S u b m i t t e d b y

M A I T R E Y I Y E L L A P R A G A D A

B A 0 7 A R C 0 0 7

Membrane structures are one sort of spatial structures made of tensioned

membranes. Tensile structures is architecture of new generation as well as

possibility to supplement traditional architectural solutions. Tensioned

membrane material is considered to be the fifth construction element after

metal, stone, glass, and concrete. Structures are easy to combine and

coordinate with other materials, such as wood, glass, stainless steel

structures, connections, as well as cables, and since the material used is

light translucently, incredibly attractive and luxurious image of the structure

is obtained if properly arrange illumination of the structure.

MEMBRANE STRUCTURES

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Membrane structures are one sort of spatial structures made of tensioned membranes.

The common membranes include fabrics such as PVC coated polyester fabric,

translucent Polyethylene Fabrics, PVC coated glass fiber fabric and PTFE coated glass

fiber fabric; foils like ETFE foil and PVC foil. According to different form-finding methods they

can be divide into pneumatic structure, tensile membrane structure, cable dome. In these three

kinds of membrane structures membranes work together with cables, columns and other

construction members to find a form. There are also some constructions built with membrane,

but it doesn't contribute to supporting the framework, such as the Beijing National Stadium. In

this building the PTFE coated glass fiber fabric and ETFE foil are only filled into the space

between large steel structures to build the large roof and facade. Membrane Structures are also

referred to as tension fabric building. Another building beside it--Beijing National Aquatics

Center--"Water cube" can be seen as one pneumatic membrane structure made of ETFE foil.

Membrane Structures provides one-off architecturally designed structures to suit specific client

requirements, and, alternatively, a range of standard designs that are cost effective and durable.

These permanent installations include architectural sails, arch-supported structures, conicals,

inverted conicals and other structures custom designed and built for a particular application.

Membranes may be fabricated in PVDF (fluorined polymer) and PTFE (teflon) coated fabrics if

full weather block-out is required. High strength mesh fabrics are also available.

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Types of Membrane structures :

Air-inflated membrane structure

Inflatable structures are supported by blowing air inside the structure, which is

reflected in their name. It could seem that this would be uncomfortable for visitors to

be inside of the structure; however air-pressure changes inside the structure are very

minimal and not more than natural barometrical fluctuations.

Types of air inflatable structures

There are a few main types of air domes, i.e. high and low profile (referring to the

height of the structure) structures:

High-profile constructions are mostly used when the structure is to be run

temporarily or periodically on a "zero" ground base.

Low-profile constructions are used for large-scale overall dimension structures,

such as stadiums, large sports complexes, etc. Also they are most often built

on buildings themselves, but not on a "zero" base level. Cross cables hold the

roof down.

Here are few samples of low and high profile structure types:

Covering material

The structure’s awning is calculated by estimating snow and wind loads according to

local building regulations. The material is welded and installed as a one-piece cover,

securing an absolute impermeability of the structure. The cover is manufactured from

flame retardant (DIN4102B1/M2 standard), light translucent material, both sides of

which are covered by an acrylic layer. It is possible to produce the structure from

blackout (light-proof) material of your chosen color. Special fastening units, produced

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from galvanized steel, arrange connecting structure to the ground.

Inner layer

In order to insulate the structure, minimize condensation, and improve acoustic

properties, an air-gap can be made by fitting an additional layer of PVC material from

the inside of an air supported structure.

Doors

For the main entrances to the structure revolving doors are used; direct-emergency

exits can also be installed.

Heating and air supporting system

Automatic heating and air supporting system is calculated for each structure, which

depend on the customer requests can use gas, oil, existing central heating or

electricity.

llumination

Upon customer's request, illuminators of the structure can be direct (hanging on the

ceiling) or indirect.

Additional information

Microclimate maintenance control system is designed and installed as an

additional package.

Sketches of the structure - drawings are presented and coordinated with a

customer before signing an agreement or, upon the customer's request, earlier.

All necessary technical documentation and warranty obligations are enclosed

to the products.

Air-supported membrane structure

An air-supported (or air-inflated) structure is any structure that derives its structural

integrity from the use of internal pressurized air to inflate a pliable material (i.e.

structural fabric) envelope, so that air is the main support of the structure.

Material

The materials used for air-supported structures are similar to those used in tensile

structures, namely synthetic fabrics such as fibreglass and polyester. In order to

prevent deterioration from moisture and ultraviolet radiation, these materials are

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coated with polymers such as PVC and Teflon.

