Base Fabrics, Tension structures, Air Structures, Clear Span Structures

Abstract:

There are several advantages of using a textile structure inarchitecture and construction. Fabric structures give freedom to architects todesign various shapes and appearances. Depending on the application the fabricmay require different properties. This paper reviews the application and scope.

Keywords: Architectural and Construction Textiles

Introduction:

Textiles are employed in many ways in the construction ofbuildings, both permanent and temporary, dams, bridges, tunnels and roads. Aclosely related area of use is in geotextiles by the civil engineering sector.

Temporary structures such as tents, marquees and awnings aresome of the most obvious and visible applications of textiles. Textiles arealso widely employed in the course of construction operations themselves, inuses as diverse as safety netting, lifting and tensioning ropes and flexibleshuttering for curing concrete.

Materials used:

Nonwoven glass and polyester fabrics are already widely usedin roofing applications while other textiles are used as breathable membranesto prevent moisture penetration of walls. Fibres and textiles also have a majorrole to play in building and equipment insulation.

Where these used to be exclusively made from proofed heavy cotton, a variety of lighter, stronger, rot-, sunlight and weatherproof synthetic materials are now increasingly required. A relatively new category ofarchitectural membrane is coming to prominence in the construction of semipermanent structures such as sports staid, exhibition structures and othermodern buildings.

Textiles for architecture and construction should beresistant to deformation and extension under tension and to wind and water. Thefabric must be waterproof, impermeable to air and wind, and resistant toabrasion and mechanical damage. It should also to be resistant to degradationfrom long-term exposure to sunlight and acid rain. Depending on the application,the fabric may need to transmit or reflect different levels of light. Theserequirements can be met by applying special coating to base fabrics.

Synthetic fibres allowed development of high performancefabrics with properties such as good strength, hydrophobicity, rot and fungiresistance which are essential properties of fabrics to be used as building andconstruction materials. Coated fabrics are now widely being used as theenvelope of large building constructions such as airports, stadiums, sportshalls, exhibitions and display halls, and storage bases for industrial andmilitary supplies. The fabric resists extremes of sunlight, temperature,biological attack, wind, rain and snow.

Base Fabrics

Base fabrics are usually made of synthetic fibres and formthe carrier layer which provides the necessary strength to the structure.Although aramid and carbon fibres have excellent properties, they are ratherexpensive to use in these types of construction extensively. The most widelyused materials are high tenacity polyester, fiberglass and nylon. Use ofsynthetic materials allowed lower backing fabric weight compared toconventional canvas fabric made of natural fibres.

Applications:

Tents:

Tents and shelters were probably the first constructions in which textiles were used as building materials. Tents have been traditionally used as building materials. Tents have been traditionally used for various purposes by nomadic people, traders, military, explorers and campers. New tent constructions were developed for building construction, business, exhibitions, entertainment, leisure and recreation. The most widely used fabrics for tent walls are polyesters and vinyls.

Clear-Span structures:

Clear-span structures provide clear space beneath the fabric, free of poles and other supporting elements. Clear span tents are more permanent than tents and less permanent than air or tensile structures. Clear spans can accommodate doors, flooring, insulation, electricity and HVAC easier than tents. PVC coated polyester is the most widely used fabric for clear span structures.

Tension structures:

In tension structures, metal pylons, tensioning cables, wooden or metal frameworks are used to support the fabric. A relatively minimal support system, which must be rigid, is required for these structures because the fabric carries most of the load.

Air Structures:

Air pressure inside the envelope provides tensioning and maintains required configuration and stability. The main components of an air supported system are the envelope (fabric), inflation system (fans), anchorage system (cables and foundation) and doors and access equipment. PVC coated polyester is the most widely used fabric. There are approximately 150 big structures in the world which were built within the last twenty years including Silver Dome in Detroit (where Teflon coated glass fabric was used).

