TENSILE STRUCTURE

RIDDHI PATELMARGESH PATEL TWINKLE ROJIWADIAHARSHIL NAIR

DefinitionTension roofs or canopies are those in which every part of the structure is loaded only in tension ,with no requirement to resist compression or bending forces

Types of structure with significant tension membersLinear structure1. Draped cables2. Suspension bridge3. Cable trusses4. Straight tensioned cables

Three-dimensional structures

1. Bicycle wheel (can be used as a roof in a horizontal orientation)2. 3D cable trusses3. Tensigrity structures

Surface-stressed structures1. Prestressed membranes2. Pneumatically stressed membranes3. Gridshell4. Fabric structure 

Tensile Structure Materials Structural Fabric

Structural fabric is the material that defines lightweight tensile structures.

Requirements

As a primary structural element, it must have the strength to span between supporting elements, carry snow and wind loads, and be safe to walk on. As enclosure element, it needs to be airtight, waterproof, fire resistant and durable. As daily use element, it requires to transmit daylight, reflect heat, control sound, and be easy to keep clean.

Fabric Membranes

PTFE Fiberglass PTFE, or polytetrafluoroethylene, is a Teflon®-coated woven fiberglass membrane that is extremely durable and weather resistant. PTFE fiberglass membranes can be installed in climates ranging from the frigid arctic to the scorching desert heat with a project life in some cases exceeding 30 years. ETFE Film ETFE (Ethylene Tetrafluoroethylene) can be applied in multiple ways such as single, double, or triple layered applications. The material is durable, highly transparent and very lightweight in comparison to glass structures.

PVC PVC, or polyvinyl chloride, is available as a woven or non-woven material. PVC membrane is a cost-effective alternative to traditional roofing systems and can be produced in a multitude of colors to coordinate with individual building project needs.

Insulated Tensioned Membrane Tensotherm™ is a composite system comprised of a PTFE fiberglass membrane exterior skin, a thin translucent insulation blanket embedded with aerogel, and a thinner and lighter acoustic or vapor barrier interior liner.

 ePTFE PTFE-coated high translucency (ePTFE) fabric membrane is a dynamic tensile material unmatched for its aesthetics and durability, which is a woven, non-flammable material uses 100 percent fluoropolymer coating and can offer up to 40 percent light transmission (versus just 13 percent with PVC), eliminating glare to allow broad illumination throughout a given interior space.  

Rigid Structural Elements Rigid structural elements, such as masts, struts and arches, are to support the flexible fabric and cable membrane, generate its peaks, form its edges, and create the anchors that hold it down.

Requirements

The rigid elements in tensile structures must be strong, light, reliable, readily available, easy to fabricate, transport and erect.

Sample Materials

Steel, Reinforced Concrete, Pre-stress Concrete, Laminated Wood, Aluminum, Composite Synthetic Materials.

   Steel Frame

Laminated wood arches

Cables Cables serve a number of functions in tensile structure applications: reinforcement of the fabric where the spans and stresses get too large; linear tension support elements along ridges, valleys and edges; tie-backs and stays to stabilize rigid support element. Requirements The cables need to be light, high-strength and flexible to some extent.

Sample Materials High Strength Bridge Strand, Steel, Kavlar Fiber, Glass Fiber.

  

High-strength Steel Cable 

    Main Stay Cable End Fittings 

              

examples of tensile structureFrom nature

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