Depending on use and location, the structure may have inner linings made of lighter

materials for insulation or acoustics.

Advantages and disadvantages

There are some advantages and disadvantages as compared to conventional

buildings of similar size and application.

Advantages:

Considerably lower initial cost than conventional buildings

Lower operating costs due to simplicity of design (wholly air-supported structures

only)

Easy and quick to set up, dismantle, and relocate (wholly air-supported structures

only)

Unobstructed open interior space, since there is no need for columns

Able to cover almost any project

Custom fabric colors and sizes, including translucent fabric, allowing natural

sunlight in

Disadvantages:

Continuous operation of fans to maintain pressure, often requiring redundancy or

emergency power supply.

Dome collapses when pressure lost or fabric compromised

Cannot reach the insulation values of hard-walled structures, increasing

heating/cooling costs

Limited load-carrying capacity

Conventional buildings have longer lifespan

Arch-supported membrane structure

A pre-stressed arch supported membrane structure, a method of assembly and

erection and a means of tensioning a membrane of double curvature supported by and

attached to upright arches. By moving the ends of flat resilient arch structural

members closer together, pre-stressed arches are formed by "bowing." Assembly and

erection consists of attaching flat arch member ends to base beams, one fixed and

one movable; attaching membranes to these flat members when reclined on the

ground, operatively attaching transverse or inclined arch members to their respective

structural members; moving the non-fixed base beam towards the fixed base beam

thus causing the arches to be formed as the structure rises to its erected position.

Preliminary tensioning of the membrane can take place when the transverse or

inclined arches are attached to the arch members in their reclined position. Final

membrane tensioning adjustments at the crown and at the base by moving the arches

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horizontally then anchoring the structure to the base, safely securing the base beams

and arch ends completes the erection of the main structure. An alternate method of

erection is provided by elimination of the base beams by fastening the arches directly

to the base. The support arches are bowed after being attached to the transverse or

inclined arches and then attached to the base by means of an adjustable fastener.

Lightweight end closures or doors may be assembled and partially attached before

erection to eliminate or decrease above ground assembly.

Cable-suspended membrane structure

A cable-suspended roof structure is provided to span wide areas as, for example,

stadiums, coliseums, arenas, playing fields and the like. More specifically, a roof is

provided in which cables under tension extend between substantially centrally located

tension ring means and a surrounding continuous or enclosed ringlike compression

member, their ends being anchored securely therein and said cables being under

tension. An upper and a lower double layer of cables is employed and compression

spreader means spanned between each cable of either set and each of the proximate

cables of the other set.

cable-roof structure is particularly adapted to cover wide areas in part because it is

the most economical method of spanning such wide areas and in part because of its

lightness, structural and architectural advantages are to be derived. A cable-roof

structure is one in which steel cable is the load-bearing, structural element and the use

of trusses and beams and intermediate supporting columns may largely be avoided.

This invention, more specifically, is concerned with a cable-suspended structure which

quite simply can be produced as a roofing structure having a substantial lightness

while at the same time being inherently stable under both positive and negative

loading conditions. Further, this invention is concerned with the use of cables in a

cable-roof suspension system in which the individual cables are kept in equilibrium

and the inherent elastic stability of cable suspenders is dampened and restrained to

combat motion, sometimes referred to as "flutter" which may occur upon being

subjected to exterior dynamic forces as in the case of wind, mobile and seismic load

and, conceivably, from sound waves or vibrations in the ground set up by vehicular

traffic. In this invention cables function as suspenders between a centrally or medially

located tension ring and surrounding an elevated compression structure wherein the

cables are under tension. More particularly, two layers or sets of cables are employed.

One set is superposed with respect to the other set in such manner that each cable of

the superposed set divides the space between the proximate cables of the lower set

and each cable of the upper set is in relation to each cable of the lower set

equidistantly spaced there between and compression spreader means is securely

fixed at its ends to said closely adjacent cables of the two sets. It is also a part of the

invention to arrange that the compression spreader means function as roofing and

space enclosing element to shield the area beneath the cable from the forces of

nature.

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Frame-supported membrane structure frame supported fabric structures offer the most inexpensive alternative solution for

temporary or permanent industrial enclosures. Designed for specific climate and

application, including warehousing, construction site enclosures, hazardous waste

disposal and clean-up site enclosures, waste treatment pond enclosures, bulk storage

of fertilizers and ore, radar antenna enclosures, coffee and other grain warehousing.

