Tensile structures provide large column-free interior spaces through the use of tensioned fabric membranes maintained under tension by cable or truss networks. They offer several advantages over conventional structures like flexibility in design, natural daylighting, low costs, and minimal maintenance. However, the lightweight nature of fabric requires careful consideration of structural form finding, static and dynamic load analysis, and material patterning during the design process to develop stable, efficient tensile structures.

1. Tensile structure Deepak Kumar, MSA

2. “I am concerned with the way in which
the language of engineering can be
turned into the language of the
body,” Anish Kapoor
PVC TENSILE STRUCTURE COMPLETED IN 2009
LOCATION Gibbs Farm, Kaipara Harbour, New Zealand
FABRIC AREA 4,300M2 / 46,284FT2
FABRIC TYPE PVC - FERRARI 1202T2 RED
ARCHITECT Structure Design
World famous sculptor selects Structurflex

3. http://www.structurflex.com/projects/

4. Bedouin (a nomadic Arab) Tents
History

5. Kazakh Mongolian(nomad) yurt

6. •And there’s evidence that
the Romans even covered
the Colosseum with
massive canopies, hoisted
by an intricate system of
pulleys, to protect the
audience from the
elements.
•But they really came into
their own in the last half of
the 20th century, when
designs like this by
Germany’s Frei Otto.

7. •Large flat pieces of fabric are
very poor at resisting loads.
•Imagine four of you each pulling
on the strings laced through a
tennis ball. Fig 1. A fifth person
pushing down on the ball can
deflect it easily.
•Fig 2. The ball is now locked in
space. Apply this principle to
fabric and you have created
‘anticlastic’ double curvature.
Sounds grand but actually is
simply derived from one of three
fabric shapes; the hypar, the cone
and the barrel.
Why tensiles are the
shape they are?

8. The world's first tensile
steel Shell by Vladimir Shukhov (during
construction), Nizhny Novgorod, 1895

9. Tensioned Fabric Structure: A structure where the exterior shell is a fabric material spread over a
framework. The fabric is maintained in tension in all directions to provide stability.
or
Tensile Structures
Tension 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.
DENVER INTERNATIONAL AIRPORT

10. PIER SIX PAVILION
Baltimore, Maryland
OPEN STRUCTURE

11. CHICAGO’S NAVY PIER

12. • Unique designs
• Lightweight and flexible
• Environmentally sensitive
• High strength weight ratio
• Little to no rigidity
• Loss of tension is dangerous for stability
• Thermal values limit use
DISADVANTAGESADVANTAGES
• FABRIC STRUCTURES CANNOT TAKE HEAVY WEATHER CONDITIONS FALSE
• FABRIC IS ELASTIC AND STRETCHES Fabric has a strong tensile strength and
will creep (stretch very slightly) only a few percent over 20 years of use.
COMMON MISCONCEPTIONS

13. Types of structures:
•Stayed
•Suspended
• Anticlastic
• Pneumatic
•Trussed
Types of structure with
significant tension members

14. STAYED:
To span railroad trucks
underneath, the truss roof is
suspended by stay cables.
McCormick exhibit hall Chicago
Architect/Engineer: SOM

15. Renault Center Swindon, UK
Architect: Norman Foster

16. SUSPENDED STRUCTURES:
GOLDEN GATE Bridge,sanfrancisco, USA

17. Oakland Coliseum (1967)
Architect: SOM
Engineer: Ammann and Whitney
• Diameter 400 ft
• Outer concrete compression ring
• Inner steel tension ring
• Steel strands for main support
• Concrete ribs resist unbalanced load
• X-columns resist lateral seismic load

18. here is the sequence of force
transmission for the cable-stayed
bridge:
1. to the deck;
2. to the stay cable;
3. to the bridge tower;
4. and also is the last, to the
foundation.
if one car pass on the bridge,
here is the sequence of force
transmission for the
suspension bridge:
1. to the deck;
2. to the suspender;
3. to the main cable;
4. to the bridge tower;
5. and also is the last, to the
foundation.

19. ANTICLASTIC STRUCTURES
1 Opposing strings
stabilize a point in space
2 Several opposing strings
stabilize several points
3 Anticlastic curvature
stabilizes a membrane

20. TYPES OF FABRIC STRUCTURES
• Saddle roof
• Mast supported
• Arch supported
• Point supported
• Combinations

21. SADDLE ROOF
• Four or more point system when the fabric
is stretched between a set of alternating
high and low points

22. MAST SUPPORTED
• Tent - like structures containing one or more
peaks supported by poles (masts) or a
compression ring that connects the fabric to
the central support.

23. ARCH SUPPORTED
• Curved compression members are used as the
main supporting elements and cross arches
are used for lateral stability.