Geotextiles:

An important branch of civil engineering dealing with the behavior and usage of soils is known as geo-technology and the textiles used in this area are known as Geo-textiles. Geotextiles are a member of a larger family called geosynthetics. Geotextiles are the largest group of geosynthetics in terms of volume. They are used in geotechnical engineering, heavy construction, building and pavement construction, hydrogeology and environmental engineering. Geotextiles are traditional textile products such as woven and nonwoven fabrics.

Awnings and Canopies:

Awnings are widely used in commercial and residential buildings for decoration, protection or visibility. Canopies, patio covers and porch awnings are the leading products in awning business. Fabric awnings and canopies are the most common types of shading structures. The main difference between an "awning" and a "canopy" is that a canopy requires support in addition to the anchoring that attaches it to a building. A fabric canopy is defined by BOCA as "an architectural projection that provides weather protection, identify and/or decoration and is ground supported by the building to which the canopy is attached."

Textiles as Roofing Materials:

Single-ply and multi-ply materials are used in the roofing market to protect buildings. In traditional built-up roofing (BUR), alternating plies of felts, fabrics or mats are assembled in place and bonded together with layers of bituminous products such as asphalt or coal tar.

Storage Vessels:

Flexible coated fabrics are used in collapsible storage containers. The major requirements for such storage systems are high tear and tensile strength with minimal weight. Examples of these types of structures include liners for transport containers and reservoirs, gas holders, marine dracones, and portable liquid (fuel, water) containment systems.

Interior Textiles:

Interior textiles include carpets, bedding products, toweling products, table linen, curtains and upholstery fabrics and as the number of houses increases, so does the potential market for these products. Other products include carpets(woven, tufted and needle felt); Bedding products (sheets, blankets, pillow cases and duvet covers); toweling products (including towels of every type, kitchen towels and flannels); Table linen, net curtains, solid drapes and upholstery fabrics, cushion covers, made-ups and bed linen, carpets and floor coverings, wall coverings(noise abatement panels and decorative panels). World markets for Interior Textiles to 2012 is a major new market reports assembled by the internationally renowned organization Comite international de la Rayonne et des Fibres Synthetiques (CIRFS).

The potential for Home Textiles is enormous but the business of manufacturing furnishing fabric for interiors is still at a nascent stage in the vastness of one of India's major economic activities: the textile industry. The textile industry is still largely focused on the apparel segment. Some manufacturers saw the growth potential in dressing Indian interiors and took an early lead in the game. Reliance for one, anticipated the possibilities for home furnishings in India, and launched Harmony, its home textiles brand way back in 1988. For fabric manufactuer's looking at home textiles, the domestic market is reportedly growing at a healthy annual rate of 10-12 per cent.

Traditionally, manufacturers of Home Textiles in India have preferred cotton fibre to synthetics. Viscose dyed yarn had a fair share in this segment. Slowly the use of polyester is increasing.

Summary:

The potential uses for textiles in architecture and construction are almost limitless. The difficulties for textile manufacturers operating in this market include the strongly cyclical nature of the construction industry and the unevenness of major projects, the long testing and acceptance procedures and, perhaps above all, the task of communicating these developments to a diverse and highly fragmented group of key specifiers, including architects, construction engineers and regulatory bodies. The construction requirements, practices and standards of just about every country and region are different and it has, so far, proved very difficult for any acknowledged global leaders to emerge in this market.

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References:

A.R.Harrocks and S.C.Anand, Handbook of Technical textiles, The Textile Institute, Woodhead Publishing Ltd., 2000, p 34.
Sabit Adanur, Wellington Sears Handbook of Industrial Textiles, Technomic Publishing Co. Inc., 1995, p 201.
M.L.Gulrajani, Manmade Textiles in Developing Countries, The Textile Association, India, 1985, p 178.
Interior Textiles Scope, The Indian Textile Journal, p 16.
Roshan L.Shishoo, Technical textiles Technological and market developments and trends, Indian Journal of Fibre & Textile Research, Vol 22, Dec 1997, p 213.
Recron Perfection, A Reliance publication, April-June 2002, p 5.
Carpet, Flooring Demand continues to rise, IFJ, Feb 2003, p 30.