Most cost effective enclosure

Rapid delivery

Quick and simple installation and dismantle

Energy efficient

World-wide installations

Frame Supported, Tensile Membrane Structure shall be a pre-engineered system of

standard metal framing components and membrane enclosure designed to provide

gross square feet of fully-enclosed space and shall include the following:

1. Flat gable ends to maximize interior dimensions.

2. The side, and end, wall construction shall accept passage and exit doors.

3. Exterior membrane shall run continuous from eave to eave or base of structure to

base of structure.

4. Exterior membrane will be fabricated for post-installation tensioning in both primary

grid directions; draped or loose-laid membrane installation is not acceptable.

5. Exterior membrane will be colors selected by the Architect from Manufacturers’

standard line.

6. Exterior membrane shall, upon completion, provide a continuous weather-tight

enclosure.

7. Upon installation and tensioning of the exterior membrane it will be smooth and

wrinklefree and shall remain so under anticipated thermal and live-load conditions.

8. Membrane shall be repairable without the need to dismantle any portion of the

structural framing.

9. Membrane shall be attached to framing that allows for ventilation fans or HVAC

duct penetrations.

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Mast-supported membrane structure Likewise a typical ‘lightweight’ canopy with masts and cable tie backs to ground level

will generally need significant concrete foundations or screw anchors to resist the

tensile loads. Loading analysis derived from a computer model is offered to all clients

where it is felt that there is a need, and can give typical loads directions and the size of

the design loads.

Mast supports can be internal, peripheral or both. Internal masts create peaks in the

roof. They may carry their load directly to their foundations. However, to prevent

blocking the view of spectators, they can be cut short, and placed on top of trusses,

which are extended between peripheral support.

Tensegrity cable membrane structure Tensegrity, tensional integrity or floating compression, is a structural principle based

on the use of isolated components in compression inside a net of continuous tension,

in such a way that the compressed members (usually bars or struts) do not touch each

other and the prestressed tensioned members (usually cables or tendons) delineate

the system spatially.

ensegrity structures are structures based on the combination of a few simple but

subtle and deep design patterns:

loading members only in pure compression or pure tension, meaning the structure

will only fail if the cables yield or the rods buckle

preload or tensional prestress, which allows cables to be rigid in tension

mechanical stability, which allows the members to remain in tension/compression

as stress on the structure increases

Truss-supported membrane structure This lightweight and 3-dimensional space frame system, designed to support

membrane and other materials, makes it possible to do roofing for a large clear-span

buildings. The membrane structure supporting system uses trusses created by joining

pieces of steel tubing together with spherical steel nodes. The resulting framework is

exceptionally strong and aesthetically pleasing, permitting a wide range of design

choices for virtually any size construction. The component-based truss system

facilitates assembly, and also permits disassembly and reusability. All aspects of a

project, from design through fabrication of our steel truss system, are carefully

controlled by an integrated computer system. This assures every completed structure

will have maximum strength, durability and aesthetic qualities.

A structural truss has upper and lower wooden chords separated along their lengths

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by vertical wooden struts. The chords and struts are joined together to form the truss

frame solely by adhesive-backed paper membranes covering the opposite sides of the

frame so as to transmit tensile stresses within the frame. The truss may be

manufactured in multiples of various lengths by a continuous assembly line process.

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Tensile structures is architecture of new generation as well as possibility to supplement

traditional architectural solutions. Tensioned membrane material is considered to be the fifth

construction element after metal, stone, glass, and concrete.

Tensile membrane structures are used as:

stadiums, sports facilities, exhibition halls, business centers, concert halls and etc.;

shade roofs of the entrance of hotels, restaurants, cafes, and other commercial

buildings;

airport roofs, bus, train stations and terminals, car parking and gas stations;

other permanent or temporary structures.

Singularities of architecture textile structures:

Aesthetic image and luxurious tone -Architects fit textile structures to a specific

environment or building, therefore each project becomes individual. Structures are easy

to combine and coordinate with other materials, such as wood, glass, stainless steel

structures, connections, as well as cables, and since the material used is light

translucently, incredibly attractive and luxurious image of the structure is obtained if

properly arrange illumination of the structure.

durability - Special PVC, PVDF or Teflon layer covered materials, which does not attract

dust can be used for these structures, so aesthetic image does not change for more than

25 years