)DOUBLY CURVED IN THE SAME DIRECTION OR SYNCLASTICS
c)DOUBLY CURVED IN OPPOSITE DIRECTION OR ANTICLASTIC
4. PROPORTIONSPROPORTIONS:- ON THE BASIS OF DIFFERENT PROPORTIONS,
PNEUMATIC STRUCTURES CAN BE:-
TWO DIMENSION OF SIMILAR SIZE AND ONE LARGER DIMENSION,
EG:-“TUBES”,”MASTS”,”COLUMNS”,”TOWERS”.
TWO DIMENSIONS OF SIMILAR SIZE AND ONE SMALLER DIMENSION, EG:-
“CUSHIONS”, ”LENSES”, ”DISCUSS”,”MATTRESSES”.
THREE DIMENSIONS OF SIMILAR SIZE,
EG:- “BALOONS”,”BALLS”,”SPHERES”, ”BUBBLES

12. 5. MATERIALS:-
ISOTROPIC:-ISOTROPIC:- THESE SHOW THE SAME STRENGTH AND STRETCH IN ALL
DIRECTIONS. EXAMPLES ARE:-
PLASTIC FILMSPLASTIC FILMS:- THESE ARE PRIMARILY PRODUCED FROM PVC, POLY
ETHYLENE, POLYESTER, POLYAMIDE ETC.
FABRICS:-FABRICS:- THESE MAY BE MADE OF GLASS FIBRES OR SYNTHETIC
FIBRES WHICH ARE COATED IN A PVC, POLYESTER OR POLYURETHENE
FILM.
RUBBER MEMBRANERUBBER MEMBRANE:- THEY ARE THE LIGHTEST AND MOST FLEXIBLE.
METAL FOILS:-METAL FOILS:- THEY POSSESS A VERY HIGH GAS DIFFUSION
RESISTANCE
AND HIGH TENSILE STRENGTH . ONE OF THE MAJOR PROBLEMS IN THE
USE OF METAL FOILS IS IN NEED TO PRODUCE VERY EXACT CUTTING
PATTERNS

13. AN ISOTROPIC MATERIALSAN ISOTROPIC MATERIALS:- THESE DO NOT SHOW THE SAME
STRENGTH AND STRETCHABILITY IN ALL DIRECTIONS. THEY HAVE
DIRECTION ORIENTED PROPERTIES. EXAMPLES ARE:-
WOVEN FABRICSWOVEN FABRICS:- THEY HAVE TWO MAIN DIRECTION OF WEAVE.
THEY CAN BE MADE OF:-
. ORGANIC FIBRES EG:- WOOL,COTTON OR SILK.
. MINERAL FIBRES EG:- GLASS FIBRES.
. METAL FIBRES EG:- THIN STEEL WIRES.
. SYNTHETIC FIBRES EG:- POLYAMIDE, POLYESTER AND POLYVINYLE.
GRIDDED FABRICGRIDDED FABRIC:- THESE ARE COARSE-WEAVE MADE OF
ORGANIC MINERAL OR SYNTHETIC FIBRES OR METALLIC NETWORKS.
THEY ARE PARTICULARLY USED WHERE MAXIMUM LIGHT
TRANSMISSION AND HIGH STRENGTH IS REQUIRED.
SYNTHETIC RUBBERSSYNTHETIC RUBBERS:- COMBINATION OF PASTIC AND RUBBER.
THEY CAN TAKE BETTER WEAR AND TEAR. THEY ARE LATEST AND ARE
MORE RESISTANT TO ELONGATION.
PLASTICSPLASTICS:- LIKE WOVEN FABRICS. ITS ADVANTAGE IS THAT THEY
HAVE MORE OF TENSILE STRENGTH THAN NORMALLY MANUFACTURED
PLASTIC SHEETS.

14. PNEUMATIC STRUCTURES Usages in HistoryPNEUMATIC STRUCTURES Usages in History::
HISTORICAL BACKGROUNDHISTORICAL BACKGROUND :-:-
THE TECHNOLOGY BEHIND PNEUMATIC STRUCTURES HAS BEEN LONG
KNOWN TO US. BUBBLES HAVE AROUSED PEOPLE’S CURIOSITY FOR
LONG. THE MORE IMMEDIATE USE OF PNEUMATICS HOWEVER LIES IN
BALOONS AND AIRSHIPS THAT HAVE GRACED OUR SKIES IN THE RECENT
PAST.
IN 1922, THE OASIS THEATRE IN PARIS SPORTED A PNUEMATIC HOLLOW
ROOF STRUCTURE THAT WAS ROLLED INTO PLACE WHEN IT RAINED.
DURING WORLD WAR PNEUMATIC STRUCTURES PLAYED AN IMPORTANT
ROLE AS ‘RADOMES’, WHICH HOUSED LARGE RADAR ANTENNAE.
THEY CAN CREATE ARTIFICIAL ENVIRONMENT ADAPTABLE TO HUMAN
USE IN ANY PART OF THE WORLD.