24. COMBINATIONS
• Combination of several support types.

25. INCLUDE CURVATURE , SADDLE SHAPES
IT INCLUDES:
ARCH SHAPE
WAVE SHAPE
POINT SHAPE
ARCH SHAPE
WAVE SHAPE
POINT SHAPE
SADDLE SHAPE

26. Swiss Expo 64 Lausanne
Architect: Saugey / Schierle
Engineer: Froadvaux et Weber
• 26 restaurants featured regional cuisines
• Symbolized sailing and mountain peaks
Saddle

27. Skating rink Munich
Architect: Ackermann
Engineer: Schlaich / Bergermann
• Prismatic steel truss arch, 100
m span
• Anticlastic cable nets
• Wood slats
• Translucent fabric
Arch

28. Point Shapes
1 Mast punctures fabric
2 Radial cables
3 Ring with radial cables
4 Loop cable
5 Dish top
6 Eye cable
7 Twin mast rows
8 Three mast rows
9 Suspension cables
10 Supporting cables

29. German Pavilion, Montreal Expo 1967
Architect: Rolf Gutbrot / Frei Otto
Engineer: Fritz Leonhard

30. Retractable umbrellas Medina
Architect: Bodo Rush

31. PENUMATIC STRUCTURES
AIR INFLATED STRUCTURES
Silverdome
Pontiac,
STADIUM

32. TRUSSED STRUCTURES:
Stadium roof Oldenburg, Germany
Engineer: Schlaich Bergermann
Cable truss & anticlastic membrane panels

33. MATERIAL FOR TENSILE MEMBRANE:
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.
Sample Materials
Fiberglass, Polyester Cloth, PVC, Teflon.

34. • PVC
• Less expensive
• 15 to 20 year life span
• Easy to erect
• SILICON GLASS
• Higher tensile strength
• Brittle, subject to damage from flexing
• 30+ year life span
• TEFLON GLASS
• Similar to silicon glass, less brittle.
TYPES OF FABRIC MEMBRANES

35. MEMBRANE
Forms the enclosure of the structure. Connections can be glued
or heat welded.

36. • Connection to concrete foundation pillar
• MAST SUPPORTED
BASE PLATE

37. Rigid Structural Elements
Steel Frame Rigid structural elements, such as arches, are to support the flexible
fabric and cable membrane, generate its peaks, form its edges.
Requirements
The rigid elements in tensile structures must be strong, light, reliable,
readily available, easy to fabricate, transport .
Sample Materials
Steel, Reinforced Concrete,Laminated Wood, Aluminum.
STEEL ROOF
LAMINATED WOOD ARCHES

38. BALE RING / MEMBRANE PLATE
• Provide a link between the membrane and structural elements..
– Bale rings are used at the top of conical shapes.
– Membrane plates accept centenary cables and pin connection
hardware.

39. SPECIALIZED HARDWARE
Tensioner
Extruded section with
membrane plate and
centenary cables
Tripod head with
centenary cables
Centenary cables at
a side connection

40. CABLE CLAMPS

41. WATER DRAINAGE VIA MEMBRANE PLATES
OPEN STRUCTURE

42. 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 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,
Glass Fiber.

43. High-strength Steel CablE
GRID SHOWS
THE BASE OF
CABLE IN
STRUCTURES

44. ADVANTAGES FABRIC TENSILE STRUCTURE
One of the main advantages of fabric structure is that you can install it rapidly and easily.
Tension fabric buildings provide abundant daytime lighting that is bright and natural,
the interior of a fabric structure is an inviting environment that people, plants and animals
thrive in.
Fabric buildings are Acoustics exceptional; no sounds of pelting rain.
Fabric buildings have Low cost per square foot, Initial investment is low.
Fabric buildings are self cleaning; never needs painting; dust, dirt, pollutants wash off with
Water no rotting parts to replace.
Fabric structures are durable, corrosion resistance. salt, fertilizer and other corrosive materials
have virtually no effect on polyethylene fabric.
Flexibility, when a large clearspan building with tall overhead clearances is needed,
a fabric structure is an economical solution.

45. SOLAR BEHAVIOR

46. ENVIRONMENTAL IMPACT
• Longer life cycles of materials.
• Materials can be re-used in form.
• Most materials are completely recyclable.
• Less impact on site.
• Less construction debris after demolition.

47. There are many great advantages and functional benefits of tensile membrane
structures and here are few reasons why:
Flexible Design Aesthetics - Tensile membrane structures provide virtually
unlimited designs of distinctive elegant forms that can be realized because of the
unique flexible characteristics of membrane resulting in an iconic and unique
structure or feature for any building owner, city or even region.
Outstanding Translucency – In daylight, fabric membrane translucency offers soft
diffused naturally lit spaces reducing the interior lighting costs while at night,
artificial lighting creates an ambient exterior luminescence.
Excellent Durability – With several different membranes in the market place such
as PTFE fiberglass, ETFE film, PVC, and ePTFE, the durability and longevity of
tensile membrane structures have been proven.
ADVANTAGES

48. Lightweight Nature - The lightweight nature of membrane is a cost effective
solution that requires less structural steel to support the roof compared to
conventional building materials, enabling long spans of column-free space.
Low Maintenance – Tensile membrane systems are somewhat unique in that they
require minimal maintenance when compared to an equivalent-sized conventional
building.
Cost Benefits – Most tensile membrane structures have high sun reflectivity and
low absorption of sunlight, thus resulting in less energy used within a building and
ultimately reducing electrical energy costs.

49. Design process for
membrane structures:
01 . Form finding
Establish the
equilibrium where the
architectural idea and
structural idea should
converge to a point
which is both
aesthetically pleasing
and structurally
efficient.
Consider the issue
related to chosen
material so
manufacture are
involved from first day
of design.

50. 02. Static analysis:
Predicting the stress and
development which rise in the
tensioned surface due to the
presence of external load such
as snow or wind.
03. Patterning:
The three dimensional surface,
found by the means of the
form finding , is flattened
obtaining a two dimensional
cutting pattern for
manufacturing of fabric.
04. Dynamic analysis:
Evaluation of the interaction
between a fluctuating external
load and the structure.